LOCK-UP AGREEMENT (LOUIS E. SCHAEFER, JR.) April 19, 2007

Exhibit C

LOCK-UP AGREEMENT (XXXXX X. XXXXXXXX, XX.)

April 19, 2007

XXXXXXX XXXXX & CO.
Xxxxxxx Lynch, Pierce, Xxxxxx & Xxxxx
          Incorporated,
X.X. Xxxxxx Securities Inc.
  as Representatives of the several
  Underwriters to be named in the
  within-mentioned Purchase Agreement
x/x Xxxxxxx Xxxxx & Xx.
     Xxxxxxx Lynch, Pierce, Xxxxxx & Xxxxx
          Incorporated
0 Xxxxx Xxxxxxxxx Xxxxxx
Xxx Xxxx, Xxx Xxxx 00000
X.X. Xxxxxx Securities Inc.
000 Xxxx Xxxxxx
Xxx Xxxx, Xxx Xxxx 00000

     Re:     Proposed Public Offering by Superior Offshore International, Inc.

Dear Sirs:

     The undersigned, a stockholder, officer or director of Superior Offshore International, Inc., a Delaware corporation (the “Company”), understands that Xxxxxxx Xxxxx & Co., Xxxxxxx Lynch, Pierce, Xxxxxx & Xxxxx Incorporated (“Xxxxxxx Xxxxx”) and X.X. Xxxxxx Securities Inc. (“X.X. Xxxxxx” and together with Xxxxxxx Xxxxx, the “Representatives”) and each of the other underwriters named in Schedule A to the Purchase Agreement propose to enter into a Purchase Agreement (the “Purchase Agreement”) with the Company and the Selling Stockholders named therein providing for the public offering of shares (the “Securities”) of the Company’s common stock, par value $0.01 per share (the “Common Stock”). In recognition of the benefit that such an offering will confer upon the undersigned as a stockholder, officer or director of the Company, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the undersigned agrees with each underwriter to be named in the Purchase Agreement that, during a period of 180 days from the date of the Purchase Agreement, the undersigned will not, without the prior written consent of the Representatives, directly or indirectly, (i) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant for the sale of, or otherwise dispose of or transfer any shares of the Company’s Common Stock or any securities convertible into or exchangeable or exercisable for Common Stock, whether now owned or hereafter acquired by the undersigned or with respect to which the undersigned has or hereafter acquires the power of disposition, or file, or cause to be filed, any registration statement under the Securities Act of 1933, as amended, with respect to any of the foregoing (collectively, the “Lock-Up Securities”) or (ii) enter into any swap or any other agreement or any transaction that

     transfers, in whole or in part, directly or indirectly, the economic consequence of ownership of the Lock-Up Securities, whether any such swap or transaction is to be settled by delivery of Common Stock or other securities, in cash or otherwise.

     Notwithstanding the foregoing, if:

     (1) during the last 17 days of the 180-day lock-up period, the Company issues an earnings release or material news or a material event relating to the Company occurs; or

     (2) prior to the expiration of the 180-day lock-up period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the 180-day lock-up period,

     the restrictions imposed by this lock-up agreement shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event, as applicable, unless the Representatives waive, in writing, such extension; provided, however, that in no event shall such restrictions extend past 214 days from the date of the Purchase Agreement.

     The undersigned hereby acknowledges and agrees that written notice of any extension of the 180-day lock-up period pursuant to the previous paragraph will be delivered by the Representatives to the Company (in accordance with Section 12 of the Purchase Agreement) and that any such notice properly delivered will be deemed to have been given to, and received by, the undersigned. The undersigned further agrees that, prior to engaging in any transaction or taking any other action that is subject to the terms of this lock-up agreement during the period from the date of this lock-up agreement to and including the 34^th day following the expiration of the initial 180-day lock-up period, it will give notice thereof to the Company and will not consummate such transaction or take any such action unless it has received written confirmation from the Company that the 180-day lock-up period (as may have been extended pursuant to the previous paragraph) has expired.

     The undersigned also agrees and consents to the entry of stop transfer instructions with the Company’s transfer agent and registrar against the transfer of the Lock-Up Securities except in compliance with the foregoing restrictions.

		Very truly yours,
		Signature:		/s/ Xxxxx X. Xxxxxxxx, Xx.
		Print Name:		Xxxxx X. Xxxxxxxx, Xx.

Signature Page to Lock Up Letter