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As filed with the Securities and Exchange Commission on October 13,November 8, 2006

Registration No. 333-136861



SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549


Amendment No. 12 to
FORM S-4
REGISTRATION STATEMENT UNDER
THE SECURITIES ACT OF 1933


ALDABRA ACQUISITION CORPORATION
(Exact name of registrant as specified in its charter)

Delaware
(State or other jurisdiction of
incorporation or organization)
 6770
(Primary Standard Industrial
Classification Code Number)
 20-1918691
(I.R.S. Employer
Identification Number)

c/o Terrapin Partners LLC
540 Madison Avenue, 17th Floor
New York, New York 10022
(212) 332-3555710-4100

(Address, including zip code, and telephone number, including area code, of registrant's principal executive offices)


Nathan D. Leight, Chairman of the Board
Aldabra Acquisition Corporation
c/o Terrapin Partners LLC
540 Madison Avenue, 17th Floor
New York, New York 10022
(212) 332-3555710-4100
(Name, address, including zip code and telephone number, including area code, of agent for service)

GREAT LAKES DREDGE & DOCK HOLDINGS CORP.
(Exact name of registrant as specified in its charter)

Delaware
(State or other jurisdiction of
incorporation or organization)
 1600
(Primary Standard Industrial
Classification Code Number)
 20-5336063
(I.R.S. Employer
Identification Number)

c/o Terrapin Partners LLC
540 Madison Avenue, 17th Floor
New York, New York 10022
(212) 332-3555710-4100

 

Nathan D. Leight, Chairman of the Board
Aldabra Acquisition Corporation
c/o Terrapin Partners LLC
540 Madison Avenue, 17th Floor
New York, New York 10022
(212) 332-3555710-4100
(Address, including zip code, and telephone number, including area code, of registrant's principal executive offices) (Name, address, including zip code, and telephone number, including area code, of agent for service)



Copies to:
Jack I. Kantrowitz
Sidley Austin LLP
787 Seventh Avenue
New York, NY 10019
(212) 839-5300
 Carol Anne Huff
Kirkland & Ellis LLP
200 E. Randolph Drive
Chicago, IL 60601
(312) 861-2000

Approximate date of commencement of proposed sale to the public: As soon as practicable after this Registration Statement becomes effective.


        If the securities being registered on this Form are being offered in connection with the formation of a holding company and there is compliance with General Instruction G, check the following box:    o

        If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering:    o

        If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering:    o


        The registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until this Registration Statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.




The information in this proxy statement/prospectus is not complete and may be changed. Aldabra Acquisition Corporation and Great Lakes Dredge & Dock Holdings Corp. may not distribute and issue the shares of common stock being registered pursuant to this registration statement until the registration statement filed with the Securities and Exchange Commission is declared effective. This proxy statement/prospectus is not an offer to sell these securities and Aldabra Acquisition Corporation and Great Lakes Dredge & Dock Holdings Corp. are not soliciting an offer to buy these securities in any jurisdiction where such offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED OCTOBER 13,NOVEMBER 8, 2006

GRAPHICGRAPHIC


ALDABRA ACQUISITION CORPORATION
c/o TERRAPIN PARTNERS LLC
540 MADISON AVENUE, 17TH FLOOR
NEW YORK, NY 10022

[    •    ], 2006

        Dear Aldabra Stockholder:

        You are cordially invited to attend a special meeting of the stockholders of Aldabra Acquisition Corporation ("Aldabra"), relating to the proposed merger of GLDD Acquisitions Corp. ("Great Lakes"), the parent company of Great Lakes Dredge & Dock Corporation, with and into Aldabra Merger Sub, L.L.C., a wholly-owned subsidiary of Aldabra ("Merger Sub"), to be held at [10:10:00 a.m.], Eastern Standard time, on [INSERT DATE],December 14, 2006, at Sidley Austin LLP,AustinLLP, 787 Seventh Avenue, New York, NY 10019.

        At the special meeting, you will be asked to consider and vote upon the following proposals:

1.
to adopt the Agreement and Plan of Merger, dated as of June 20, 2006, by and among Great Lakes, Aldabra, Merger Sub, and certain of their respective stockholders as representatives of the parties to the merger agreement (the "merger agreement"), and to approve the transactions contemplated by the merger agreement, including the merger of Great Lakes with and into Merger Sub (the "Great Lakes merger");

2.
to amend and restate Aldabra's certificate of incorporation to increase the number of authorized shares of common stock of Aldabra, par value $0.0001 per share, to a number sufficient to satisfy Aldabra's obligations under the merger agreement with respect to the issuance of Aldabra common stock, but in no event to exceed an additional 40,000,000 shares;

3.
to elect eight members of the Board of Directors of Aldabra from the completion of the Great Lakes merger until their successors are duly elected and qualified;

4.
to adopt the Agreement and Plan of Merger, dated as of August 21, 2006, by and among Aldabra, Great Lakes Dredge & Dock Holdings Corp. ("Great Lakes Holdings") and GLH Merger Sub, L.L.C. (the "holding company merger agreement"), and to approve the transactions contemplated thereby, including the merger of Aldabra with and into GLH Merger Sub, L.L.C. (the "holding company merger"). The holding company merger will occur not more than one business day following the Great Lakes merger and is being effected for the purpose of adopting new transfer restrictions to regulate the ownership of Great Lakes Holdings common stock by persons that are not citizens of the United States for purposes of maritime law; and

5.
to consider and act upon any other matters that may properly be brought before the special meeting or at any adjournments or postponements thereof.

        The adoption of any of these proposals is conditioned upon the adoption of all of the other proposals.

        All shares of Great Lakes capital stock issued and outstanding immediately prior to the effective time of the Great Lakes merger (other than shares held in the treasury of Great Lakes, shares owned by Aldabra or by any wholly-owned subsidiary of Great Lakes or by dissenting stockholders who perfect



their appraisal rights) shall be cancelled and exchanged for the merger consideration. Such merger consideration will consist of a base consideration of $160,000,000 in shares of Aldabra common stock (but will not in any event be less than 27,273,000 shares) and an incremental consideration (positive or negative, not to exceed 7,500,000 shares) based on the amounts, as of the end of the day before the closing, by which (i) Great Lakes' net indebtedness is greater or less than $250,000,000, (ii) Great



Lakes' net working capital is greater or less than $47,097,000, and (iii) Aldabra's net working capital is less than $50,000,000. The exchange ratio will be based on the average closing price of Aldabra common stock for the ten trading days ending three trading days prior to the consummation of the Great Lakes merger. The exact number of shares to be delivered in the Great Lakes merger is not determinable at this time, since the exchange ratio used to calculate the number of shares of Aldabra common stock to be delivered is not yet known and since the number of shares of Aldabra common stock that will be issued will vary based on working capital and indebtedness adjustments, but in no event will the aggregate number of shares of Aldabra common stock issuable to Great Lakes stockholders exceed 40,000,000 shares. Only by way of example, if the closing of the Great Lakes merger had occurred on August 31, 2006, the average trading price would have been $5.36 per share, and based on Great Lakes' net indebtedness and working capital and Aldabra's working capital, in each case as of August 31, 2006, the merger consideration would have been 29,570,968 shares of Aldabra common stock.

        Each holder of shares of preferred stock of Great Lakes outstanding immediately prior to the effective time of the Great Lakes merger will be entitled to receive, from the merger consideration, a number of shares of Aldabra common stock which, when multiplied by the ten days average trading price of Aldabra common stock ending three trading days prior to the consummation of the Great Lakes merger, equals the sum of the liquidation value of such shares plus the aggregate accumulated dividends and all other accrued but unpaid dividends on such shares. Each holder of shares of common stock of Great Lakes outstanding immediately prior to the effective time of the Great Lakes merger will be entitled to receive a pro rata share of the remaining merger consideration.

        FollowingThrough the mergers, Great Lakes Holdings intends to merge eachmerger, Aldabra will acquire Great Lakes, the parent company of GLH Merger Sub, L.L.C., Aldabra Merger Sub, L.L.C. and Great Lakes Dredge & Dock Corporation intoCorporation. Then, pursuant to the holding company merger, Aldabra will merge with a subsidiary of Great Lakes Holdings and, to change the nameafter a series of parent-subsidiary mergers, Great Lakes Holdings towill be the sole surviving company and will be renamed Great Lakes Dredge & Dock Corporation.

        The affirmative vote of holders of a majority of the shares issued in Aldabra's initial public offering (the "IPO Shares") voting in person or by proxy at the special meeting, and the affirmative vote of holders of a majority of the outstanding shares on the record date (including the holders of shares issued prior to Aldabra's IPO who have agreed to vote all their shares in accordance with the majority of the votes cast by holders of IPO Shares), are required to approve the merger agreement and the transactions contemplated thereby. The affirmative vote of holders of a majority of the outstanding shares of Aldabra common stock outstanding on the record date is required to approve the amendment proposal. The affirmative vote of holders of a majority of the outstanding shares of Aldabra common stock outstanding on the record date is required to approve the holding company merger proposal. The eight directors to be elected at the special meeting will be elected by a plurality of the votes cast by the stockholders present in person or by proxy and entitled to vote.

        Each Aldabra stockholder that holds IPO Shares has the right to vote against the Great Lakes merger proposal and at the same time demand that Aldabra convert such stockholder's shares into an amount of cash equal to the pro rata portion of the trust account in which a substantial portion of the net proceeds of Aldabra's initial public offering, plus interest thereon, are deposited. These shares will be converted into cash only if the merger is completed. However, if the holders of 20% or more of the IPO Shares vote against the merger proposal and demand conversion of their shares into a pro rata portion of the trust account, Aldabra will not consummate the merger. If this were to occur, the Board of Directors of Aldabra will meet to decide to call a meeting of Aldabra's stockholders and to recommend Aldabra's dissolution and liquidation, which will require the filing of appropriate documentation with the SEC. Once this documentation is final, an Aldabra stockholders' meeting would be held to decide to dissolve and liquidate Aldabra. The funds in the trust account would be



distributed to the stockholders of Aldabra only after that vote to dissolve and liquidate, which would probably be a considerable time after the negative vote on this transaction.



        Assuming an exchange ratio of $[a trading price as of a date not more than five business days prior to mailing]$5.70 per share, immediately after completion of the merger Aldabra stockholders will own approximately [    ]%28.5% of the combined company's issued and outstanding common stock and approximately [    ]%19.4% of the combined company's fully diluted common stock. If holders of less than 20% of the IPO Shares vote against the merger and demand at or prior to the special meeting that Aldabra convert their shares into a pro rata portion of the trust account, then Aldabra stockholders will own a lesser percentage of the combined company's issued and outstanding shares of common stock after completion of the merger and a lesser percentage of the combined company's fully diluted common stock. These percentages do not take into account the working capital and assumed indebtedness adjustments to be made in connection with the Great Lakes merger.

        Aldabra shares of common stock, warrants and units are quoted on the Over-the-Counter Bulletin Board under the symbols ALBA.OB, ALBAW.OB and ALBAU.OB, respectively. On August 17,November 2, 2006, the closing sale price of Aldabra common stock, warrants and units was $5.35, $0.40$5.70, $0.83 and $6.13,$7.32, respectively. Great Lakes capital stock is not listed or quoted on any national securities exchange, The Nasdaq Stock Market, or the Over-the-Counter Bulletin Board. However, Great Lakes has an aggregate principal amount of $175,000,000 of publicly tradable bonds.

        SEE "RISK FACTORS" BEGINNING ON PAGE 2628 OF THE ACCOMPANYING PROXY STATEMENT/PROSPECTUS FOR A DISCUSSION OF CERTAIN FACTORS THAT SHOULD BE CONSIDERED IN EVALUATING THE PROPOSALS DESCRIBED HEREIN AND THE SECURITIES OFFERED HEREBY.

        AFTER CAREFUL CONSIDERATION OF THE TERMS AND CONDITIONS OF THE GREAT LAKES MERGER PROPOSAL, THE AMENDMENT PROPOSAL, THE HOLDING COMPANY MERGER PROPOSAL AND THE ELECTION OF DIRECTOR NOMINEES, THE BOARD OF DIRECTORS OF ALDABRA BELIEVES THAT THE GREAT LAKES MERGER PROPOSAL, THE AMENDMENT PROPOSAL, THE HOLDING COMPANY MERGER PROPOSAL AND THE ELECTION OF DIRECTOR NOMINEES, ARE FAIR TO, AND IN THE BEST INTERESTS OF, ALDABRA AND ITS STOCKHOLDERS. THE BOARD OF DIRECTORS HAS UNANIMOUSLY APPROVED THE GREAT LAKES MERGER PROPOSAL, THE AMENDMENT PROPOSAL AND THE HOLDING COMPANY MERGER PROPOSAL AND UNANIMOUSLY RECOMMENDS THAT YOU VOTE FOR THE ADOPTION OF THE MERGER AGREEMENT AND THE TRANSACTIONS CONTEMPLATED THEREBY AND FOR EACH OF THE OTHER PROPOSALS LISTED ABOVE.

        The accompanying proxy statement/prospectus provides detailed information concerning the Great Lakes merger proposal, the amendment proposal, the holding company merger proposal, the election of directors nominees, and certain additional information, including, without limitation, the information set forth under the heading "Risk Factors," all of which you are urged to read carefully. It is important that your Aldabra common stock be represented at the special meeting, regardless of the number of shares you hold. Therefore, please sign, date and return your proxy card as soon as possible, whether or not you plan to attend the special meeting. This will not prevent you from voting your shares in person if you subsequently choose to attend the special meeting.

 Sincerely,

 


Nathan D. Leight
Chairman of the Board

        Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of the transactions described in this proxy statement/prospectus or the offer of the shares of common stock described in this proxy statement/prospectus to be issued in connection with



the mergers or determined whether this proxy statement/prospectus is truthful or complete. Any representation to the contrary is a criminal offense.



        This proxy statement/prospectus is dated [    •    ],November 10, 2006 and is first being mailed to Aldabra stockholders on or about [    •    ],November 10, 2006.

        In connection with this offering, no person is authorized to give any information or to make any representations not contained in this proxy statement/prospectus. If information is given or representations are made, you may not rely on that information or those representations as having been authorized by Aldabra. This proxy statement/prospectus is neither an offer to sell nor a solicitation of an offer to buy securities where an offer or solicitation would be unlawful. You may not assume from delivery of this proxy statement/prospectus, or from a sale made under this proxy statement/prospectus, that Aldabra's affairs are unchanged since the date of this proxy statement/prospectus or that the information contained in this proxy statement/prospectus is correct as of any time after the date of this proxy statement/prospectus.

        This proxy statement/prospectus incorporates important business and financial information about Aldabra that is not included in or delivered with the document. This information is available without charge to stockholders upon written or oral request. The request should be sent to:

Nathan D. Leight
Aldabra Acquisition Corporation
c/o Terrapin Partners LLC
540 Madison Avenue, 17th Floor
New York, NY 10022

        To obtain timely delivery of requested materials, stockholders must request the information no later than five days before the date they submit their proxies or attend the special meeting. The latest date to request the information to be received timely is December 8, 2006.



NOTICE OF MEETING


ALDABRA ACQUISITION CORPORATION
c/o Terrapin Partners LLC
540 Madison Avenue, 17th Floor
New York, New York 10022


NOTICE OF SPECIAL MEETING OF STOCKHOLDERS
TO BE HELD ON ,DECEMBER 14, 2006


        You are cordially invited to attend the special meeting of the stockholders of Aldabra Acquisition Corporation ("Aldabra"), relating to the proposed merger of GLDD Acquisitions Corp. ("Great Lakes"), the parent company of Great Lakes Dredge & Dock Corporation, with and into Aldabra Merger Sub, L.L.C., a wholly-owned subsidiary of Aldabra ("Merger Sub"), to be held on [INSERT DATE],December 14, 2006, at [10:10:00 a.m.], Eastern Standard time at Sidley Austin LLP,AustinLLP, 787 Seventh Avenue, New York, NY 10019 for the following purposes:

        The adoption of any of these proposals is conditioned upon the adoption of all of the other proposals.

        FollowingThrough the mergers, Great Lakes Holdings intends to merge eachmerger, Aldabra will acquire Great Lakes, the parent company of GLH Merger Sub, L.L.C., Aldabra Merger Sub, L.L.C. and Great Lakes Dredge & Dock Corporation intoCorporation. Then, pursuant to the holding company merger, Aldabra will merge with a subsidiary of Great Lakes Holdings and, to change the nameafter a series of parent-subsidiary mergers, Great Lakes Holdings towill be the sole surviving company and will be renamed Great Lakes Dredge & Dock Corporation.



        The Board of Directors of Aldabra fixed the close of business on [INSERT RECORD DATE]November 10, 2006 (the "Record Date"), as the date for which Aldabra stockholders are entitled to receive notice of, and to vote at, the special meeting. Only the holders of record of Aldabra common stock on the Record Date



are entitled to have their votes counted at the special meeting and any adjournments or postponements of it.

        On the Record Date, there were 11,200,000 outstanding shares of Aldabra common stock, of which 9,200,000 were issued to the public in its initial public offering and 2,000,000 were issued to its initial stockholders prior to its IPO, each of which is entitled to one vote per share at the special meeting. The holders of the shares issued prior to Aldabra's IPO, which are referred to as the "Private Shares," are held by its directors, each of whom has agreed to vote all of his shares with respect to the merger proposal in accordance with the majority of the votes cast by the holders of the shares issued in the IPO, which we refer to as the "IPO Shares." If holders of a majority of the IPO Shares voting in person or by proxy at the special meeting vote against, or abstain with respect to, the Great Lakes merger proposal, such proposal will not be approved. Record holders of Aldabra warrants do not have voting rights.

        Your vote is important. Please sign, date and return your proxy card as soon as possible to make sure that your shares are represented at the special meeting. If you are a stockholder of record of Aldabra common stock, you may also cast your vote in person at the special meeting. If your shares are held in an account at a brokerage firm or bank, you must instruct your broker or bank on how to vote your shares. If you do not vote or do not instruct your broker or bank how to vote, it will have the same effect as voting against each of the proposals listed above.

        Any proxy may be revoked at any time prior to its exercise by delivery of a later dated proxy, using the toll free telephone number or by voting in person at the special meeting. By authorizing your proxy promptly, you can help us avoid the expense of further proxy solicitations.

        After careful consideration of the terms and conditions of the Great Lakes merger proposal, the amendment proposal, the holding company merger proposal and the election of the director nominees, the Board of Directors of Aldabra believes that the Great Lakes merger proposal, the amendment proposal, the holding company merger proposal and the election of the director nominees are fair to, and in the best interests of, Aldabra and its stockholders. The Board of Directors of Aldabra has unanimously approved the Great Lakes merger proposal, the amendment proposal and the holding company merger and unanimously recommends that you vote FOR the adoption of the merger agreement and the transactions contemplated thereby and for each of the other proposals listed above.

        Your attention is directed to the proxy statement/prospectus accompanying this notice (including the exhibits thereto) for a more complete statement regarding the matters proposed to be acted on at the special meeting. We encourage you to read this proxy statement/prospectus carefully. If you have any questions or need assistance voting your shares, please call our proxy solicitor, MacKenzie Partners, Inc. at 1-800-322-2885 or email our proxy solicitor at proxy@mackenziepartners.com.

 BY ORDER OF THE BOARD OF DIRECTORS

 


Jason G. Weiss
Chief Executive Officer and Secretary

[    •    ], 2006


GRAPHICGRAPHIC

PROXY STATEMENT FOR SPECIAL MEETING OF STOCKHOLDERS OF
ALDABRA ACQUISITION CORPORATION
TO BE HELD ON [    •    ],DECEMBER 14, 2006



PROSPECTUS FOR UP TO
40,000,000 SHARES OF COMMON STOCK OF
ALDABRA ACQUISITION CORPORATION



PROSPECTUS FOR UP TO
51,200,000 SHARES OF COMMON STOCK OF
GREAT LAKES DREDGE & DOCK HOLDINGS CORP.
AND 18,400,000 SHARES OF COMMON STOCK OF
GREAT LAKES DREDGE & DOCK HOLDINGS CORP.
ISSUABLE UPON EXERCISE OF THE WARRANTS



        A special meeting of stockholders of Aldabra Acquisition Corporation ("Aldabra") will be held at [10:10:00 a.m.,] Eastern Standard time, on [    •    ],December 14, 2006, at the offices of Sidley Austin LLP,AustinLLP, 787 Seventh Avenue, New York, NY 10019. At this important meeting, Aldabra stockholders will be asked to consider and vote upon the proposals described in the Notice of Meeting and on page [40]47 of this proxy statement/prospectus:prospectus.

        The merger consideration, which is the number of shares of Aldabra common stock to be issued to the stockholders of GLDD Acquisitions Corp. ("Great Lakes") in the merger (the "Great Lakes merger") of Great Lakes, the parent company of Great Lakes Dredge & Dock Corporation, with and into Aldabra Merger Sub, L.L.C. ("Merger Sub") , will consist of a base consideration of $160,000,000 in shares of Aldabra common stock (but will not in any event be less than 27,273,000 shares) and an incremental consideration (positive or negative, not to exceed 7,500,000 shares) based on the amounts, as of the end of the day before the closing, by which (i) Great Lakes' net indebtedness is greater or less than $250,000,000, (ii) Great Lakes' net working capital is greater or less than $47,097,000, and (iii) Aldabra's net working capital is less than $50,000,000. The exchange ratio will be based on the average closing price of Aldabra common stock for the ten trading days ending three trading days prior to the consummation of the Great Lakes merger. The exact number of shares to be delivered in the Great Lakes merger is not determinable at this time, since the exchange ratio used to calculate the number of shares of Aldabra common stock to be delivered is not yet known and since the number of shares of Aldabra common stock that will be issued will vary based on working capital and indebtedness adjustments, but in no event will the aggregate number of shares of Aldabra common stock issuable to Great Lakes stockholders exceed 40,000,000 shares. Only by way of example, if the closing of the Great Lakes merger had occurred on August 31, 2006, the average trading price would have been $5.36 per share, and based on Great Lakes' net indebtedness and working capital and Aldabra's working capital, in each case as of August 31, 2006, the merger consideration would have been 29,570,968 shares of Aldabra common stock.

        Through the Great Lakes merger, Aldabra will acquire Great Lakes, the parent company of Great Lakes Dredge & Dock Corporation. Then, pursuant to the holding company merger, Aldabra will merge with a subsidiary of Great Lakes Holdings and, after a series of parent-subsidiary mergers, Great Lakes Holdings will be the sole surviving company and will be renamed Great Lakes Dredge & Dock Corporation.

The Aldabra units, shares of common stock and warrants are quoted on the Over-the-Counter Bulletin Board under the symbols ALBAU.OB, ALBA.OB, and ALBAW.OB, respectively. Great Lakes capital stock is not listed or quoted on any national securities exchange, The Nasdaq Stock Market, or the Over-the-Counter Bulletin Board. However, Great Lakes has an aggregate principal amount of $175,000,000 of publicly tradable bonds. Great Lakes Dredge & Dock Holdings Corp. ("Great Lakes Holdings") intends to apply to list the common stock of Great Lakes Holdings on the Nasdaq Capital Market or the Nasdaq Global Market following the merger (the "holding company merger") of Aldabra with and into GLH Merger Sub, L.L.C., a subsidiary of Great Lakes Holdings.

        This proxy statement/prospectus contains important information about the special meeting and the proposals. Please read it, including the "Risk Factors" beginning on page 26, carefully, and, if you are an Aldabra stockholder, vote your shares.

        THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED UPON THE ACCURACY OR ADEQUACY OF THIS PROXY STATEMENT/PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

        This proxy statement/prospectus is dated [    •    ],November 10, 2006 and is first being mailed to stockholders on or about that date. Subject to completion, dated October 10,November 8, 2006



TABLE OF CONTENTS

 
 Page
SUMMARY 1
QUESTIONS AND ANSWERS ABOUT THE TRANSACTIONS 1921
RISK FACTORS 2628
CAUTIONARY STATEMENT CONCERNING FORWARD-LOOKING STATEMENTS 3740
SELECTED HISTORICAL FINANCIAL INFORMATION 3841
COMPARATIVE PER SHARE INFORMATION 4245
PER SHARE MARKET PRICE INFORMATION 4346
THE SPECIAL MEETING 4447
THE MERGER 4952
THE MERGER AGREEMENT 6973
THE AMENDMENT PROPOSAL 8187
APPRAISAL RIGHTS 8288
SUMMARY OF THE HOLDING COMPANY MERGER 8591
U.S. FEDERAL INCOME TAX CONSIDERATIONS 8692
DESCRIPTION OF GREAT LAKES DREDGE & DOCK HOLDINGS CORP.'S CAPITAL STOCK AND WARRANTS 8995
COMPARISON OF STOCKHOLDERS RIGHTS 97103
INFORMATION ABOUT GLDD ACQUISITIONS CORP. 105111
INFORMATION ABOUT ALDABRA ACQUISITION CORPORATION 139147
UNAUDITED PRO FORMA CONDENSED CONSOLIDATED BALANCE SHEET AND STATEMENTS OF OPERATIONS 146154
MANAGEMENT 156164
BENEFICIAL OWNERSHIP OF COMMON STOCK OF GREAT LAKES HOLDINGS AFTER THE MERGERS 168176
SHARES ELIGIBLE FOR FUTURE SALE 171179
STOCKHOLDER PROPOSALS 172180
LEGAL MATTERS 172180
EXPERTS 172180
INDEX TO FINANCIAL STATEMENTS F-1
FINANCIAL STATEMENTS F-3
EXHIBIT A—AGREEMENT AND PLAN OF MERGER A-1
EXHIBIT B—DELAWARE APPRAISAL RIGHTS STATUTE B-1
EXHIBIT C—OPINION OF FINANCIAL ADVISOR C-1
EXHIBIT D—POST-CLOSING CERTIFICATE OF INCORPORATION AND BYLAWS OF GREAT LAKES DREDGE & DOCK HOLDINGS CORP. D-1-1
EXHIBIT E—HOLDING COMPANY MERGER AGREEMENT E-1

i



SUMMARY

        This summary highlights selected information contained elsewhere in this proxy statement/prospectus relating to the Great Lakes merger and the holding company merger and may not contain all of the information that is important to you. To understand the Great Lakes merger and the holding company merger and the related transactions fully and for a more complete description of the Great Lakes merger and other transactions contemplated by the merger agreement, you should carefully read this entire proxy statement/prospectus as well as the additional documents to which it refers, including the merger agreement attached to this proxy statement/prospectus as Exhibit A and the holding company merger agreement attached as Exhibit E. For instructions on obtaining more information, see "Who Can Answer Other Questions".

The Special Meeting

        This proxy statement/prospectus is being furnished to holders of Aldabra common stock for use at the special meeting, and at any adjournments or postponements of that meeting. At the special meeting, Aldabra stockholders will be asked to consider and vote upon proposals (1) to adopt the Agreement and Plan of Merger, dated as of June 20, 2006 (the "merger agreement"), by and among Great Lakes, Aldabra, Merger Sub, and certain of their respective stockholders as representatives of the parties to the merger agreement and to approve the transactions contemplated thereby, including the Great Lakes merger; (2) to amend and restate Aldabra's certificate of incorporation to increase the number of authorized shares of common stock of Aldabra, par value $0.0001 per share, to a number sufficient to satisfy Aldabra's obligations under the merger agreement with respect to the issuance of Aldabra common stock, but in no event to exceed an additional 40,000,000 shares; (3) to elect eight members of the board of directors of Aldabra from the completion of the Great Lakes merger until their successors are duly elected and qualified; (4) to adopt the Agreement and Plan of Merger, dated as of August 21, 2006 (the "holding company merger agreement"), by and among Aldabra, Great Lakes Holdings and GLH Merger Sub, L.L.C. and to approve the transactions contemplated thereby, including the holding company merger; and (5) to consider and act upon any other matters that may properly be brought before the special meeting or at any adjournments or postponements thereof. The special meeting will be held on [INSERT DATE],December 14, 2006, at Sidley Austin LLP, located at 787 Seventh Avenue, New York, NY 10019 at 10:00 a.m. Eastern Standard time.

Parties to the Great Lakes Merger and the Holding Company Merger

        GLDD Acquisitions Corp.    GLDD Acquisitions Corp., a Delaware corporation, is the parent company of Great Lakes Dredge & Dock Corporation, the largest provider of dredging services in the United States and the only U.S. dredging company with significant international operations. International operations averaged 16% of its revenues over the last three years. The U.S. dredging market consists of three primary types of work: capital, beach nourishment and maintenance. Over the last five fiscal years, Great Lakes has achieved a 45% average share of the U.S. dredging bid market. Great Lakes also owns an 85% interest in North American Site Developers, Inc., a large U.S. provider of commercial and industrial demolition services. Additionally, Great Lakes owns a 50% interest in a marine sand mining operation in New Jersey that supplies sand and aggregate used for road and building construction. Great Lakes has a 116-year history of never failing to complete a marine project and owns the largest and most diverse fleet in the industry, comprising over 180 specialized vessels. Great Lakes' executive offices are located at 2122 York Road, Oak Brook, Illinois 60523. Great Lakes files reports with the SEC, which are available free of charge atwww.sec.gov. GLDD Acquisitions Corp. is sometimes referred to in this proxy statement/prospectus as "Great Lakes."

        Aldabra Acquisition Corporation.    Aldabra Acquisition Corporation is a blank check company formed on November 22, 2004 to effect a merger, capital stock exchange, asset acquisition or other similar business combination with an operating business. On February 24, 2005, Aldabra consummated



its initial public offering of 8,000,000 units with each unit consisting of one share of common stock and two warrants; each warrant holder has the right to purchase one share of common stock at an exercise price of $5.00 per share. On February 25, 2005, Aldabra consummated the closing of an additional 1,200,000 units subject to the over-allotment option. The units were sold at an offering price of $6.00 per unit, generating total gross proceeds of $55,200,000. After deducting the underwriting discounts and commissions and the offering expenses, the total net proceeds from the offering were approximately $50,835,000, of which approximately $49,336,000 were deposited into a trust fund and the remaining proceeds were available to be used to provide for business, legal and accounting due diligence on prospective business combinations, general and administrative expenses and corporate income and franchise taxes. The net proceeds deposited into the trust fund remain on deposit in the trust fund earning interest and will not be released until the earlier of the consummation of a business combination or the liquidation of Aldabra. As of October 1, 2006, the value of the trust fund amounted to approximately $52,020,800,$52,020,834, and such funds were invested in Federated 825 NY Muni Cash Trust, earning approximately 3.48%. Aldabra is not presently engaged in, and will not engage in, any substantive commercial business until the consummation of a business combination. The units, common stock and warrants of Aldabra are traded on the Over-the-Counter Bulletin Board under the symbols ALBAU.OB, ALBA.OB and ALBAW.OB, respectively. If the proposals are not approved, and the Great Lakes merger and the holding company merger are not consummated by February 24, 2007, Aldabra will not have the ability to complete a different business combination by February 24, 2007, and Aldabra's Board of Directors will recommend to the Aldabra stockholders the dissolution of Aldabra and the distribution to all holders of IPO Shares, in proportion to the number of such shares held by them, an aggregate sum equal to the amount in the trust fund, inclusive of any interest. Aldabra's executive offices are located at c/o Terrapin Partners LLC, 540 Madison Avenue, 17th Floor, New York, NY 10022. Aldabra files reports with the SEC, which are available free of charge atwww.sec.gov. Aldabra Acquisition Corporation is sometimes referred to in this proxy statement/prospectus as "Aldabra." See "Information about Aldabra Acquisition Corporation."

        Aldabra Merger Sub, L.L.C.    Aldabra Merger Sub, L.L.C. is a newly-formed Delaware limited liability company into which Great Lakes will merge pursuant to the terms of the merger agreement, with Aldabra Merger Sub, L.L.C. being the surviving company. Aldabra Merger Sub, L.L.C. is a direct, wholly-owned subsidiary of Aldabra. Aldabra Merger Sub, L.L.C. is sometimes referred to in this proxy statement/prospectus as "Merger Sub."

        Great Lakes Dredge & Dock Holdings Corp.    Great Lakes Dredge & Dock Holdings Corp. is a newly-formed Delaware corporation and the parent of GLH Merger Sub, L.L.C., a Delaware limited liability company into which Aldabra will merge pursuant to the holding company merger. Great Lakes Dredge & Dock Holdings Corp. is presently a direct, wholly-owned subsidiary of Aldabra. Great Lakes Dredge & Dock Holdings Corp. is sometimes referred to in this proxy statement/prospectus as "Great Lakes Holdings."

        GLH Merger Sub, L.L.C.    GLH Merger Sub, L.L.C. is a newly-formed Delaware limited liability company into which Aldabra will merge pursuant to the holding company merger. GLH Merger Sub, L.L.C. is the subsidiary of Great Lakes Dredge & Dock Holdings Corp.


        The following chart shows the current corporate structure of the parties to the Great Lakes merger and the holding company merger:

GRAPHIC

The Great Lakes merger

        At the special meeting, Aldabra's stockholders will be asked to approve the merger of Great Lakes with and into Merger Sub, with Merger Sub surviving the merger and Great Lakes stockholders receiving shares of common stock of Aldabra, pursuant to the terms of the merger agreement.

        The following chart shows the resulting corporate structure after the Great Lakes merger:

GRAPHIC


(1)
Pursuant to the Great Lakes merger, GLDD Acquisitions Corp. merges with and into Aldabra Merger Sub, L.L.C.

(2)
In consideration for the Great Lakes merger, Aldabra Acquisition Corporation issues shares of common stock to the stockholders of GLDD Acquisitions Corp.

        The merger consideration, which is the number of shares of Aldabra common stock to be issued to the Great Lakes stockholders in the Great Lakes merger, will consist of a base consideration of $160,000,000 in shares of Aldabra common stock (but will not in any event be less than 27,273,000 shares) and an incremental consideration (positive or negative, not to exceed 7,500,000 shares) based on the amounts, as of the end of the day before the closing, by which (i) Great Lakes' net indebtedness is greater or less than $250,000,000, (ii) Great Lakes' net working capital is greater or less than $47,097,000, and (iii) Aldabra's net working capital is less than $50,000,000. The exchange ratio will be based on the average closing price of Aldabra common stock for the ten trading days ending three trading days prior to the consummation of the Great Lakes merger. The exact number of shares to be delivered in the Great Lakes merger is not determinable at this time, since the exchange ratio used to calculate the number of shares of Aldabra common stock to be delivered is not yet known and since



the number of shares of Aldabra common stock that will be issued will vary based on working capital and indebtedness adjustments, but in no event will the aggregate number of shares of Aldabra common stock issuable to Great Lakes stockholders exceed 40,000,000 shares.

        The following chart sets forth the percentages of Great Lakes Holdings common stock that will be owned by Aldabra stockholders and Great Lakes stockholders, respectively, following consummation of the mergers based on a range of average trading prices of Aldabra common stock. These percentages assume that no Aldabra stockholders exercise their conversion rights, that no outstanding warrants are exercised and that no working capital or indebtedness adjustment is made.


 Average Trading Price
  Average Trading Price
 

 $5.10
 $5.20
 $5.30
 $5.40
 $5.50
 $5.60
 $5.70
 $5.80
 $5.87 or
higher

  $5.10(1)
 $5.20
 $5.30
 $5.40
 $5.50
 $5.60
 $5.70
 $5.80
 $5.87(2) or
higher

 
Aldabra stockholders 26.3%26.7%27.1%27.4%27.8%28.2%28.5%28.9%29.1% 26.3%26.7%27.1%27.4%27.8%28.2%28.5%28.9%29.1%

Great Lakes stockholders

 

73.7

%

73.3

%

72.9

%

72.6

%

72.2

%

71.8

%

71.5

%

71.1

%

70.9

%

 

73.7

%

73.3

%

72.9

%

72.6

%

72.2

%

71.8

%

71.5

%

71.1

%

70.9

%

(1)
Represents the lowest price at which shares of Aldabra common stock have traded since Aldabra's initial public offering.

(2)
Represents the trading price of Aldabra common stock at which the minimum amount of shares required to be issued under the merger agreement would be issued to Great Lakes' stockholders.

        Only by way of example, if the closing of the Great Lakes merger had occurred on August 31, 2006, the average trading price would have been $5.36 per share, and based on Great Lakes' net indebtedness and working capital and Aldabra's working capital, in each case as of August 31, 2006, the merger consideration would have been 29,570,968 shares of Aldabra common stock.calculated as follows:

 
  
  
 
Base consideration    $160,000,000 

Target net indebtedness

 

$

250,000,000

 

 

 

 
Great Lakes' net indebtedness $-256,123,320    
  
    
Adjustment $(6,123,320)   

Great Lakes' net working capital

 

$

51,720,708

 

 

 

 
Target net working capital $-47,097,000    
  
    
Adjustment $4,623,708    

Aldabra's net working capital

 

$

51,492,613

 

 

 

 
Target net working capital $50,000,000    
Adjustment  N/A    

Net adjustment

 

 

 

 

$

(1,499,612

)
     
 
Adjusted base consideration    $158,500,388 
Average trading price     ÷5.36 
     
 
Merger consideration (Aldabra shares issued)     29,570,968 

        The actual number of shares of Aldabra common stock is not determinable at this time and may differ from this example. The exchange ratio will be determined as soon as practicable after the special meeting of Aldabra shareholders. Such determination is expected to occur no later than the day after such special meeting is held.



Amended and Restated Certificate of Incorporation

        In connection with the Great Lakes merger, Aldabra stockholders are also being asked to approve the amendment and restatement of the certificate of incorporation of Aldabra, which involves increasing the number of authorized shares of Aldabra common stock to a number sufficient to satisfy Aldabra's obligations under the Great Lakes merger agreement to issue common stock, but in no event to exceed an additional 40,000,000 shares.

Election of Directors

        In connection with the Great Lakes merger, Aldabra stockholders are also being asked to elect the following persons to serve as directors of Aldabra: Thomas S. Souleles, Douglas S. Grissom, Douglas B. Mackie, Nathan D. Leight, Jason G. Weiss, Jonathan W. Berger, Peter R. Deutsch and one additional independent director to be designated in writing by MDCPBruce J. Biemeck (see "Directors and Executive Officers Following the Mergers—Directors and Executive Officers of Great Lakes Holdings" for information regarding these persons).

        Aldabra's board of directors is divided into three classes, designated Class A, Class B and Class C. The members of the three classes that are proposed to be elected in this proxy statement/prospectus will have initial terms beginning upon completion of the Great Lakes merger and terminating, in the case of Class A directors, on the date of the 2007 annual meeting, in the case of Class B directors, on the date of the 2008 annual meeting and, in the case of Class C directors, on the date of the 2009 annual meeting. At each annual meeting of stockholders of Aldabra, the successors to the class of directors whose terms expire at the meeting will be elected to hold office for a term expiring at the annual meeting of stockholders held in the third year following the year of their election. Each director will hold office for the term to which he or she is elected and until his or her successor is duly elected and qualified.



        Effective upon completion of the Great Lakes merger, the current directors of Aldabra will resign and the new directors elected will be allocated to the three different classes as follows:


The Holding Company Merger

        Aldabra stockholders are also being asked to approve a subsequent merger that will occur not more than one business day following the Great Lakes merger in which Aldabra will merge with and into GLH Merger Sub, L.L.C., an indirect wholly-owned subsidiary of Aldabra. In connection with the holding company merger, Aldabra stockholders (including the former Great Lakes stockholders) will receive common stock of Great Lakes Holdings, a newly formed direct subsidiary of Aldabra. The holding company merger is being effected for the purpose of adopting new transfer restrictions to regulate the ownership of Great Lakes Holdings common stock by persons that are not citizens of the United States for purposes of maritime law. These restrictions are intended to ensure compliance with certain maritime laws that are applicable to Great Lakes' business. See "Description of Great Lakes Dredge & Dock Holdings Corp.'s Capital Stock—Restrictions on Transfer and Ownership."

        The following chart shows the resulting corporate structure after the holding company merger:



GRAPHIC


(1)
Pursuant to the holding company merger, Aldabra Acquisition Corporation merges with and into GLH Merger Sub, L.L.C.

(2)
In consideration for the holding company merger, Great Lakes Dredge & Dock Holdings Corp. issues shares of common stock to stockholders of Aldabra Acquisition Corporation.

        Following the mergers, Great Lakes Holdings intends to merge each of GLH Merger Sub, L.L.C., Aldabra Merger Sub, L.L.C. and Great Lakes Dredge & Dock Corporation into Great Lakes Dredge & Dock Holdings Corp. and to change the name of Great Lakes Dredge & Dock Holdings Corp. to Great Lakes Dredge & Dock Corporation.


Recommendation of Aldabra's Board of Directors

        Aldabra's board of directors:

Reasons for the Recommendation

        Aldabra was formed to effect a merger, capital stock exchange, asset acquisition or other similar business combination with an operating business. On June 20, 2006, Aldabra entered into an agreement and plan of merger pursuant to which Great Lakes will merge into a wholly-owned subsidiary of Aldabra. Great Lakes, through its operating subsidiary, is the largest provider of dredging services in the United States, approximately 85% of the equity of which is owned by affiliates of Madison Dearborn. Aldabra's proposed acquisition of Great Lakes is intended to be a qualifying "business combination" under Aldabra's certificate of incorporation.

        Aldabra's board considered many factors in connection with its evaluation of the proposed merger with Great Lakes. These factors included an extensive evaluation of numerous positive and negative factors, and strengths and weaknesses of Great Lakes' business and the dredging industry.

        In considering the Great Lakes merger and reaching its recommendations, the Aldabra board consulted with Aldabra's management and its legal and financial advisors, and gave considerable weight to the following factors, with respect to business, financial, structural and certain other factors:






        In view of the wide variety of factors considered in connection with its evaluation of the Great Lakes merger and the complexity of these matters, the Aldabra board of directors did not find it useful to, and did not attempt to quantify, rank or otherwise assign relative weights to these factors.

        In addition, the Aldabra board of directors did not undertake to make any specific determination as to whether any particular factor, or any aspect of any particular factor, was favorable or unfavorable to its ultimate determination, but rather the Aldabra board of directors conducted an overall analysis of the factors described above, including discussions with Aldabra's management and outside legal and financial advisors. In considering the factors described above, individual members of the Aldabra board of directors may have given different weight to different factors.

        There is no assurance that any of these factors will in fact result in an increase in stockholder value for Aldabra stockholders after the consummation of the Great Lakes merger.

        Additionally, there are certain risks relating to the transactions that could materially adversely affect stockholder value. Some of the risks involved include: (i) 


        See "Risk Factors" and "Cautionary Statement Concerning Forward-Looking Statements" for a description of these as well as additional material risks related to Great Lakes' business and the Great Lakes merger.

Certain Financial Projections

        Although Great Lakes periodically may issue limited guidance to investors concerning its expected financial performance, Great Lakes does not as a matter of course publicly disclose detailed financial projections. However, in connection with its confirmatory due diligence, Aldabra requested, and Great Lakes' management provided Aldabra and its financial advisors with, non-public, financial projections prepared by Great Lakes' management in May 2006. A summary of Great Lakes' financial projections is set forth below.

        While the financial projections set forth below were prepared in good faith by Great Lakes' management, no assurance can be given regarding future events. The financial projections are not historical fact and should not be relied upon as being necessarily indicative of future results. The financial projections in this section were not prepared with a view toward public disclosure or with a view toward complying with the guidelines established by the American Institute of Certified Public



Accountants with respect to prospective financial information or published guidelines of the SEC regarding forward-looking statements. In light of the foregoing, and considering that the Aldabra stockholder meeting will be held at least six months after the date the financial projections included below were prepared, as well as the uncertainties inherent in any financial projections, stockholders are cautioned not to rely onkeep these facts in mind and to understand that the information contained in this Proxy Statement/Prospectus under the header "Cautionary Statement Concerning Forward-Looking Statements" apply particularly to these financial projections. These projections are not included in this document in order to induce any Aldabra stockholder to vote in favor of authorizing the issuance of shares required to be issued to GLDD stockholders pursuant to the merger agreement, or any Aldabra stockholder to vote to approve the merger agreement, or to impact any investment decision with respect to Aldabra common stock. For a description of the assumptions underlying these projections, the methodology used and the limitations involved with projections, see "The Merger—Certain Financial Projections." Great Lakes has not updated and does not intend to update or otherwise revise these projections to reflect circumstances existing since their preparation or to reflect the occurrence of unanticipated events even in the event that any or all of the underlying assumptions are shown to be in error.



Great Lakes' Summary Financial Projections
(all amounts are approximate)

 
 Forecast
 Projected
Valuation Method

 2006
 2007
 2008
 
 ($s in millions)

EBITDA(1) $50 $57 $58
Adjusted EBITDA(2)  52.5  57.9  62.4
Interest Expense  18.6  16.6  16.6
Capital Expenditures  14.5  14.5  14.5
Operating Lease Buyouts  3.8  13.1  0.6

(1)
Defined as net income (loss) before net interest expense, income taxes, depreciation and amortization expense.

(2)
EBITDA is adjusted in 2006 to add back $0.5 million of expenses related to Great Lakes' response to a federal subpoena relating to an investigation of the dredging industry (see "Information about GLDD Acquisitions Corp.—Legal Proceedings") and $2.0 million of expense relating to Great Lakes' increase in its self-insurance reserve for personal injury claims (see footnote 11 to Great Lakes' unaudited financial statements included in this proxy statement/prospectus). Adjusted EBITDA for each of 2007 and 2008 is further adjusted to add back lease expense assuming an anticipated exercise of early buy-out options related to certain operating equipment currently under long-term operating lease arrangements of $0.9 million and $4.4 million, respectively. See "Information about GLDD Acquisitions Corp.—Management's Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and Capital Resources."

Opinion of Financial Advisor

        BearingPoint Capital LLC rendered its oral opinion, which was subsequently confirmed in writing to Aldabra's Board of Directors to the effect that, as of June 19, 2006, based upon and subject to the assumptions made, matters considered, and limitations on its review as set forth in the opinion, (i) the merger consideration is fair, from a financial point of view, to Aldabra's stockholders, and (ii) the fair market value of Great Lakes is at least equal to 80% of Aldabra's net assets.

        The full text of BearingPoint Capital LLC's written opinion, dated June 19, 2006, which sets forth, among other things, the assumptions made, procedures followed, matters considered and limitations on



the opinion and the review undertaken in connection with the opinion, is attached as Exhibit C to this proxy statement/prospectus.

Conditions to the Great Lakes Merger

        The Great Lakes merger will be completed only if the conditions specified in the merger agreement are either satisfied or waived (to the extent permissible). Some of the most significant conditions specified in the merger agreement include:









        We cannot assure you that all of the conditions above will be satisfied or waived or that the Great Lakes merger or the holding company merger will occur.



        If the requisite holders of Aldabra common stock approve the Great Lakes merger and the other conditions to the Great Lakes merger are satisfied or waived (to the extent permissible), then the parties intend to consummate the Great Lakes merger and the holding company merger as soon as practicable following the special meeting. We currently anticipate closing the Great Lakes merger in NovemberDecember of 2006.

Interests of Great Lakes' and Aldabra's Directors and Executive Officers in the Merger

        In considering the recommendation of the board of directors of Aldabra to vote in favor of (i) the adoption of the merger agreement and the Great Lakes merger, (ii) the increase in the authorized number of shares of Aldabra common stock, and (iii) the adoption of the subsequent merger agreement and the approval of the holding company merger, stockholders of Aldabra should be aware that members of the Aldabra board of directors and certain of Aldabra's executive officers have arrangements that provide them with interests in the Great Lakes merger that differ from, or are in addition to, those of Aldabra's stockholders generally. During its deliberations in determining to recommend to the stockholders of Aldabra that they vote in favor of the matters described above, the Aldabra board of directors was aware of all such interests.



        Prior to Aldabra's initial public offering, Aldabra's officers and directors (or certain of their affiliates or designees) purchased the following shares of Aldabra common stock:stock at a purchase price of $0.0125 per share:

Nathan D. Leight 944,000 shares
Jason G. Weiss 944,000 shares
Jonathan W. Berger 20,000 shares
Peter R. Deutsch 20,000 shares
Stewart K.P. Gross 20,000 shares
Lyla H. Oyakawa 0 shares
Robert C. Plotkin 0 shares

        As well, at such time, 52,000 shares of common stock were purchased by the Terrapin Partners Employee Partnership.Partnership at a purchase price of $0.0125 per share. Such partnership is managed by Terrapin Partners LLC (of which Mr. Leight and Mr. Weiss are its General Partners and of which Mr. Leight and Mr. Weiss and their affiliates are the sole owner) and the economic interests associated with these shares are owned by a number of different Terrapin Partners LLC employees. Additionally, subsequent to Aldabra's initial public offering, Mr. Leight, Mr. Weiss, Mr. Berger, Ms. Oyakawa and Mr. Plotkin purchased in the open market 19,000, 19,000, 200, 500 and 200 shares of Aldabra common stock, respectively.

        All shares purchased prior to Aldabra's initial public offering are subject to an escrow agreement, and will not be released until the earlier of (i) February 17, 2008, (ii) Aldabra's liquidation, or (iii) the consummation of a liquidation, merger, stock exchange or other similar transaction subsequent to a business combination such as the Great Lakes merger. During the escrow period, the holders of the shares purchased prior to Aldabra's initial public offering are not able to sell their securities, but retain all other rights as stockholders.

        If the Great Lakes merger and the holding company merger are consummated, Aldabra's officers and directors will receive one share of Great Lakes Holdings for each share of Aldabra that they own.

        If the Great Lakes merger is not consummated, Aldabra is required by the terms of its certificate of incorporation to liquidate and distribute the proceeds held in trust to holders of the IPO Shares. In such event:


        Additionally, subsequent to Aldabra's initial public offering, between August 23, 2006 (the date the preliminary proxy statement/prospectus was filed) and November 3, 2006, Mr. Leight, Mr. Weiss, Mr. Berger, Mr. Deutsch, Mr. Gross, Ms. Oyakawa and Mr. Plotkin (and/or their respective family trusts or IRAs) purchased in the open market the following number of shares of Aldabra common stock and units at the following average purchase prices:

 
 Number of Shares/
Units

 Average Price per Share/Unit
Nathan D. Leight 16,000 shares $5.55
  7,000 units $6.44
Jason G. Weiss 22,900 shares $5.52
Jonathan W. Berger 400 shares $5.76
Peter R. Deutsch 1,800 shares $5.70
Steward K.P. Gross 4,000 shares $5.70
Lyla H. Oyawaka 500 shares $5.61
Robert C. Plotkin 200 shares $5.55

        Regulation M does not apply to these purchases. Mr. Leight, Mr. Weiss and the other directors and officers of Aldabra and their affiliates will be entitled to vote any shares acquired by them subsequent to Aldabra's initial public offering as they see fit.

        If the Great Lakes merger and the holding company merger are consummated, Aldabra's officers and directors will receive one share of Great Lakes Holdings for each share of Aldabra that they own.

        Additionally, Terrapin Partners LLC purchased 1,572,000 warrants in the open market (at an average purchase price of $0.65 per warrant) and Mr. Leight (or his affiliates) acquired 14,000 warrants as part of the 7,000 units purchased by him in the open market.market (as previously disclosed). Such warrants will become exercisable upon completion of the Great Lakes merger and each of them will entitle its holder to purchase one share of Great Lakes Holdings common stock at a price of $5.00 per share. However, if the Great Lakes merger is not consummated, the warrants will never become exercisable since Aldabra will be required to liquidate.

        The shares (other than those purchased after Aldabra's initial public offering) and warrants owned by Aldabra's officers and directors will be worthless if Aldabra does not consummate the Great Lakes merger. However, if the mergers are consummated, Aldabra's officers and directors will be entitled to receive shares of the entity resulting from the mergers.

        Only by way of example, below is a table showing the value of the holdings in the entity resulting from the mergers that Aldabra's directors and officers (and affiliates) would have if the mergers are consummated. Such value is calculated assuming three different prices at which the stock of the entity resulting from the mergers trades and is based on the number of Aldabra shares and warrants acquired by Aldabra's directors and officers as described above.


  
 Assumed Trading Price Per Share
  
 Assumed Trading Price Per Share

 Number of Shares or Warrants(1)
 Number of Shares or Warrants(1)

 $5.10
 $5.35
 $5.87
 $5.10
 $5.70
 $5.87
Nathan D. Leight 961,000 shares
14,000 warrants
 $
4,901,100
1,400
 $
5,141,350
4,900
 $
5,641,070
12,180
 967,000 shares
14,000 warrants
 $
4,931,700
1,400
 $
5,511,900
9,800
 $
5,676,290
12,180
Jason G. Weiss 963,000 shares 4,911,300 5,152,050 5,652,810 966,900 shares 4,931,190 5,511,330 5,675,703
Jonathan W. Berger 20,200 shares 103,020 108,070 118,574 20,400 shares 104,040 116,280 119,748
Peter R. Deutsch 20,000 shares 102,000 107,000 117,400 21,800 shares 111,180 124,260 127,966
Stewart K.P. Gross 20,000 shares 102,000 107,000 117,400 24,000 shares 122,400 136,800 140,880
Lyla H. Oyakawa 500 shares 2,550 2,675 2,935 500 shares 2,550 2,850 2,935
Robert C. Plotkin 200 shares 1,020 1,070 1,174 200 shares 1,020 1,140 1,174
Terrapin Partners Employee Partnership 52,000 shares 265,200 278,200 305,240 52,000 shares 265,200 296,400 305,240
Terrapin Partners LLC 1,572,000 warrants $157,200 $550,200 $1,367,640 1,572,000 warrants 157,200 1,100,400 1,367,640

(1)
The value of the warrants stated above only includes the intrinsic value (taking into account the $5.00 exercise price that the holder of the warrants would have to pay for each share of the entity resulting from the mergers) and does not include the so-called "option value" of the warrants (as is commonly referred to when valuing warrants).

        For a discussion of the ownership of Aldabra common stock and warrants by its directors and executive officers, see "Information About Aldabra Acquisition Corporation".

        The merger agreement provides that Nathan Leight, Jason Weiss, Jonathan Berger and Peter Deutsch, who are all current directors of Aldabra, will be directors of Great Lakes Holdings. Following the mergers, directors that are neither employees of Great Lakes Holdings or GLDD investors prior to the mergers may receive fees. Aldabra has not established a formal policy for compensating directors. However, the founders of Terrapin Partners LLC and Madison Dearborn have agreed to not be paid



for as long as Madison Dearborn controls Aldabra. Aldabra's directors and executive officers will also have the right to continued indemnification and insurance coverage by the surviving corporation for acts or omissions occurring before the Great Lakes merger.



        Nathan Leight and Jason Weiss hold interests in MDCP of approximately 0.0125% and 0.025%, respectively, which give them indirect holdings in Great Lakes. Such interests stem from Nathan Leight's $500,000 capital commitment in MDCP and Jason Weiss' $1,000,000 capital commitment in MDCP. Based on MDCP's investment in Great Lakes, and Mr. Leight's and Mr. Weiss' pro rata ownership level in MDCP, Mr. Leight and Mr. Weiss collectively have an indirect investment in Great Lakes of approximately $38,000, prior to giving effect to the Great Lakes merger.

        Nathan Leight and Jason Weiss, and/or family trusts affiliated with them, currently intend to purchase a material number of securities of Aldabra in the open market in the time period between the filing of this registration statement and the mailing of this proxy statement/prospectus to Aldabra stockholders. Between August 23, 2006, the date the preliminary proxy statement/prospectus was filed, and                        , 2006, the date of the mailing of the definitive proxy statement/prospectus to stockholders, Mr. Leight and Mr. Weiss acquired 19,000 and 19,000 shares of Aldabra common stock, respectively, and 14,000 and 0 Aldabra warrants, respectively. Regulation M does not apply to these purchases. Mr. Leight, Mr. Weiss and the other directors and officers of Aldabra and their affiliates will be entitled to vote any shares acquired by them subsequent to Aldabra's initial public offering as they see fit.

These personal and financial interests of Aldabra's officers and directors may have influenced their motivation in identifying and selecting Great Lakes as a merger partner and entering into the merger agreement. Consequently, Aldabra's officers and directors may have had a conflict of interest when determining whether the terms, conditions and timing of the merger combination are appropriate and in Aldabra's stockholders' best interests.

U.S. Federal Income Tax Consequences of the Great Lakes Merger and the Holding Company Merger

        Sidley Austin LLP,AustinLLP, legal counsel to Aldabra, has delivered its opinion which provides that (a) the Great Lakes merger will be treated for U.S. federal income tax purposes as a "reorganization" within the meaning of Section 368 of the Code and, with respect to the Great Lakes merger, that each of Aldabra and Great Lakes will be a "party to a reorganization" within the meaning of Section 368 of the Code, (b) the holding company merger will be treated for U.S. federal income tax purposes as a "reorganization" within the meaning of Section 368 of the Code and, with respect to the holding company merger, each of Aldabra and Great Lakes Holdings will be a "party to a reorganization" within the meaning of Section 368 of the Code, (c) the subsequent mergers of Merger Sub and GLH Merger Sub, L.L.C. with and into Great Lakes Holdings will not constitute transactions and will be disregarded for U.S. federal income tax purposes, and (d) the GLDD Merger will either be treated as a complete liquidation to which Section 332 of the Code applies or as a "reorganization" within the meaning of Section 368 of the Code and, with respect to the GLDD Merger and to the extent the GLDD Merger is treated as a "reorganization" (and not a complete liquidation to which Section 332 of the Code applies), each of Great Lakes Dredge & Dock Corporation and Great Lakes Holdings will be a "party to a reorganization" within the meaning of Section 368 of the Code.

        Assuming thatBased on the foregoing opinions, are correct, a holder of shares of Great Lakes stock will not recognize any gain or loss upon the exchange of the holder's shares of Great Lakes stock for Aldabra common stock pursuant to the Great Lakes merger, except that gain or loss will be recognized on the receipt of cash in lieu of a fractional share of Aldabra common stock. In addition, assuming that the foregoing opinions are correct, a holder of shares of Aldabra common stock (including a holder of shares of Aldabra common stock who received such shares in exchange for shares of Great Lakes stock in the Great Lakes merger) will not recognize any gain or loss upon the exchange of the holder's shares of Aldabra common stock for shares of Great Lakes Holdings common stock pursuant to the holding company merger.



        You should read carefully the discussion under the heading "U.S. Federal Income Tax Considerations" beginning on page 86 of this proxy statement/prospectus. The U.S. federal income tax consequences described above may not apply to some holders of shares of Great Lakes stock or Aldabra common stock, including some types of holders specifically referred to on page 86 of this proxy statement/prospectus.



Accounting Consideration

        The merger of Great Lakes and Aldabra will be accounted for as a recapitalization of Great Lakes. Because Aldabra is not an operating company and Great Lakes will have control of the merger entity, the Great Lakes merger is treated as the issuance of shares of Great Lakes for the net tangible assets of Aldabra (consisting principally of cash) and no goodwill will be recorded in connection with the Great Lakes merger. After the merger, the financial statements of Great Lakes will be presented for all periods and the financials of Aldabra will no longer be presented.

Fees and Expenses

        Aldabra estimates that it will incur, and will be responsible for paying, transaction-related fees and expenses, consisting primarily of filing fees, fees and expenses of investment bankers, attorneys and accountants and other related charges, totaling approximately $1.9 million assuming the mergers and the other transactions contemplated by the merger agreement are completed.

Regulatory Approvals

        Completion of the Great Lakes merger requires that we submit filings under Hart-Scott-Rodino Antitrust Improvements Act of 1976 and satisfy certain waiting periods.

Who Can Answer Other Questions

        If you have any questions about the mergers or the other transactions contemplated by the merger agreement or, if you are an Aldabra stockholder, how to submit your proxy or would like additional copies of this proxy statement/prospectus, you should contact Aldabra's proxy solicitor:

GRAPHIC

105 Madison Avenue
New York, New York 10010
proxy@mackenziepartners.com
Call Collect: (212) 929-5500
or
Toll-Free (800) 322-2885



QUESTIONS AND ANSWERS ABOUT THE TRANSACTIONS

Q:    Why is the Special Meeting of Stockholders being held?

        

A:
The special stockholders meeting is being held in connection with the proposed acquisition of Great Lakes by Aldabra. This acquisition will be accomplished through the Great Lakes merger.merger through which Aldabra will acquire Great Lakes, the parent company of Great Lakes Dredge & Dock Corporation. In connection with this merger, Aldabra stockholders are being asked to approve an amendment to Aldabra's charter to increase the number of authorized shares of common stock to a number sufficient to satisfy Aldabra's obligations under the merger agreement (but not to exceed an additional 40,000,000 shares) and to approve the appointment of eight new directors. Aldabra stockholders are also being asked to approve the holding company merger, which will occur promptly following the Great Lakes merger.merger in which Aldabra will merge with a subsidiary of Great Lakes Holdings and, after as a series of parent-subsidiary mergers, Great Lakes Holding will be the sole surviving company and will be renamed Great Lakes Dredge & Dock Corporation. In connection with the holding company merger, Aldabra stockholders (including the former Great Lakes stockholders) will receive common stock of Great Lakes Holdings.

Q:    Why is Aldabra proposing the merger with Great Lakes?

A:
Aldabra was formed to effect a merger, capital stock exchange, asset acquisition or other similar business combination with an operating business. On June 20, 2006, Aldabra entered into an agreement and plan of merger pursuant to which Great Lakes will merge into a wholly-owned subsidiary of Aldabra. Great Lakes, through its operating subsidiary, is the largest provider of dredging services in the United States, approximately 85% of the common equity of which is owned by affiliates of Madison Dearborn.

Q:    What are Great Lakes stockholders being asked to vote upon?

A:
Great Lakes stockholders are not being asked to vote upon the proposals. Delaware law allows stockholders to act by written consent instead of holding a meeting. Great Lakes stockholders owning a majority of the outstanding Great Lakes common stock have signed a written consent adopting and approving the merger agreement and the proposed Great Lakes merger. Therefore, no further vote is required on the part of the Great Lakes stockholders. We are not asking for a proxy from the Great Lakes stockholders, and the Great Lakes stockholders are requested not to send us a proxy.

Q:    How do Aldabra's directors and officers intend to vote their shares?

        

A:
All Aldabra insiders who purchased shares of Aldabra common stock prior to Aldabra's initial public offering, consisting of Aldabra's entire Board of Directors, have agreed to vote their shares of common stock owned by them immediately prior to the initial public offering (the "Private Shares") in accordance with the majority of the votes cast by holders of shares issued in Aldabra's initial public offering (the "IPO Shares"). If holders of a majority of the IPO Shares voting in person or by proxy at the meeting vote for or against, or abstain with respect to, the Great Lakes merger proposal, the holders of the Private Shares will cast all their Private Shares in the same