Exhibit 5.1


                                                      August ____, 1999



Westbank Corporation
225 Park Avenue
West Springfield, Massachusetts 01089-3326

Ladies and Gentlemen:

     We have acted as counsel to Westbank Corporation, a Delaware corporation
(the "Company"), and Westbank Capital Trust I, a Delaware business trust (the
"Trust"), in connection with the preparation of the Registration Statement on
Form S-2 (the "Registration Statement") filed by the Company and the Trust with
respect to the registration under the Securities Act of 1933, as amended (the
"Act"), of (i) up to $1,700,000 of the Trust's Capital Securities, liquidation
amount of $10.00 per capital security (the "Capital Securities"), (ii) the
guarantee by the Company of the Capital Securities, with respect to
distributions and payments upon liquidation, redemption and otherwise (the
"Guarantee") and (iii) up to $17,000,000 principal amount of Junior Subordinated
Deferrable Interest Debentures due 2029 (the "Junior Subordinated Debentures")
to be issued by the Company. In rendering the opinions set forth below, we do
not express any opinion concerning law other than the federal law of the United
States and the corporate law of the State of Delaware.

     In connection with these opinions, we have reviewed originals or copies,
certified or otherwise identified to our satisfaction, of the following
documents:

     (i) the Registration Statement, as filed by the Company and the Trust with
the Securities and Exchange Commission (the "Commission") on August 26, 1999, as
amended;

     (ii) the certificate of trust of the Trust filed with the Secretary of
State of the State of Delaware on August 25, 1999;

     (iii) the form of Amended and Restated Declaration of Trust (the
"Declaration"), by and among Wilmington Trust Company, as property trustee (the
"Property Trustee"), Wilmington Trust Company, as Delaware trustee, the Company,
as sponsor, and, Donald R. Chase, Gary L. Briggs and John M. Lilly as
administrative trustees;


Westbank Corporation
August __, 1999                                                      Page 2.



     (iv) the form of certificate evidencing the Capital Securities;

     (v) the form of Indenture (the "Indenture"), by and between Wilmington
Trust Company, as indenture trustee, and the Company pursuant to which the
Company will issue the Junior Subordinated Debentures;

     (vi) the form of certificate evidencing the Junior Subordinated Debentures;

     (vii)     the form of Guarantee;

     (viii)    the Certificate of Incorporation, as amended, and the Bylaws, as
amended, of the Company; and

     (ix) resolutions adopted by the Board of Directors of the Company in
connection with the issuance of the Guarantee and the Junior Subordinated
Debentures.

     We have also examined originals or copies, certified or otherwise
identified to our satisfaction, of such other documents, corporate records and
other instruments, and have examined such matters of law, as we have deemed
necessary or advisable for purposes of rendering the opinions set forth herein.
As to matters of fact, we have examined and relied upon the information relating
to Company and the Trust contained in the Registration Statement and, where we
have deemed appropriate, representations or certificates of officers or other
representatives of the Company and the Trust, the trustees and public officials.
We have assumed the authenticity of all documents submitted to us as originals,
the genuineness of all signatures, the legal capacity of natural persons and the
conformity to the originals of all documents submitted to us as copies.  In
making our examination of any documents, we have assumed that all parties other
than the Company and the Trust had the corporate power and authority to enter
into and perform all obligations thereunder, and, as to such parties, we have
also assumed the due authorization by all requisite action, the due execution
and delivery of such documents and the validity and binding effect and
enforceability thereof.

     Based on the foregoing, and subject to the limitations, qualifications,
exceptions and assumptions set forth herein, we are of the opinion that:

     1.  The Capital Securities have been duly authorized, and, when (i) the
Declaration and the Indenture have been duly executed and delivered and
qualified under the Trust Indenture Act of 1939, as amended (the "Trust
Indenture Act"), and (ii) the Capital Securities are issued and sold in
accordance with the Registration Statement and the Declaration, the Capital
Securities will be fully paid and non-assessable undivided beneficial interests
in the assets of the Trust, subject to the qualifications set forth in this and
in the following paragraph, and entitle the holders thereof to the benefits of
the Declaration, except as rights to indemnity and contribution thereunder may
be limited under applicable law, and subject to the qualifications that
(a) enforcement thereof may be limited by bankruptcy, insolvency, receivership,
reorganization, liquidation, voidable preference, moratorium or other laws
(including the laws of fraudulent conveyance and transfer) or judicial


Westbank Corporation
August __, 1999                                                     Page 3.


decisions affecting the enforcement of creditors' rights generally or the
reorganization of financial institutions and (b) the enforceability of the
Trust's obligations thereunder is subject to general principles of equity
(regardless of whether such enforceability is considered in a proceeding in
equity or at law) and to the effect of certain laws and judicial decisions upon
the availability and enforceability of certain remedies, including the remedies
of specific performance and self-help.

     The holders of the Capital Securities will be entitled to the same
limitation of personal liability extended to stockholders of private
corporations for profit organized under the General Corporation Law of the State
of Delaware.  The holders of the Capital Securities may be obligated, pursuant
to the Declaration, to (a) provide indemnity and/or security in connection with,
and pay taxes or governmental charges arising from, transfers of Capital
Securities and the issuance of replacement Capital Securities and (b) provide
security and indemnity in connection with requests of or directions to the
Property Trustee to exercise its rights and powers under the Declaration.

     2.  The Guarantee has been duly authorized, and, when (i) the Declaration
and the Indenture have been duly executed and delivered and qualified under the
Trust Indenture Act and (ii) the Guarantee is issued by the Company as
contemplated in the Registration Statement, the Guarantee will constitute a
valid and binding agreement of the Company in favor of the holders of the
Capital Securities, enforceable against the Company in accordance with its
terms, except as rights to indemnity and contribution thereunder may be limited
under applicable law, and subject to the qualifications that (a) enforcement
thereof may be limited by bankruptcy, insolvency, receivership, reorganization,
liquidation, voidable preference, moratorium or other laws (including the laws
of fraudulent conveyance and transfer) or judicial decisions affecting the
enforcement of creditors' rights generally or the reorganization of financial
institutions, and (b) the enforceability of the Company's obligations thereunder
is subject to general principles of equity (regardless of whether such
enforceability is considered in a proceeding in equity or at law) and to the
effect of certain laws and judicial decisions upon the availability and
enforceability of certain remedies, including the remedies of specific
performance and self-help.

     3.  The Junior Subordinated Debentures have been duly authorized, and, when
(i) the Declaration and the Indenture have been duly executed and delivered and
qualified under the Trust Indenture Act and (ii) the Junior Subordinated
Debentures are issued and sold in accordance with the Registration Statement and
the Indenture, the Junior Subordinated Debentures will constitute valid and
binding obligations of the Company, enforceable against the Company in
accordance with their terms, except as rights to indemnity and contribution
thereunder may be limited under applicable law, and subject to the
qualifications that (a) enforcement thereof may be limited by bankruptcy,
insolvency, receivership, reorganization, liquidation, voidable preference,
moratorium or other laws (including the laws of fraudulent conveyance and
transfer) or judicial decisions affecting the enforcement of creditors' rights
generally or the reorganization of financial institutions, and (b) the
enforceability of the Company's obligations thereunder is subject to general
principles of equity (regardless of whether such enforceability is considered in
a proceeding in equity or at law) and to the effect of certain laws and judicial
decisions upon the availability and enforceability of certain remedies,
including the remedies of specific performance and self-help.


Westbank Corporation
August __, 1999                                                       Page 4.

     In rendering the opinions set forth above, we have not passed upon and do
not purport to pass upon the application of securities or "blue-sky" laws of any
jurisdiction (except federal securities laws).

     This opinion is given solely for the benefit of the Company, the Trust and
investors who purchase the Capital Securities pursuant to the Registration
Statement and may not be relied upon by any other person or entity, nor quoted
in whole or in part, or otherwise referred to in any document without our
express written consent.

     We consent to the filing of this opinion as an Exhibit to the Registration
Statement. We also consent to the reference to our firm under the heading
"Validity of Securities" in the Prospectus which forms a part of the
Registration Statement.

                                    Very truly yours,

                                    Thacher Proffitt & Wood



                                    By:____________________________