<PAGE>

                                                                   EXHIBIT 10.13

Ocean Power Technologies, Inc.
1590 Reed Road
Pennington, NJ 08534

Re: Engagement of Thomas Meaney

                       CONSULTANT AGREEMENT ("AGREEMENT")
                          REVISION DATED AUGUST 1, 1999

Gentlemen:

     I am pleased to advise you that I, Thomas Meaney, ("Consultant") am
prepared to act as a consultant and an advisor to Ocean Power Technologies, Inc.
("OPT" or the "Company").

     1. Services. The services to be performed by the Consultant for and on
behalf of the Company hereunder are in relation to marketing effort directed
towards the U.S. Department of Defense and other U.S. Government Agenices for
potential funded projects for the development of the Company's technology, and
will include:

          (a) Outlining the range of technology tasks, proposed performance
goals, timetable and cost characteristics with OPT.

          (b) Identifying appropriate targets within the various agencies with
possible budgets via telephone enquiries and selected meetings, primarily in
Washington, DC., with existing contacts.

          (c) Reviewing reactions and budget details with OPT.

          (d) Reviewing presentation materials.

          (e) Arranging and, where appropriate, delivering these presentations

          (f) Delivering revised proposals and following up as required to
obtain contract(s).

          The Consultant shall devote its best efforts to performance and
discharge of its duties and responsibilities hereunder, and to the best interest
and welfare of the Company.

     2. Term. The Company agrees to engage the services of Consultant on a
monthly basis commencing August 1, 1999, and continuing through the termination
of this contract at the earliest of the following:

          (a) completion of the services set forth in 1 above to the
satisfaction of OPT, or any extensions thereto,

          (b) 30 days written notice from one party to the other, stating an
intent to terminate this Agreement,

<PAGE>

          (c) breach of this Agreement as provided here below.

     If either party breaches this Agreement and fails to correct the breach to
the reasonable satisfaction of the injured party within sixty (60) days
following a written notice from the injured party specifying the breach, this
Agreement shall terminate. In the event this Agreement is terminated, Consultant
will be entitled to receive and retain the portion of any compensation earned
pursuant to section 4 below which accrued but has not been paid through the
month in which such termination occurs.

     3. Cooperation. The Company will cooperate with Consultant in connection
with, and shall make available or cause to be made available to Consultant, such
documents and other information required for Consultant to perform its
obligations hereunder.

     4. Compensation. In consideration of the Consultant's services provided
hereunder, the Company agrees to compensate Consultant at the rate of $600.00
per day.

     The Company will reimburse the Consultant for all reasonable out-of-pocket
expenses incurred by Consultant in performance of its obligations hereunder. The
Consultant must have received prior written approval from the Company in order
to be reimbursed for any expense in excess of $100.00.

     5. Indemnification. The Company shall indemnify and hold harmless
Consultant from any claims, liabilities, losses, damages or expenses, including
legal fees, arising out of or in connection with, the services rendered by
Consultant pursuant to this Agreement, unless such claims, liabilities, losses,
damages or expenses, including legal fees, arise out of the gross negligence,
willful misconduct or any violation of law by the Consultant. The Consultant
shall indemnify and hold harmless the Company for any claims, liabilities,
losses, damages or expenses, including legal fees, arising out of the gross
negligence, willful misconduct or any violation of law by the Consultant.

     6. Independent Contractor. The Consultant shall be, and be deemed to be, an
independent contractor in the performance of the Consultant's duties hereunder.
The Consultant shall not, by reason of this Agreement or the performance of the
Consultant's duties hereunder, be or be deemed to be, an employee, agent,
partner or co-venturer of the Company; the Consultant shall have no power to
enter into any agreement on behalf of or otherwise bind the Company; and the
fees due hereunder shall be paid in gross without any deductions for federal
and/or state withholding taxes or any other applicable taxes. Except as
expressly set forth hereunder or as imposed by applicable law, the Consultant
shall not have, or be deemed to have, any fiduciary obligation or duties to the
Company. The Consultant shall be free to pursue, conduct and carry on for the
Consultant's own account (or for the account of others) such activities,
employment, ventures, businesses and other pursuits as the Consultant, in the
Consultant's sole, absolute and unfettered discretion, may elect.

     7. Confidentiality. Any financial information rendered by Consultant
pursuant to this Agreement may not be disclosed publicly in any manner without
the Company's prior written approval. All non-public information provided to
Consultant, or any of its affiliates, by the Company and all advice given by
Consultant to the Company will be treated as confidential


                                                                               2

<PAGE>

information, and Consultant agrees not to make use of such information and
advice other than for the performance of this Agreement, and shall not disclose
or release such information unless directed or permitted by such executive
officers of the Company, in writing.

     Consultant, by acceptance of this Agreement, expressly recognizes and
reaffirms the provisions and restraints imposed by the "Confidential Information
Inventions and Trade Secrets Agreement" attached hereto, and agrees that said
"Confidential Information, Inventions and Trade Secrets Agreement" constitutes
an express term of the retention of its services under this Agreement, and is an
independent covenant which shall remain in full force and effect notwithstanding
any termination of this Agreement or any provision thereof.

     8. Governing Law. This Agreement shall be governed by the laws of the State
of New Jersey, USA. Any dispute arising out of this Agreement shall be
adjudicated in the courts of the State of New Jersey or in the federal courts
sitting in the District of New Jersey and each of the Company and Consultant
hereby agrees that service of process by registered mail at Company's or
Consultant's address, shall be deemed adequate and lawful.


                                                                               3

<PAGE>

     Please confirm that the foregoing correctly and completely sets forth our
agreement by signing and returning the enclosed copy of this Agreement.

                                        Sincerely,

                                        CONSULTANT

                                              /s/ Thomas Meaney
                                        ----------------------------------------
                                        Thomas Meaney
                                                  9/22/99
                                        ----------------------------------------
                                        Date

                                        ###-##-####
                                        Social Security Number

                                        12 Fairhill Drive
                                        Address

                                        Chadds Ford, PA 19317
                                        Address


ACKNOWLEDGED AND AGREED TO
THIS 15 DAY OF SEPTEMBER, 1999.

OCEAN POWER TECHNOLOGIES, INC.


By: /s/ Charles F. Dunleavy
    ---------------------------------
Name: Charles F. Dunleavy
Title: Vice President, Finance


                                                                               4