Exhibit 10.4

Execution Version

AMENDMENT NO. 3 TO PROMISSORY NOTE

This Amendment No. 3 to Promissory Note (this “Amendment”), dated as of December
15, 2015, is entered into by and among Odyssey Marine Enterprises, Ltd., a
Bahamas company (the “Company”), whose address is Lyford Financial Centre,
Lyford Cay, P.O. Box N-7776, Nassau, Bahamas, Odyssey Marine Exploration, Inc.,
a Nevada corporation (the “Guarantor”), and Minera del Norte, S.A. de C.V. (the
“Lender”). Capitalized terms used in this Amendment but not otherwise defined
herein shall have the respective meanings ascribed to them in the Promissory
Note (as defined below).

R E C I T A L S:

WHEREAS, the Company, the Guarantor and the Lender entered into that certain
Promissory Note, dated as of March 11, 2015 (as amended by Amendment No. 1
thereto dated as of April 10, 2015, and Amendment No. 2 thereto dated as of
October 1, 2015, and in effect as of the date hereof, the “Promissory Note”);

WHEREAS, the Lender remains the Holder of the Promissory Note; and

WHEREAS, the Company, Guarantor and the Lender desire to amend the Promissory
Note as provided herein.

NOW THEREFORE, in consideration of the foregoing and the mutual covenants, and
agreements hereinafter set forth, and for other good and valuable consideration,
the receipt and sufficiency of which are hereby acknowledged, the parties
hereto, intending to be legally bound, hereby agree as follows:

1. Section 2(a). Section 2(a) of the Promissory Note is hereby amended by
deleting it in its entirety and inserting the following in lieu thereof:

“(a) Unless otherwise converted as provided herein, the Adjusted Principal
Balance shall be due and payable in full upon written demand by the Lender;
provided that the Lender agrees that it shall not demand payment of the Adjusted
Principal Balance earlier than the first to occur of: (i) 30 days after the date
on which (x) SEMARNAT makes a determination with respect to the current
application for the Manifestacion de Impacto Ambiental relating to the Don Diego
Project, which determination is other than an approval or (y) the Company or any
of its affiliates withdraws such application without the Lender’s prior written
consent; (ii) termination by Odyssey Marine Exploration, Inc. of the Stock
Purchase Agreement; (iii) the occurrence of an Event of Default; (iv) March 30,
2016; or (v) if and only if the Investor shall have terminated the Stock
Purchase Agreement pursuant to Section 8.1(d)(iii) thereof, March 30, 2016 (the
date of such demand being the “Maturity Date”).”

2. Release. In consideration of, among other things, Lender’s execution and
delivery of this Amendment, each of the Releasors hereby forever agrees and
covenants not to sue or prosecute against the Releasees and hereby forever
waives, releases and discharges each Releasee from,

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Execution Version

 

any and all Claims that such Releasor now has or hereafter may have, of
whatsoever nature and kind, whether known or unknown, whether arising at law or
in equity, against the Releasees, based in whole or in part on facts whether or
not now known, existing on or before December 14, 2015, that relate to, arise
out of or otherwise are in connection with this Amendment, the Promissory Note,
the Stock Purchase Agreement or any transactions contemplated hereby, thereby or
any acts or omissions in connection therewith or the negotiation thereof,
provided, however, that the foregoing shall not release the “Investor” and
“Guarantor” (as such terms are defined in the Stock Purchase Agreement) from the
express obligations of either under the Stock Purchase Agreement arising on or
after December 15, 2015. The provisions of this Section 5 shall survive the
repayment of the Promissory Note.

3. Representation and Warranties. The Company represents and warrants that the
representations and warranties set forth in Section 4 of the Promissory Note are
true and correct as of the date hereof, as if made as of the date hereof, except
to the extent such representations and warranties expressly relate to an earlier
date, in which case as of such earlier date. The Company and the Guarantor
hereby represent and warrant to the Lender that this Amendment (a) has been duly
authorized by the board of directors, or similar governing body, of the Company
and the Guarantor, including by the approval of a majority of the directors of
the Guarantor that are not affiliated with the Lender, (b) was duly executed by
the Company and the Guarantor, and (c) constitutes a legal, valid and binding
obligation of the Company and the Guarantor.

4. Full Force and Effect. Except as expressly modified by this Amendment, all of
the terms, covenants, agreements, conditions and other provisions of the
Promissory Note shall remain in full force and effect in accordance with their
respective terms. This Amendment shall not constitute an amendment or waiver of
any provision of the Promissory Note except as expressly set forth herein. Upon
the execution and delivery hereof, the Promissory Note shall thereupon be deemed
to be amended and supplemented as hereinabove set forth as fully and with the
same effect as if the amendments and supplements made hereby were originally set
forth in the Promissory Note, and this Amendment and the Promissory Note shall
henceforth be read, taken and construed as one and the same instrument, but such
amendments and supplements shall not operate so as to render invalid or improper
any action heretofore taken under the Promissory Note. As used in the Promissory
Note, the terms “this Note,” “herein,” “hereinafter,” “hereto,” and words of
similar import shall mean and refer to, from and after the date of this
Amendment, unless the context requires otherwise, the Promissory Note as amended
by this Amendment. For the avoidance of doubt, references to the phrases “the
date of this Note” or “the date hereof”, wherever used in the Promissory Note,
as amended by this Amendment, shall mean March 11, 2015. In the event of any
inconsistency between this Amendment and the Promissory Note with respect to the
matters set forth herein, this Amendment shall take precedence.

5. Governing Law. This Amendment, and all claims arising out of or relating to
it, shall be governed by and construed in accordance with the laws of the State
of New York, excluding that body of law relating to conflict of laws.

6. Counterparts. This Amendment may be executed in any number of counterparts,
each of which shall be enforceable against the parties actually executing such
counterparts, and all of which together shall constitute one instrument.

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Execution Version

 

IN WITNESS WHEREOF, the Company, the Guarantor and the Lender have caused this
Amendment to be executed as of the day and year as first written above.

 

ODYSSEY MARINE ENTERPRISES, LTD. By:  

/s/ Mark D. Gordon

Name:   Mark D. Gordon Title:   Vice President & Director Address:   ODYSSEY
MARINE EXPLORATION, INC. By:  

/s/ Mark D. Gordon

Name:   Mark D. Gordon Title:   President & CEO Address:  

 

ACCEPTED AND AGREED TO: MINERA DEL NORTE, S.A. DE C.V.

By:

 

/s/ Andres Gonzalez Saravia

Name:

 

Andres Gonzalez Saravia

Title:

 

Authorized Person

Address: