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                                                                   Exhibit 10(a)

                             EMPLOYMENT AGREEMENT


     This Employment Agreement ("Agreement") between Tidewater Inc., a Delaware
corporation ("Company"), and William C. O'Malley ("Employee") is effective as of
September 27, 2000 (the "Agreement Date") and supersedes the employment
agreement between the Company and the Employee dated September 19, 1997.

     The Company and the Employee agree as follows:

     1.   Employment Capacity and Term.
          ----------------------------

          (a)  Capacity and Term.  The Employee will serve as the President and
               -----------------
Chief Executive Officer of the Company for the period beginning September 27,
2000 through March 28, 2002. The period from September 27, 2000 through March
28, 2002 is referred to in this Agreement as the "Employment Term."

          (b)  Duties.  As the President and Chief Executive Officer, the
               ------
Employee shall perform such duties, consistent with the Employee's job title, as
may be prescribed from time to time by the Board of Directors of the Company
(the "Board") and shall perform such duties as are described in the Company's
Bylaws.

          (c)  Chairman.  Employee has been elected a director of the Company
               --------
and serves as the Chairman of the Board. If the Employee hereafter ceases for
any reason to be the President and Chief Executive Officer of the Company, the
Employee will, if requested by the Company, resign as the Chairman of the Board
and as a director of the Company.

     2.   Term of Agreement.
          -----------------

     Subject to Section 7A hereof, the term of this Agreement shall commence on
the Agreement Date and shall continue through the last day of the Employment
Term, subject to any earlier termination of Employee's status as an employee
pursuant to the terms of this Agreement. Unless otherwise agreed by the parties,
Employee shall retire from his position as President, Chief Executive Officer
and Chairman of the Board on March 28, 2002. Subject to Section 7A hereof,
following the term of this Agreement, each party shall have the right to enforce
all rights, and shall be bound by all obligations, of such party that are
continuing rights and obligations under the terms of this Agreement.

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     3.   Devotion to Responsibilities.
          ----------------------------

     During the Employment Term, the Employee will devote all of his time and
attention to the business of the Company, and he will not engage in or be
employed by any other business activity or business, whether or not such
business activity or business is for gain, profit or other pecuniary advantage;
provided, however, that nothing herein contained shall prohibit the Employee
from (i) serving as a member of the Board of Directors, Board of Trustees or the
like of any for profit or non-profit entity, or performing services of any type
for any civic or community entity, whether or not the Employee receives
compensation therefor, (ii) investing his assets in such form or manner as will
require no more than nominal services on the part of the Employee in the
operation of the business of the entity in which such investment is made, or
(iii) serving in various capacities with, and attending meetings of, industry or
trade groups and associations, including without limitation the industry or
trade groups and associations with which the Employee is currently involved, as
long as the Employee's engaging in any activities permitted by virtue of clauses
(i), (ii) and (iii) above does not materially and unreasonably interfere with
the ability of the Employee to perform the services and discharge the
responsibilities required of him under this Agreement. Notwithstanding clause
(ii) above, during the Employment Term, the Employee may not beneficially own
more than 2% of the outstanding shares of any class of equity security of a
business organization required to file periodic reports with the Securities and
Exchange Commission under the Securities Exchange Act of 1934 (the "Exchange
Act") and may not beneficially own more than 5% of the outstanding shares of any
class of equity security of a business organization that competes with the
Company. For purposes of this paragraph, "beneficially own" shall have the same
meaning ascribed to that term in Rule 13d-3 under the Exchange Act.

     4.   Compensation and Benefits.  The Company will provide the Employee with
          -------------------------
the compensation and benefits described below:

          (a)  Salary.  An annual salary during the Employment Term of $700,000
               ------
("Annual Base Compensation"), payable to the Employee in equal semi-monthly
installments.

          (b)  Bonus.  An annual incentive bonus, payable, if at all, only with
               -----
respect to services provided by the Employee during the Employment Term.  The
annual incentive bonus will be determined, accrued and paid in accordance with
the terms of the Company's Executive Officer Annual Incentive Plan (the
"Incentive Plan") that covers certain executive officers designated by the
Compensation Committee of the Board (the "Committee") or any incentive or bonus
compensation plan that is a successor or substitute therefor.  The parties
acknowledge and agree that this Section 4(b) imposes no obligation on the
Company to award a bonus to the Employee.  A copy of the Incentive Plan in
effect for fiscal year 2001 is attached as Appendix A.

          (c)  Stock Options.  The outstanding options to purchase shares of the
               -------------
common stock of the Company held by Employee have the vesting terms and post-
retirement exercise periods described on Appendix B hereto.  Options granted to
Employee by the Company in the future during the Employment Term shall vest upon
retirement at age 65 or later and shall have a post-retirement exercise period
of at least five years.

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          (d)  Compensating Retirement Benefit.  In addition to any benefits
               -------------------------------
payable to Employee after his retirement by virtue of his participation in the
Tidewater defined benefit pension plan and Supplemental Executive Retirement
Plan, the Company shall, from and after the date of the Employee's normal
retirement on or after age 65 (the "Retirement Date"), pay to the Employee, from
time to time, such additional amounts as are necessary to make the Employee's
total retirement benefits payable after the Retirement Date (including
retirement benefits provided by Employee's prior employer and benefits paid
prior to the Retirement Date under the Tidewater defined benefit plan and
Supplemental Executive Retirement Plan) not less in amount than the retirement
benefits to which the Employee would have been entitled under the terms of any
qualified and non-qualified defined benefit pension plans of his immediate prior
employer, assuming that Employee's employment by his immediate prior employer
had terminated on the Retirement Date. In addition to any benefits payable to
Employee by virtue of his participation in the Tidewater defined benefit pension
plan and Supplemental Executive Retirement Plan, in the event his employment
with the Company is terminated for any reason (including his death) prior to age
65, the Company shall pay to the Employee from time to time, such additional
amounts as are necessary to make the Employee's total retirement benefits
payable after such termination of employment (including retirement benefits
provided by Employee's prior employer and benefits paid prior to the date of
termination of employment under the Tidewater defined benefit plan and
Supplemental Executive Retirement Plan) not less than the amount that the
Employee would have been entitled to receive under the defined benefit pension
plans of his immediate prior employer, assuming that Employee's employment by
his immediate prior employer had terminated on the same date his employment with
the Company is terminated. In making any benefit calculation contemplated
hereby, it shall be assumed that the Employee's compensation for purposes of
such plans was, for periods prior to the date his employment with the Company
commenced (the "Commencement Date"), his covered compensation with such prior
employer and, for periods after the Commencement Date, his compensation under
this Agreement or a predecessor agreement between the Company and the Employee.
This compensating retirement benefit will be paid in the same manner as payments
are made under the Company's Supplemental Executive Retirement Plan and will be
based on calculations using the same actuarial assumptions used in the Company's
defined benefit plan. The Employee has provided the Company with copies of all
documents related to retirement compensation available to the Employee from the
prior employer, which documents are attached hereto as Appendix C. Attached as
Appendix D is the calculation of the additional amount that Employee shall be
paid following retirement on or after the Retirement Date in order that his
retirement benefits will be no less than the retirement benefits that he would
have been entitled to receive following retirement on the Retirement Date under
the terms of the qualified and non-qualified defined benefit pension plans of
his immediate prior employer, which amount is subject to adjustment if and to
the extent that the assumptions relied upon for such calculation (as stated in
Appendix D) differ from the facts at the time of Employee's retirement.

          (e)  Indemnification.  Under its Bylaws, the Company provides, as of
               ---------------
the Agreement Date, certain indemnification rights to its officers and directors
that will be applicable to the Employee with respect to his acts and omissions
in his capacity as an officer and director of the Company.  The Company agrees
to provide indemnification rights to the Employee identical to

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those provided for in its Bylaws as in existence on the Agreement Date as to all
suits or proceedings to which the Employee is or is threatened to be made a
party that arise out of or are connected to his services during the Employment
Term, without regard to whether such actions, suits or proceedings are made,
asserted or arise during or after the Employment Term.

          (f)  Other Benefits.  During the Employment Term, the Employee shall
               --------------
be entitled to all benefits and perquisites provided to senior executive
employees of the Company, including but not limited to the benefits referred to
in Appendix E hereof.

     5.   Expenses.  The Employee will be reimbursed for out-of-pocket expenses
          --------
incurred from time to time on behalf of the Company or any subsidiary in the
performance of his duties under this Agreement, upon the presentation of such
supporting invoices, documents and forms as the Company reasonably requests.

     6.   Termination of Employment.
          -------------------------

          (a)  Death or Disability.  The Employee's status as an employee will
               -------------------
terminate immediately and automatically upon the Employee's death during the
Employment Term.  If (i) the Employee is rendered incapable because of physical
or mental illness of satisfactorily discharging his duties and responsibilities
under this Agreement for a period of 60 consecutive days and (ii) a duly
qualified physician chosen by the Company and acceptable to the Employee or his
legal representatives so certifies in writing, the Board shall have the power to
determine that the Employee has become disabled.  If the Board makes such a
determination, the Company shall have the continuing right and option, during
the period that such disability continues, and by notice given in the manner
provided in Section 15, to terminate the status of Employee as an employee.  Any
such termination shall become effective thirty days after such notice of
termination is given (the "Disability Effective Date"), unless within such
thirty day period, the Employee becomes capable of rendering services of the
character contemplated hereby (and a physician chosen by the Company and
acceptable to the Employee or his legal representatives so certifies in writing)
and the Employee in fact resumes such services.  The Employee's death or the
Employee's incapacity due to physical or mental illness to discharge the
responsibilities assigned by this Agreement shall not constitute a breach of
this Agreement by the Employee.

          (b)  Cause.  The Company may terminate the Employee's status as an
               -----
employee for Cause.  As used herein, termination by the Company of the
Employee's status as an employee for "Cause" shall mean termination as a result
of (i) the willful and continuing failure by the Employee to perform the
services contemplated by this Agreement (other than any such failure resulting
from the Employee's disability of the type specified in Section 6(a)), (ii) the
Employee's breach of or failure to comply with the covenants set forth in
Sections 8, 9 or 11 of this Agreement, or (iii) the willful engaging by the
Employee in gross misconduct injurious to the Company; provided that, no act, or
failure to act, on the Employee's part shall be considered "willful" for
purposes of this Agreement unless done, or omitted to be done, without a
reasonable belief that such action or omission was in, or not opposed to, the
best interests of the Company.  Any act, or failure to act, by the Employee that
is based upon authority given pursuant to a resolution duly adopted by

                                      -4-
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the Board or based upon the advice of counsel for the Company shall be presumed
to be done, or omitted to be done, by the Employee in good faith and in the best
interests of the Company.

          (c)  Good Reason.  The Employee may terminate his status as an
               -----------
employee for Good Reason. The termination by the Employee of his status as an
employee for Good Reason shall be deemed to be a justifiable termination and
shall excuse the Employee from the obligation to render services under or
relating to this Agreement. As used herein, the term "Good Reason" shall mean:

               (i)   The occurrence of any of the following during the
Employment Term:

                     (A) the assignment by the Board to the Employee of any
duties or responsibilities which are inconsistent with the Employee's status,
title and position as President and Chief Executive Officer of the Company;

                     (B) any removal of the Employee from, or any failure to
reappoint or reelect the Employee to, the position of President and Chief
Executive Officer of the Company, except in connection with a termination by the
Company of the Employee's employment for Cause or on account of disability or
death of the Employee, or the termination by the Employee of his employment
other than for Good Reason;

                     (C) the Company's requiring the Employee to be based
anywhere other than in New Orleans, Louisiana, except for required travel in the
ordinary course of the Company's business;

               (ii)  a reduction in the Employee's annual salary or a failure by
the Company to pay to the Employee any installment of the annual salary or to
pay any other amounts required to be paid under this Agreement, which failure
continues for a period of ten days after written notice thereof is given by the
Employee to the Company;

               (iii) the failure by the Company to obtain the assumption of its
obligations under this Agreement by any successor or assign as contemplated in
Paragraph 13 of the Agreement;

               (iv)  any purported termination by the Company of the Employee's
status as an employee which is not effected pursuant to a Notice of Termination
satisfying the requirements of Paragraph 6(d) hereof, or which is not justified
as a termination based on Cause; or

               (v)   any breach of this Agreement by the Company.

          (d)  Notice of Termination.  Any purported notice of termination of
               ---------------------
the Employee's status as an employee must be communicated in a writing delivered
to the other party as provided in Paragraph 15 hereof (a notice of termination
complying with this sentence is referred to in this Agreement as a "Notice of
Termination"). Any such Notice of Termination that purports to terminate
Employee's employment for Cause or for Good Reason shall specify the provision
or

                                      -5-
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provisions of this Agreement relied upon by the party giving such notice and
shall set forth in reasonable detail the facts and circumstances claimed by such
party to provide a basis for termination of the Employee's employment under the
provision(s) so indicated.

          (e)  Date of Termination.  "Date of Termination" means (i) if
               -------------------
Employee's employment is terminated by the Company for Cause, or by Employee for
Good Reason, the date of delivery of the Notice of Termination or any later date
specified therein, as the case may be, (ii) if the Employee's employment is
terminated by the Company other than for Cause or disability, the Date of
Termination shall be the date on which the Company notifies the Employee of such
termination and (iii) if Employee's employment is terminated by reason of his
death or disability, the Date of Termination shall be the date of death of
Employee or the Disability Effective Date, as the case may be.

     7.   Obligations of the Company Upon Termination.
          -------------------------------------------

          (a)  Good Reason, Other than for Cause, Death or Disability.  If (i)
               ------------------------------------------------------
the Company terminates the Employee's status as an employee other than for
Cause, death or disability, or (ii) the Employee shall terminate his employment
for Good Reason, then the Company shall pay to the Employee in a lump sum in
cash within 30 days after the Date of Termination the aggregate of the following
amounts:

                    (A)  the sum of (1) the amount of the Employee's Annual Base
Compensation earned through the Date of Termination, to the extent not
theretofore paid and (2) any compensation previously deferred by the Employee
(together with any accrued interest on earnings thereon) and any accrued
vacation pay, in each case to the extent not previously paid (the sum of the
amounts described in clauses (1) and (2) being hereinafter referred to as the
"Accrued Obligations").

                    (B)  the aggregate amount of the Employee's Annual Base
Compensation for the period beginning the day of the Date of Termination and
continuing through the last day of the Employment Term (such amount being
referred to herein as the "Non-Accrued Compensation").

                    (C)  to the extent not theretofore paid or provided, the
Company shall timely pay or provide to the Employee any other amounts required
to be paid or provided or which the Employee is eligible to receive under any
plan, program, policy or practice of the Company (such other amounts being
referred to herein as the "Other Benefits").

          (b)  Death.  If the Employee's status as an employee is terminated by
               -----
reason of the Employee's death, this Agreement shall terminate without further
obligations to the Employee's legal representatives under this Agreement, other
than for payment of (i) Accrued Obligations, (ii) 50% of the Non-Accrued
Compensation (the "Death Cash Payment") and (iii) the timely payment or
provision of Other Benefits.  The sum of the Accrued Obligations and the Death
Cash Payment shall be paid to the Employee's estate or beneficiary, as
applicable, in a lump sum in cash within 30 days of the Date of Termination.
With respect to the provision of Other Benefits, the term Other

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Benefits as used in this Section 7(b) shall include, without limitation, and the
Employee's estate and/or beneficiaries shall be entitled to receive, benefits at
least equal to the most favorable benefits provided by the Company to the
estates and beneficiaries of its senior executive officers under such plans,
programs, practices and policies relating to death benefits, if any, as in
effect on the date of Employee's death.

          (c)  Disability.  If Employee's status as an employee is terminated by
               ----------
reason of Employee's disability, this Agreement will terminate without further
obligation to the Employee, other than the payment of (i) Accrued Obligations,
(ii) 50% of the Non-Accrued Compensation (the "Disability Cash Payment") and
(iii) the timely payment or provision of Other Benefits.  The sum of Accrued
Obligations and the Disability Cash Payment will be paid to the Employee in a
lump sum in cash within 30 days of the Date of Termination.  With respect to the
provision of Other Benefits, the term Other Benefits as used in this Section
7(c) shall include, and the Employee will be entitled after the Disability
Effective Date to receive, disability and other benefits at least equal to the
most favorable of those generally provided by the Company to disabled executive
officers and their families in accordance with such plans, programs, practices
and policies related to disability that are in effect on the Disability
Effective Date.

          (d)  Cause, Other than for Good Reason.  If the Employee's status as
               ---------------------------------
an employee shall be terminated for Cause by Employer, or voluntarily terminated
by Employee other than for Good Reason, this Agreement shall terminate without
further obligation to the Employee other than for (i) Accrued Obligations, which
shall be paid in a lump sum in cash within 30 days of the Date of Termination,
and (ii) to the extent not theretofore paid or provided, the Company shall
timely pay or provide to the Employee his accrued, vested benefits under any
benefit plan or program of the Company.

     7A.  Obligations of the Company and the Employee in the Event of a Change
          --------------------------------------------------------------------
          of Control
          ----------

          (a)  Upon and following a Change of Control of the Company (as defined
in Section 7A(b) hereof), the rights and obligations of the Employee and the
Company shall not be governed by this Agreement, but shall be as provided in the
Change of Control Agreement between the Employee and the Company dated effective
October 1, 1999 and any amendments thereto or any subsequent change of control
agreement between the Employee and the Company (including any rights or
obligations in this Agreement which are specifically incorporated by reference
therein).  Upon the occurrence of a Change of Control, the term of the Agreement
shall end, and the provisions of the Agreement (including, without limitation,
the Employee's covenant not to compete) shall be null and void, and of no
further force and effect, except that compensation, benefit and indemnification
obligations accrued by the Company with respect to the Employee prior to the
Change of Control and during the term of the Agreement shall remain valid and
enforceable.

          (b)  Change of Control.  As used in this Section 7A, "Change of
Control" shall mean:

                                      -7-
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               (i)   the acquisition by any "Person" (as defined in Section
7A(c) hereof) of "Beneficial Ownership" (as defined in Section 7A(c) hereof) of
30% or more of the outstanding Shares of the Company's Common Stock, $0.10 par
value per share (the "Common Stock") or 30% or more of the combined voting power
of the Company's then outstanding securities; provided, however, that for
purposes of this subsection 7A(b)(i), the following shall not constitute a
Change of Control:

                     (A) any acquisition (other than a "Business Combination"
(as defined in Section 7A(b)(iii) hereof) which constitutes a Change of Control
under Section 7A(b)(iii) hereof) of Common Stock directly from the Company,

                     (B) any acquisition of Common Stock by the Company or its
subsidiaries,

                     (C) any acquisition of Common Stock by any employee benefit
plan (or related trust) sponsored or maintained by the Company or any
corporation controlled by the Company, or

                     (D) any acquisition of Common Stock by any corporation
pursuant to a Business Combination which does not constitute a Change of Control
under Section 7A(b)(iii) hereof; or

               (ii)  individuals who, as of the effective date of this amendment
to the Agreement, constitute the Board (the "Incumbent Board") cease for any
reason to constitute at least a majority of the Board; provided, however, that
any individual becoming a director subsequent to the effective date of this
amendment whose election, or nomination for election by the Company's
shareholders, was approved by a vote of at least a majority of the directors
then comprising the Incumbent Board shall be considered a member of the
Incumbent Board, unless such individual's initial assumption of office occurs as
a result of an actual or threatened election contest with respect to the
election or removal of directors or other actual or threatened solicitation of
proxies or consents by or on behalf of a Person other than the Incumbent Board;
or

               (iii) consummation of a reorganization, merger or consolidation
(including a merger or consolidation of the Company or any direct or indirect
subsidiary of the Company), or sale or other disposition of all or substantially
all of the assets of the Company (a "Business Combination"), in each case,
unless, immediately following such Business Combination,

                     (A) the individuals and entities who were the Beneficial
Owners of the Company's outstanding Common Stock and the Company's voting
securities entitled to vote generally in the election of directors immediately
prior to such Business Combination have direct or indirect Beneficial Ownership,
respectively, of more than 50% of the then outstanding shares of common stock,
and more than 50% of the combined voting power of the then outstanding voting
securities entitled to vote generally in the election of directors, of the Post-
Transaction Corporation (as defined in Section 7A(c) hereof), and

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                     (B) except to the extent that such ownership existed prior
to the Business Combination, no Person (excluding the Post-Transaction
Corporation and any employee benefit plan or related trust of either the
Company, the Post-Transaction Corporation or any subsidiary of either
corporation) Beneficially Owns, directly or indirectly, 30% or more of the then
outstanding shares of common stock of the corporation resulting from such
Business Combination or 30% or more of the combined voting power of the then
outstanding voting securities of such corporation, and

                     (C) at least a majority of the members of the board of
directors of the Post-Transaction Corporation were members of the Incumbent
Board at the time of the execution of the initial agreement, or of the action of
the Board, providing for such Business Combination; or

               (iv)  approval by the shareholders of the Company of a complete
liquidation or dissolution of the Company.

          (c)  Other Definitions.  As used in Section 7A(b) hereof, the
following words or terms shall have the meanings indicated:

               (i)   Affiliate:  "Affiliate" (and variants thereof) shall mean a
Person that controls, or is controlled by, or is under common control with,
another specified Person, either directly or indirectly.

               (ii)  Beneficial Owner:  "Beneficial Owner" (and variants
thereof), with respect to a security, shall mean a Person who, directly or
indirectly (through any contract, understanding, relationship or otherwise), has
or shares (i) the power to vote, or direct the voting of, the security, and/or
(ii) the power to dispose of, or to direct the disposition of, the security.

               (iii) Person: "Person" shall mean a natural person or company,
and shall also mean the group or syndicate created when two or more Persons act
as a syndicate or other group (including, without limitation, a partnership or
limited partnership) for the purpose of acquiring, holding, or disposing of a
security, except that "Person" shall not include an underwriter temporarily
holding a security pursuant to an offering of the security.

               (iv)  Post-Transaction Corporation:  Unless a Change of Control
includes a Business Combination (as defined in Section 7A(b)(iii) hereof),
"Post-Transaction Corporation" shall mean the Company after the Change of
Control.  If a Change of Control includes a Business Combination, "Post-
Transaction Corporation" shall mean the corporation resulting from the Business
Combination unless, as a result of such Business Combination, an ultimate parent
corporation controls the Company or all or substantially all of the Company's
assets either directly or indirectly, in which case, "Post-Transaction
Corporation" shall mean such ultimate parent corporation."

     8.   Trade Secrets, Etc.  The Employee shall hold in a fiduciary capacity
          -------------------
for the benefit of the Company all secret or confidential information, knowledge
or data relating to the Company or any of its subsidiaries or corporate
affiliates and their respective businesses and operations, which

                                      -9-
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shall have been obtained by the Employee during the Employee's employment
(whether prior to or after the Commencement Date) and which shall not have
become public knowledge (other than by acts of the Employee or any of his
representatives in violation of this Agreement). At the end of the Employment
Term, the Employee agrees (i) not, without the prior written consent of the
Company or as may be otherwise required by law or legal process, to communicate
or divulge any such information, knowledge or data to any party other than the
Company and (ii) to deliver promptly to the Company any confidential
information, knowledge or data in his possession, whether produced by the
Company or any of its subsidiaries and corporate affiliates or by the Employee,
that relates to the business of the Company or any of its subsidiaries and joint
ventures or any past, current or prospective activity of the Company or any of
its subsidiaries and joint ventures. The Employee shall be permitted to retain
copies of such data as are necessary in order to enable the Employee to assert
any rights under this Agreement, provided that such data shall be used solely
for such purpose.

     9.   Customer Lists.  The Employee recognizes and acknowledges that any
          --------------
written list or lists of the customers of the Company or any of its subsidiaries
and joint ventures ("customer lists"), as such customer lists may exist from
time to time, are valuable, special and unique assets of the Company.  The
Employee agrees that he will not use for his own personal benefit or disclose
such customer lists to any person, firm, corporation, association or other
entity for any reason or purpose whatsoever.  Personal and social contacts with
past, present or future customers of the Company shall not be prohibited hereby.

     10.  Limited Covenant Not to Compete.  For a period of two years commencing
          -------------------------------
with the expiration of the term of this Agreement, the Employee will not,
directly or indirectly, own, manage, operate, control, be employed by,
participate in, or be connected in any manner with the ownership, management,
operation or control of any company or other business enterprise engaged in the
business of providing vessel services for the offshore oil and gas industry,
within any parish of the State of Louisiana (as set forth in Appendix F), or any
other jurisdiction (whether within or outside the United States), in which the
Company or any of its subsidiaries or joint ventures carries on the business of
vessel services for the offshore oil and gas industry, so long as the Company or
any of its subsidiaries or joint ventures carries on a like line of business
therein; provided, however, that nothing contained herein shall (a) prohibit the
Employee from making investments in any publicly held company which do not
exceed in the aggregate two percent of the equity interest of such company or
(b) prohibit the Employee from continuing to hold any of the director or officer
positions held by him as of the date of this Agreement that are disclosed on
Appendix G hereto.

     11.  Certain Proprietary Rights.  The Employee agrees to and hereby does
          --------------------------
assign to the Company all his right, title and interest in and to all
inventions, business plans, work models or procedures, whether or not
patentable, which are made or conceived solely or jointly by him:

          (a)  At any time during the term of his employment by the Company, or

          (b)  With the use of time or materials of the Company.  The Employee
agrees to communicate to the Company or its representatives all facts known to
him concerning such matters, to sign all necessary instruments, make all
necessary oaths and generally, at the Company's expense,

                                      -10-
<PAGE>

to do everything reasonably practicable (without expense to the Employee) to aid
the Company in obtaining and enforcing proper legal protection for all such
matters in all countries and in vesting title to such matters in the Company. At
the Company's request (during or after the term of this Agreement) and expense,
the Employee will promptly execute a specific assignment of title to the
Company, and perform any other acts reasonably necessary to implement the
foregoing assignment.

     12.  Injunctive Relief.  In the event of a breach or threatened breach by
          -----------------
the Employee of the provisions of Sections 8, 9, 10 or 11 of this Agreement
during or after the term of this Agreement, the Company shall be entitled to
injunctive relief restraining the Employee from violation of such paragraph.
Nothing herein shall be construed as prohibiting the Company from pursuing any
other remedy at law or in equity it may have in the event of breach or
threatened breach of this Agreement by the Employee.

     13.  Binding Effect.
          --------------

          (a)  This Agreement shall be binding upon and inure to the benefit of
the Company and any of its successors or assigns.

          (b)  This Agreement is personal to the Employee and shall not be
assignable by the Employee without the consent of the Company (there being no
obligation to give such consent) other than such rights or benefits as are
transferred by will or the laws of descent and distribution.

          (c)  The Company will require any successor or assign (whether direct
or indirect, by purchase, merger, consolidation or otherwise) to all or
substantially all of the assets or businesses of the Company (i) to assume
unconditionally and expressly this Agreement and (ii) to agree to perform all of
the obligations under this Agreement in the same manner and to the same extent
as would have been required of the Company had no assignment or succession
occurred, such assumption to be set forth in a writing reasonably satisfactory
to the Employee.  In the event of any such assignment or succession, the term
"Company" as used in this Agreement shall refer also to such successor or
assign.

     14.  Notices.  Any notice or other communication required under this
          -------
Agreement shall be in writing, shall be deemed to have been given and received
when delivered in person, or, if mailed, shall be deemed to have been given when
deposited in the United States mail, first class, registered or certified,
return receipt requested, with proper postage prepaid, and shall be deemed to
have been received on the third business day thereafter, and shall be addressed
as follows:

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<PAGE>

     If to the Company, addressed to:

     Tidewater Inc.
     Pan American Life Center
     601 Poydras Street, Suite 1900
     New Orleans, Louisiana  70130
     Attn:  Cliffe F. Laborde
            Senior Vice President and Secretary

     If to the Employee, addressed to:

     William C. O'Malley
     Pan American Life Center
     601 Poydras Street, Suite 1900
     New Orleans, Louisiana  70130

or such other address as to which any party hereto may have notified the other
in writing.

     15.  Governing Law.  This Agreement shall be governed by and interpreted in
          -------------
accordance with the laws of the State of Louisiana.

     16.  Entire Agreement.  This Agreement, including Appendices A through G,
          ----------------
inclusive, all of which are herein incorporated by reference and made a part
hereof, and the documents referred to herein, contain or refer to the entire
arrangement or understanding between the Employee and the Company relating to
the employment of the Employee by the Company.  No provision of the Agreement,
including the Appendices, may be modified or amended except by an instrument in
writing signed by or for both parties hereto.

     17.  Severability.  If any term or provision of this Agreement, or the
          ------------
application thereof to any person or circumstance, shall at any time or to any
extent be invalid or unenforceable, the remainder of this Agreement, or the
application of such term or provision to persons or circumstances other than
those as to which it is held invalid or unenforceable, shall not be affected
thereby and each term and provision of this Agreement shall be valid and
enforced to the fullest extent permitted by law.

     18.  Waiver of Breach.  The waiver by either party of a breach of any
          ----------------
provision of this Agreement shall not operate or be construed as a waiver of any
subsequent breach thereof.

     19.  Remedies Not Exclusive.  No remedy specified herein shall be deemed to
          ----------------------
be such party's exclusive remedy, and accordingly, in addition to all of the
rights and remedies provided for in this Agreement, the parties shall have all
other rights and remedies provided to them by applicable law, rule or
regulation.

                                      -12-
<PAGE>

     20.  Beneficiaries.  Whenever this Agreement provides for any payment to be
          -------------
made to the Employee or his estate, such payment may be made instead to such
beneficiary or beneficiaries as the Employee may have designated in writing and
filed with the Company.  The Employee shall have the right to revoke any such
designation from time to time and to redesignate any beneficiary or
beneficiaries by written notice to the Company.

     21.  Company's Reservation of Rights.  Employee acknowledges and
          -------------------------------
understands that the Employee serves at the pleasure of the Board and that the
Company has the right at any time to terminate Employee's status as an employee
of the Company, or to change or diminish his status as the Chief Executive
Officer during the Employment Term, subject to the rights of the Employee to
claim the benefits conferred by Section 7(a) hereof if such action constitutes a
termination by the Company without Cause or a termination by the Employee for
Good Reason.

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

                                        TIDEWATER INC.



Date of Execution: Oct. 12, 2000        By: /s/ Robert H. Boh
                  -----------------         ------------------------------------
                                            Name:  Robert H. Boh
                                            Title: Director and Chairman of the
                                                   Compensation Committee of the
                                                   Board of Directors

                                        EMPLOYEE:


Date of Execution: Oct. 16, 2000        /s/ William C. O'Malley
                   ----------------    -----------------------------------------
                              Name:    William C. O'Malley

                                      -13-