<PAGE>
 
                                                                   EXHIBIT 10.12

                            STOCK EXCHANGE AGREEMENT

          This Stock Exchange Agreement (the "Agreement") is made and entered
into as of May 21, 1997 by and among Friede Goldman International Inc., a
Delaware corporation ("FGII"), HAM Marine, Inc., a Mississippi corporation ("HAM
Marine"), Friede & Goldman, Ltd., a Mississippi corporation ("Friede &
Goldman"), J. L. Holloway ("Holloway"), Carl M. Crawford ("Crawford"), Ronald W.
Schnoor ("Schnoor"), James A. Lowe III ("Lowe") and John F. Alford ("Alford").

                                  WITNESSETH:

          WHEREAS, FGII has been organized to serve as a holding company for HAM
Marine and Friede & Goldman;

          WHEREAS, Holloway, Crawford, Schnoor, Lowe and Alford (the "HAM Marine
Shareholders") are the sole owners of the no par value common stock of HAM
Marine (the "HAM Marine Common Stock");

          WHEREAS, Holloway, Crawford and Schnoor (the "Friede & Goldman
Shareholders") are the sole owners of the common stock, par value $1.00 per
share, of Friede & Goldman (the "Friede & Goldman Common Stock");

          WHEREAS, pursuant to Section 351 of the Internal Revenue Code of 1986,
as amended (the "Code"), each of Holloway, Crawford, Schnoor, Lowe and Alford
(collectively, the "Participants") desire to exchange all of their shares of HAM
Marine Common Stock and Friede & Goldman Common Stock for shares of common
stock, par value $0.01 per share, of FGII (the "FGII Common Stock"), it being
the intent of FGII and each Participant that such exchange of shares pursuant to
this Agreement (the "Stock Exchange") shall satisfy the requirements of such
section;

          WHEREAS, as part of the transaction qualifying under Section 351 of
the Code, it is contemplated that following the Stock Exchange FGII will make a
public offering of FGII Common Stock (the "Public Offering") pursuant to the
Securities Act of 1933, as amended (the "Securities Act");

          NOW, THEREFORE, in consideration of the premises and the mutual
covenants and agreements hereinafter set forth, the parties hereto hereby agree
as follows:
<PAGE>
 
                                   ARTICLE I

                   REPRESENTATIONS, WARRANTIES AND COVENANTS

          Section 1.1.  Representation of FGII.  (a) FGII hereby represents and
warrants to each of the Participants that it is a corporation duly incorporated
under the laws of Delaware and that it has 1,000 shares of its capital stock
issued and outstanding consisting of 1,000 shares of FGII Common Stock issued to
Holloway.

          (b) FGII hereby represents and warrants to each of the Participants
that the shares of FGII Common Stock to be issued pursuant to the Stock
Exchange, when issued in exchange for the shares of HAM Marine Common Stock and
Friede & Goldman Common Stock as set forth in this Agreement, will be duly
issued, fully paid and nonassessable.

          Section 1.2.  Representations of HAM Marine and the HAM Marine
Shareholders. HAM Marine represents and warrants to FGII that HAM Marine is a
corporation duly incorporated under the laws of Mississippi.  HAM Marine and the
HAM Marine Shareholders represent and warrant to FGII that the only shares of
the capital stock issued and outstanding consist of 1,197,604.80 shares of HAM
Marine Common Stock issued to the following persons in the amounts set forth
opposite their names:

 
                                   Number of Shares
                 Shareholders   Issued and Outstanding
                --------------  ----------------------

                   Holloway          958,471.63
                   Crawford          176,947.49
                   Schnoor            47,185.68
                   Lowe               10,000.00
                   Alford              5,000.00
                                   ------------ 
                    Total          1,197,604.80
                                   ============

      Each of the HAM Marine Shareholders represents and warrants to FGII that
the shares set forth opposite his name are owned by such HAM Marine Shareholder
free and clear of all liens, encumbrances, options, calls, voting trusts and
other charges ("Encumbrances"), and no other person has any ownership interest
in such shares.

      Section 1.3.  Representations of Friede & Goldman and the Friede & Goldman
Shareholders.  Friede & Goldman represents and warrants to FGII that Friede &
Goldman is a corporation duly incorporated under the laws of Mississippi.
Friede & Goldman and the Friede & Goldman Shareholders represent and warrant to
FGII that the only shares of the capital stock issued and outstanding consist of
616.90 shares of Friede & Goldman Common Stock issued to the following persons
in the amounts set forth opposite their names:

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<PAGE>
 
                                             Number of Shares     
                    Shareholders          Issued and Outstanding  
                    ------------          ----------------------  

                     Holloway                     500.00          
                     Crawford                      92.29          
                     Schnoor                       24.61          
                                                  ------          
                            Total                 616.90          
                                                  ======           

      Each of the Friede & Goldman Shareholders represents and warrants to FGII
that the shares set forth opposite his name are owned by such Friede & Goldman
Shareholder free and clear of all Encumbrances, and no other person has any
ownership interest in such shares.

      Section 1.4.  Representations of Participants.  (a) Each Participant
represents and warrants that such Participant (i) has the requisite authority to
enter into this Agreement and to perform his obligations under this Agreement,
(ii) he has duly executed and delivered this Agreement, (iii) all filings,
approvals and consents necessary for the execution, delivery and performance of
this Agreement by such Participant have been made or obtained or shall have been
made or obtained prior to the Closing (as defined in Section 4.1 hereof), (iv)
this Agreement, when executed and delivered by such Participant, will be a valid
and binding agreement of such Participant, (v) the execution, delivery and
performance of this Agreement by such Participant and the consummation of the
transactions contemplated hereby by such Participant will not (A) conflict with
or result in a breach of any of the terms and provisions of, or constitute a
default (or an event which with notice or lapse of time, or both, would
constitute a default) or require consent under the terms of any agreement,
instrument, franchise, license or permit to which such Participant is a party or
by which such Participant may be bound or (B) violate or conflict with any
provision of any judgment, decree, order, statute, rule or regulation of any
court or any public, governmental or regulatory agency or body having
jurisdiction over such Participant, and (vi) no consent, approval,
authorization, order, registration, filing, qualification, license or permit of
or with any court or any public governmental or regulatory agency or body having
jurisdiction over such Participant is required for the execution, delivery and
performance of this Agreement and the consummation of the transactions
contemplated hereby, except such as have been obtained or will be obtained by
such Participant prior to the Closing.

      (b) Each Participant acknowledges receipt of (i) a copy of the Certificate
of Incorporation and Bylaws of FGII, (ii) the historical financial statements of
HAM Marine for the three years ended December 31, 1994, 1995 and 1996, (iii) the
historical financial statements of Friede & Goldman for the eleven-month period
ended November 30, 1996, (iv) the pro forma financial statements of FGII for the
year ended December 31, 1996 that give effect to the Stock Exchange as if it had
occurred on January 1, 1996 and (v) certain other information concerning FGII
and the Stock Exchange, and each Participant acknowledges that he received all
information necessary in order to make an informed decision concerning his
participation in the Stock Exchange.

                                      -3-
<PAGE>
 
      (c) Each Participant acknowledges that such Participant has such knowledge
and experience in financial and business matters so that such Participant is
capable of evaluating the merits and risks of an investment in FGII.  Based upon
such Participant's own knowledge, such Participant recognizes the speculative
nature of such an investment.

      (d) Each Participant hereby acknowledges that the issuance of the shares
of FGII Common Stock being acquired or received by such Participant hereunder is
not and will not be registered under the Securities Act.  Each Participant
represents that the shares of FGII Common Stock being acquired or received
hereunder is being acquired or received for such Participant's own account, for
investment purposes only and not with a view for distribution or resale to
others, except as set forth in paragraph (e) below.  Each Participant agrees
that such Participant will not sell or otherwise transfer any shares of FGII
Common Stock being acquired or received hereunder unless such shares of FGII
Common Stock are registered under the Securities Act or unless an exemption from
such registration is available.

      (e) Each Participant has no present plan, intention, arrangement or
understanding to dispose of any of the shares of FGII Common Stock to be
received pursuant to the transactions described in Article III hereof, other
than a sale of shares of FGII Common Stock pursuant to the Registration
Statement to be filed in connection with the Public Offering.

      (f) Each Participant agrees not to sell, transfer, convey, pledge,
encumber or otherwise dispose of such Participant's shares of HAM Marine Common
Stock or shares of Friede & Goldman Common Stock from the date hereof until the
Closing, except with the written consent of FGII or as contemplated by this
Agreement.

      (g) Each Participant consents to the placement of a legend on any
certificate or other document evidencing the shares of FGII Common Stock to be
received hereunder stating that such shares of FGII Common Stock have not been
registered under the Securities Act and setting forth or referring to the
restrictions on transferability and sale hereof.

                                   ARTICLE II

                                 TERMINATION OF
                             STOCKHOLDER AGREEMENTS

      Section 2.1.  Crawford HAM Marine Stock Purchase Agreement.  HAM Marine,
Holloway and Crawford hereby terminate the Stock Purchase Agreement, dated
January 30, 1997, by and among HAM Marine, Holloway and Crawford effective
immediately prior to the consummation of the Stock Exchange.

      Section 2.2.  Schnoor HAM Marine Stock Purchase Agreement.  HAM Marine,
Holloway, Crawford and Schnoor hereby terminate the Stock Purchase Agreement,
dated April 20, 1994, by 

                                      -4-
<PAGE>
 
and among HAM Marine, Holloway, Crawford and Schnoor effective immediately prior
to the consummation of the Stock Exchange.

      Section 2.3.  Lowe HAM Marine Stock Purchase Agreement.  HAM Marine,
Holloway and Lowe hereby terminate the Stock Purchase Agreement, dated January
1, 1997, by and among HAM Marine, Holloway and Lowe effective immediately prior
to the consummation of the Stock Exchange.

      Section 2.4.  Crawford Friede & Goldman Stock Purchase Agreement.  Friede
& Goldman, Holloway and Crawford hereby terminate the Stock Purchase Agreement,
dated May 21, 1997, by and among Friede & Goldman, Holloway and Crawford
effective immediately prior to the consummation of the Stock Exchange.

      Section 2.5.  Schnoor Friede & Goldman Stock Purchase Agreement.  Friede &
Goldman, Holloway and Schnoor hereby terminate the Stock Purchase Agreement,
dated May 21, 1997, by and among Friede & Goldman, Holloway and Schnoor
effective immediately prior to the consummation of the Stock Exchange.

                                  ARTICLE III

                                 STOCK EXCHANGE

      Section 3.1.  Stock Exchange.  Effective immediately prior to the
consummation of the Public Offering, each HAM Marine Shareholder shall exchange
all of his shares of HAM Marine Common Stock and each Friede & Goldman
Shareholder shall exchange all of his shares of Friede & Goldman Common Stock
for the number of shares of FGII Common Stock set forth opposite his name
(collectively, the "Exchange Stock"):

 
                    Stockholders       Number of Shares 
                    ------------       ---------------- 
                                                        
                     Holloway             7,362,979     
                     Crawford             1,359,310     
                     Schnoor                362,481     
                     Lowe                    76,820     
                     Alford                  38,410      


Certificates representing the number of shares of FGII Common Stock set forth
above will be issued to the Participants upon the presentation of certificates
representing the shares of HAM Marine Common Stock and Friede & Goldman Common
Stock to be exchanged therefor.  The exchange of shares of FGII Common Stock for
shares of HAM Marine Common Stock and Friede & Goldman Common Stock shall all
occur simultaneously.

                                      -5-
<PAGE>
 
      Section 3.2.  Cancellation of Previously Issued FGII Common Stock.
Simultaneously with the Stock Exchange specified in Section 3.1 of this
Agreement, all of the 1,000 shares of FGII Common Stock issued to Holloway in
connection with the original organization of FGII shall be canceled.

                                   ARTICLE IV

                                    CLOSING

      Section 4.1.  Closing.  The consummation of the transactions contemplated
by Article II shall occur in the order set forth herein substantially
concurrently and shall close immediately prior to the closing of the Public
Offering at the offices of the Company, unless another place or time is agreed
upon in writing by the Company (the consummation of such transactions is herein
called the "Closing").

      Section 4.2.  Conditions.  The Closing shall be contingent upon
satisfaction of the following conditions:

      (a) An underwriting agreement relating to the Public Offering shall have
been entered into among FGII and a group of underwriters and all conditions
precedent to the consummation of the transactions contemplated thereby shall
have been satisfied.

      (b) All consents and approvals by, or filings with, any governmental
authority, agency or official, or any other person required in connection with
the execution, delivery and performance of this Agreement and the consummation
of the transactions contemplated hereby shall have been received or made and
shall be in full force and effect.

      Section 4.3.  Termination.  In the event that the Closing does not occur
by September 30, 1997 by reason of the failure of any of the conditions set
forth in Section 4.2 hereof to be satisfied, this Agreement shall thereafter
become null and void and have no effect, and no party hereto shall have any
liability to the other parties hereto.

                                   ARTICLE V

                               GENERAL PROVISIONS

      Section 5.1.  Further Assurances.  At any time, and from time to time,
each party will execute such additional instruments and take such action as may
be reasonably requested by any other party to confirm or perfect title to any
shares of HAM Marine Common Stock or Friede & Goldman Common Stock to be
transferred hereunder or otherwise to carry out the intent and purposes of this
Agreement, including, without limitation, giving any consents required under any
applicable agreements affecting the parties necessary to consummate the
transactions specified in this Agreement.

                                      -6-
<PAGE>
 
      Section 5.2.  Waivers.  Any failure on the part of any party hereto to
comply with any of its obligations, agreements, or conditions hereunder may be
waived in writing by the party to whom such compliance is owed.

      Section 5.3.  Entire Agreement.  This Agreement constitutes the entire
agreement between the parties and supersedes and cancels any other agreement,
representation, or communication, whether oral or written, between the parties
hereto relating to the transactions contemplated herein or the subject matter
hereof.

      Section 5.4.  Headings.  The section and subsection headings in this
Agreement are inserted for convenience only and shall not affect in any way the
meaning or interpretation of this Agreement.

      Section 5.5.  Governing Law.  This Agreement shall be construed under and
in accordance with the laws of the State of Delaware without giving effect to
the principles of conflict of laws thereof.

      Section 5.6.  Amendment.  No amendment of this Agreement shall be
effective without the written consent of any party affected adversely thereby.

      Section 5.7.  Counterparts.  This Agreement may be executed simultaneously
in two or more counterparts, each of which shall be deemed an original, but all
of which together shall constitute one and the same instrument.

      Section 5.8.  Notice.  Any notice or other communication given hereunder
shall be deemed sufficient in writing and sent by registered or certified mail,
return receipt requested, or hand delivered and addressed to any party at FGII's
offices at 525 E. Capitol Street, Suite 402, Jackson, Mississippi 39201, or such
other address as may be specified by a party by like notice.  Notices shall be
deemed to have been given on the date of mailing, except notices of change of
address, which shall be deemed to have been given when received.

      Section 5.9.  Successors and Assigns.  This Agreement shall be binding on
the parties hereto and their permitted successors and assigns.  None of the
parties hereto shall assign their rights under this Agreement without the prior
written consent of FGII.

      Section 5.10.  Unenforceable Provisions.  If any provision of this
Agreement is held to be invalid or unenforceable by a court of competent
jurisdiction, in lieu of such invalid provision there shall be added a provision
which is as similar in terms as possible to such invalid provision and which is
valid and enforceable; such invalid provision shall not affect any other
provision of this Agreement, and, as so modified, this Agreement shall remain in
full force and effect.

                                      -7-
<PAGE>
 
      Section 5.11.  Expenses.  FGII shall pay its own and each of the parties'
pre-approved expenses incurred in connection with the transactions specified
herein, other than separate legal, accounting or investment banking counsel
independently retained by a Participant, which shall be for the Participant's
own account.

                                      -8-
<PAGE>
 
      IN WITNESS WHEREOF, the parties have executed this Agreement as of the
date set forth above.

                                 FRIEDE GOLDMAN INTERNATIONAL INC.

                                 By:_______________________________
                                     Name: J. L. Holloway
                                     Title:  President


                                 HAM MARINE, INC.


                                 By:_______________________________
                                     Name: Ronald W. Schnoor
                                     Title:  President


                                 FRIEDE & GOLDMAN, LTD.


                                 By:_______________________________
                                     Name: Bruce Malcolm
                                     Title:  President


                                 __________________________________
                                 J. L. Holloway


                                 __________________________________
                                 Carl M. Crawford


                                 __________________________________
                                 Ronald W. Schnoor


                                 __________________________________
                                 James A. Lowe III


                                 __________________________________
                                 John F. Alford

                                      -9-