EXHIBIT 10.9(A)

I, the undersigned, Sworn Public Translator and Commercial Interpreter in and
for this City and State of Rio de Janeiro, Federative Republic of Brazil,
registered at the Commercial Board of Rio de Janeiro under Number 97, do hereby
CERTIFY and ATTEST that a document in the Portuguese Language was submitted to
me for translation into English, which I performed according to my Office, as
follows:

                             Translation No. 2674/98

 (On paper with letterhead of PETROBRAS.)

      RIDER No. 01 TO CONTRACT 101.2.100.97-8, ENTERED INTO BETWEEN MARITIMA
      PETROLEO E ENGENHARIA LTDA., SUCCESSOR OF MARITIMA NAVEGACAO E ENGENHARIA
      LTDA., and PETRODRILL FIVE LTD., WITH THE CONSENT OF PETROLEO BRASILEIRO
      S.A. - PETROBRAS.

      PETROLEO BRASILEIRO S.A. - PETROBRAS, a mixed economy company, with head
office at Av. Republica do Chile 65, in the City of Rio de Janeiro, State of Rio
de Janeiro, Federative Republic of Brazil, enrolled in the General Taxpayers
Registry of the Ministry of Finance under No. 33.000.167/0001-01, henceforth
called PETROBRAS, represented herein by the Executive Superintendent of
Exploration and Production, Luiz Eduardo G. Carneiro, and the Company MARITIMA
PETROLEO E ENGENHARIA LTDA., successor of MARITIMA NAVEGACAO E ENGENHARIA LTDA.,
with head office at Av. Almirante Barroso, 52, 34th floor, City of Rio de
Janeiro, Federative Republic of Brazil, enrolled in the General Taxpayers
Registry of the Ministry of Finance under No. 46.828.596/0001/13, henceforth
called the ASSIGNOR, represented herein by its President, German Efromovich, and
the company PETRODRILL FIVE LTD., with head office in Omar Hodge Building,
Wickhams Cay, Road Town, Tortola, Ilhas Virgens Britanicas, henceforth


called the ASSIGNEE, represented herein by its Director, German
Efromovich, have agreed to add a rider to contract 101.2.100.97-8 (AMETHYST 5),
according to the following, clauses and conditions: FIRST CLAUSE - OBJECT.

1.1.   The present Rider has as its object:

1.1.1. The total assignment, as of the date of the signature of this Rider,
       henceforth called the ASSIGNMENT DATE, by the ASSIGNOR to the ASSIGNEE of
       the rights and obligations arising from Contract No. 101.2.100.97-8 and
       its Attachments.

1.1.2. To change the contract value foreseen in item 5.2 of the Fifth Clause -
       PRICES AND VALUE.

1.1.3. To change the redaction of the Seventh Clause - FORM OF PAYMENT.

1.1.4. To change the Fourth Clause - PETROBRAS' OBLIGATIONS, including item
       4.12.

SECOND CLAUSE - RESPONSIBILITY.

2.1.   The ASSIGNEE, as of the ASSIGNMENT DATE, becomes the CONTRACTOR, being
       liable, before PETROBRAS for the fulfillment of all contract obligations
       undertaken by the ASSIGNOR, and will also have all rights arising from
       the Contract.

2.2.   The ASSIGNEE is liable before PETROBRAS for the fulfillment of all
       contract obligations undertaken by the ASSIGNOR in the Contract, as well
       as for eventual losses and damages arising from its acts or omissions.

2.3.   The ASSIGNOR will be jointly liable with the ASSIGNEE for the complete
       fulfillment of all obligations arising from the Contract.

2.4.   The ASSIGNOR, as of the ASSIGNMENT DATE, will have no right arising from
       the Contract, giving PETROBRAS, full and complete acquittance for any and
       all contract value.



THIRD CLAUSE - PRICES AND VALUE.

3.1.   The redaction of item 5.2 and its subitems becomes: 5.2. The total
       estimated value of the present Contract becomes US$223,719,698.40 (two
       hundred and twenty-three million, seven hundred and nineteen thousand,
       six hundred and ninety-eight American dollars and forty cents),
       equivalent to R$ 238,485,198.49 5.2.1. Chartering of the UNIT:
       US$217,239,765.00; 5.2.2. Mobilization: US$6,479,933.40.

3.2.   Item 5.5 is included with the following redaction: "5.5. Besides the
       value mentioned in 5.2, the appropriation of US$100,000.00 is foreseen
       for the payment of eventual reimbursements".

FOURTH CLAUSE - PETROBRAS' OBLIGATIONS.

4.1.   Item 4.12 is included, with the following redaction: "4.12. To adopt the
       measures necessary for the request to register this Contract at the
       Central Bank of Brazil, immediately after the receipt of the legal
       documents, the supply of which is the CONTRACTOR'S responsibility."

FIFTH CLAUSE - FORM OF PAYMENT.

5.1.   The redaction of the Seventh Clause is changed to:

       "7.1.  The payments of the rates foreseen in Attachment II and Attachment
              III shall be made by PETROBRAS to the CONTRACTOR in American
              Dollars, by bank remittance to a bank account abroad it indicates,
              after the present Contract is registered at the Central Bank of
              Brazil, 30 (thirty) days as of the date of the end of the
              measuring period considered, provided the CONTRACTOR has fulfilled
              the time limits set forth in subitem 6.3.1, for the submittal of
              the collection documents at the docket of


              the Financial Department indicated by PETROBRAS, with exception of
              the provision appearing in subitem 7.2.4.

       7.1.1. For the reimbursable expenses foreseen in this Contract, the
              instructions contained in item 7.4 and their developments should
              be of the Financial Department indicated by PETROBRAS, with
              exception of the provision appearing in subitem 7.2.4.

       7.1.1. For the reimbursable expenses foreseen in this Contract, the
              instructions contained in item 7.4 and their developments should
              be complied with, and the payments will be made in the currency of
              origin of said expenses, within 30 (thirty) days after the
              submittal of the collection documents at the docket of the
              Financial Department indicated by PETROBRAS.

       7.1.2. Collection documents comprise any type of billing, such as:
              Invoice, Invoice with separate Bill of Sale, Service Invoice,
              besides others foreseen in fiscal laws.

       7.1.3. For payment purposes, the CONTRACTOR shall supply the Contract
              Manager, after its signature, the following information:

              a) Bank name and number;
              b) Bank branch name and code;
              c) Bank branch address;
              d) CONTRACTOR'S current account number.

       7.1.3.1. Whenever a billing is submitted with bank information different
              from those indicated in subitem 7.1.3, these changes will only be
              considered if accompanied by a formal communication by the
              CONTRACTOR and shall prevail only for the specific purpose of such
              payment.

       7.2.   The collection documents shall be issued without erasures,
              complying with the


              pertinent laws in force, for submittal at the Financial Department
              indicated in item 7.1 of this Clause, in its original copy,
              accompanied by 1 (one) copy of the respective Measurement Bulletin
              (MB), and/or Reimbursement Document (RD), as the case may be, duly
              appointed by this contract's Manager, containing, obligatorily,
              but not exclusively, the following information:

              a) Number of the collection document;

              b) Place and date of its issuing;

              c) Brief description of the object of this Contract;

              d) Indication of the number and date of this Contract;

              e) Indication of the month/year or period which the collection
                 document refers to;

              f) Number and date of the Measurement Bulletin (MB) and/or
                 Reimbursement Document (RD).

              g) Place of the rendering and/or execution of the chartering. In
                 the event the chartering has been rendered in different
                 locations, its value should be broken down by locations of
                 performance and the period in which it was rendered at each of
                 the locations shall be indicated;

              h) Gross amount of the collection document, by numbers and in
                 writing;

              i) Place for payment purpose, as provided for in subitem 7.1.3 of
                 this Clause;

              j) Signature by the CONTRACTOR'S representative, accredited before
                 PETROBRAS, above his/her name and position typewritten or above
                 the CONTRACTOR'S company stamp identifying him/her; 1) In case
                 of Rider or Letter of Agreement to the Contract which implies

                 in payments, mention its number and date of signature, besides
                 the data above.

        7.2.1. The omission of any of the above mentioned data will cause,
               within 5 (five) working days, the return of the collection
               documents by PETROBRAS' Financial Department.

        7.2.2. If the above situation occurs and in the case the collection
               document shows errors, it will be returned to the CONTRACTOR, and
               the time limits of the payment foreseen in item 7.1 and subitem
               7.1.1 shall be added to the period that becomes necessary for the
               explanation and re-submittal of the collection document.

        7.2.2.1. The above mentioned condition also applies in case the
               collection document is submitted in another department, and not
               as indicated in item 7.1.

        7.2.3. Independent of the data above, the invoices in foreign currency
               shall be also submitted in the Portuguese language, or if issued
               abroad, they shall be notarized at the Brazilian Consulate, under
               which jurisdiction the CONTRACTOR is located, and translated by a
               sworn public translator.

        7.2.4. The CONTRACTOR shall, obligatorily, submit monthly, together with
               the invoice, the payroll of the CONTRACTOR'S Brazilian crew who
               are involved in the chartering object of this Contract, as well
               as with a photocopy of the GRPS (Social Security Payment Slip),
               duly settled and authenticated, with the data identifying the
               entity to whom the service was rendered being obligatorily filled
               out, informing on field 8 of the GRPS (other information)
               PETROBRAS' name and CGC, number, date, and amount of the invoice
               or bill of sale referring to the chartering rendered in the
               month, subitems 8.9, 10.1.15, and 10.1.16 being also complied
               with.

        7.3.   The collection documents referring to reimbursements shall also
               be issued, itemizing,


               individually, the reimbursable expenses, their total amount, such
               itemization also to appear in the respective Reimbursement
               Document (RD).

        7.3.1. The original vouchers of the reimbursable expenses due to the
               CONTRACTOR, by force of the contract instrument, shall be
               previously submitted to the Contract Manager, for checking,
               besides being duly paid for by the respective supplier or service
               rendered, when such is the case.

        7.3.1.1. In the event the original vouchers cannot remain in PETROBRAS'
               possession, copies thereof may be submitted, which shall be
               checked by the Contract Manager, and the following text is to be
               placed on each original document: "COPY SUBMITTED FOR
               REIMBURSEMENT ON (specify date)", followed by the signature and
               identification by name, position and registry number, and the
               original are to be returned to the CONTRACTOR. In the copies that
               are in PETROBRAS' possession, the following text will be placed
               on each document: "CHECKED WITH THE ORIGINAL ON (specify the
               data)" and the Contract Manager will sign, identifying the
               signature by name, position and registry number.

        7.3.1.2. The receipt, duly made formal by PETROBRAS, of any reimbursable
               expense voucher, does not represent the recognition of debt, nor
               the proof that the expense has been made.

        7.3.2. The collection of reimbursable expenses can only be made by means
               of issuing and submittal, by the CONTRACTOR, of the Bill of Sale
               for the equipment and accessories, with the respective
               Reimbursement Document (RD) duly attached thereto, and previously
               approved by the Contract Manager.

        7.3.2.1. The submittal of the collection document mentioned in subitem
               7.3.2, shall


               comply with the provisions appearing in items 7.1 and 7.2 of this
               Clause.

        7.3.2.2. The vouchers shall be the legal documents to explain doubts
               referring to the collections, which shall be settled, as a last
               resort, by PETROBRAS' Disbursement Office, who will be in
               possession of the vouchers approved by PETROBRAS to prepare the
               payment process.

        7.4.   Eventual payments made for more or less by PETROBRAS shall be
               compensated as soon as they are detected, by issuing the
               Debit/Credit Notes, as the case may be.

        7.5.   The amounts corresponding to reimbursable expenses, without
               budget allotment foreseen in this contract instrument, do not
               burden this contract's estimated total, but should, however, be
               foreseen in the Budget Programs of the Executive Superintendence
               of Exploration and Production (E&P).

        7.6.   The collection documents submitted by the CONTRACTOR, as well as
               the final collection document, shall be paid with the deduction
               of amounts that, at any title, under the conditions set forth in
               the contract, or others specially agreed upon, are due to
               PETROBRAS.

        7.7.   The CONTRACTOR agrees that, at PETROBRAS exclusive option, the
               present Contract can be paid by means of third party financing,
               provided the time limits, currency, amounts, and place of
               payment, and the CONTRACTOR'S rights foreseen in this Contract,
               are complied with".

SIXTH CLAUSE - RESPONSIBILITY.

6.1.    The present rider binds the parties as of the date of its signature and
        enters in force as of the ASSIGNMENT DATE.

SEVENTH CLAUSE - RATIFICATION.


7.1.    PETROBRAS, the ASSIGNOR and the ASSIGNEE ratify the terms and conditions
        of the Contract that are not incompatible with the provisions of this
        instrument.

        And being thus agreed, the parties sign the present Rider in 4 (four)
copies of the same tenor and fashion, together with the witnesses below. Rio de
Janeiro, July 10, 1998.

(Signed:) (Illegible) -  Luiz Eduardo G. Carneiro.
Executive Superintendent of Exploration and Production South-Southeast.

PETROLEO BRASILEIRO S.A.
(Signed:) (Illegible) - German Efromovich.
President - MARITIMA PETROLEO E ENGENHARIA LTDA (ASSIGNOR).
(Signed:) (Illegible) - German Efromovich.
Director - PETRODRILL FIVE LTD. (ASSIGNEE)

WITNESSES:
(Signed:) (Illegible) (Rubber stamp:) Jose Joao Afonso Filho - Administrator -
Registry 010979.7.
(Signed:) (Illegible).
      (The rubber stamp and the signature of Jose Joao Afonso Filho appeared on
the first page of the document.)
      (An ititial appeared on all other pages of the document.)

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THESE BEING the precise terms and content of the aforementioned document, I
hereby set my Hand and Seal on this Translation, performed on November 26, 1998
in this City of Rio de Janeiro, Federative Republic of Brazil.

                            /s/ MARCIA BARBOSA SERRA
                            ------------------------
                              Marcia Barbosa Serra
                             Sworn Public Translator