Exhibit 10.18

FIRST AMENDMENT TO NOTE PURCHASE AGREEMENTS

THIS FIRST AMENDMENT, dated as of December 14th, 2001, to the separate Note Purchase Agreements, each dated as of April 30, 2001, is by and among
Flow International Corporation, a Washington corporation (the"Company"), John Hancock Life Insurance Company, John Hancock Variable Life Insurance
Company, Signature 4 Limited and Signature 5 L.P. (collectively, the"Noteholders"). Capitalized terms used herein without definition shall have the
meanings set forth in the Note Purchase Agreements referred to below (including as amended hereby).

R E C I T A L S:

A.The Company and the Noteholders have heretofore entered into the separate Note Purchase Agreements, each dated as of
April 30, 2001 (the"Note Purchase Agreements"), under and pursuant to which there are outstanding (a) the Company's 13% Senior
Subordinated Notes, due April 30, 2008, in the aggregate principal amount of $35,000,000 (the"Notes") and (b) certain Warrants to
purchase common stock of the Company (the"Warrants").

B.The Company and the Noteholders now desire to amend the Note Purchase Agreements in the respects, but only in the
respects, hereinafter set forth.

NOW,
THEREFORE, the Company and the Noteholders, for good and valuable consideration the receipt and sufficiency of which is hereby acknowledged, do hereby agree as follows:

SECTION 1.    AMENDMENTS.

Section 1.1.    Quarterly Financial Statements.Subclauses (i) and (ii) of
Section 7.1(a) of the Note Purchase Agreements are amended by deleting such subclauses in their entirety and inserting in lieu thereof the following:



Section 1.2.    Annual Financial Statements.Subclauses (i) and (ii) of Section 7.1(b)
of the Note Purchase Agreements are amended by deleting such subclauses in their entirety and inserting in lieu thereof the following:



Section 1.3.    Funded Debt Ratio.The first sentence of Section 9.7 of the Note Purchase Agreements
is amended by deleting such sentence in its entirety and inserting in lieu thereof the following:



---



Section 1.4.    Senior Funded Debt Ratio.The first sentence of Section 9.9 of the Note Purchase
Agreements is amended by deleting such sentence in its entirety and inserting in lieu thereof the following:



SECTION 2.    CONSENT.

Section 2.1.Notwithstanding the provisions of Section 10.10(a) of the Note Purchase
Agreements to the contrary, the Noteholders hereby agree that, so long as no Default or Event of Default has occurred and is continuing under the Note Purchase Agreements, the Company shall be
permitted to prepay (a) up to 50% of the aggregate principal amount of the senior notes outstanding under the Senior Private Placement Agreement (which the parties hereto agree are outstanding
in the aggregate principal amount of $8,571,286 on the date of this First Amendment) on or prior to January 31, 2002 and (b) the remaining balance of such senior notes on or prior to
October 31, 2002, all on the terms set forth in the Sixth Amendment to the Senior Private Placement Agreement attached hereto as Exhibit D,as in effect on the date of this First Amendment.

SECTION 3.    REPRESENTATIONS AND WARRANTIES OF THE COMPANY.

To induce the Noteholders to execute and deliver this First Amendment, the Company represents and warrants to the Noteholders (which representations and
warranties shall survive the execution and delivery of this First Amendment) that:



2

---



SECTION 4.    CONDITIONS TO EFFECTIVENESS OF THIS FIRST AMENDMENT.

This First Amendment shall not become effective until, and shall become effective when:



Upon
satisfaction of all of the foregoing, this First Amendment shall become effective.

SECTION 5.    MISCELLANEOUS.

This First Amendment shall be construed in connection with and as part of the Note Purchase Agreements, and except as modified and expressly amended by this
amendment, all terms, conditions and covenants contained in the Note Purchase Agreements, the Notes and the Warrants are hereby ratified and confirmed and shall be and remain in full force and effect.
The obligations of the Company under the Note Purchase Agreements, the Notes and the Warrants shall not be released, discharged or in any way affected by (a) any exercise or nonexercise of any
right, remedy, power or privilege under or in respect of the Note Purchase Agreements, the Notes or the Warrants or applicable law, including, without limitation, any waiver, consent, extension,
indulgence or other action or inaction in respect thereof; or (b) any other act or thing or omission or delay to do any other act or thing which could operate as or be deemed to be a discharge
of the Company as a matter of law, other
than payment in full of all obligations under the Note Purchase Agreements and the Notes and performance under the Warrants.

Any
and all notices, requests, certificates and other instruments executed and delivered after the execution and delivery of this amendment may refer to the Note Purchase Agreements
without making specific reference to this amendment, but nevertheless all such references shall be deemed to include this amendment unless the context otherwise requires.

3

---

This
First Amendment may be executed in any number of counterparts, each executed counterpart constituting an original, but all together only one agreement.

This First Amendment shall be construed and enforced in accordance with, and the rights of the parties shall be governed by, the law of the State of Washington,
excluding choice-of-law principles of the law of such State that would require the application of the laws of a jurisdiction other than such State.

Oral agreements or oral commitments to loan money, extend credit, or to forbear from enforcing repayment of a debt are not enforceable under Washington
Law.

4

---

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

| |  | THE COMPANY:                  
| |  | ------------------------------
| |  | FLOW INTERNATIONAL CORPORATION
| |  | By                            
| |  | Its                           

5

---

| |  |                                              | 
| |  | -------------------------------------------- | 
| |  | THE NOTEHOLDERS:                            
| |  | JOHN HANCOCK LIFE INSURANCE COMPANY         
| |  | By                                           | 
| |  |                                              | 
| |  | Its                                          | 
| |  |                                              | 
| |  |                                              | 
| |  |                                              | 
| |  | JOHN HANCOCK VARIABLE LIFE INSURANCE COMPANY
| |  | By                                           | 
| |  |                                              | 
| |  | Its                                          | 
| |  |                                              | 
| |  |                                              | 
| |  |                                              | 

| |  | SIGNATURE 4 LIMITED                                         
| |  | ------------------------------------------------------------
| |  | By John Hancock Life Insurance Company, as Portfolio Adviser
| |  | By                                                          
| |  |                                                             
| |  | Its                                                         
| |  |                                                             
| |  |                                                             
| |  |                                                             
| |  | SIGNATURE 5 L.P.                                            
| |  | By John Hancock Life Insurance Company, as Portfolio Adviser
| |  | By                                                          
| |  |                                                             
| |  | Its                                                         
| |  |                                                             

6

---

ATTACHMENTS

Exhibit A        Amendment
Number Three to Senior Credit Agreement

Exhibit B        Amendment
Number Four to Senior Credit Agreement

Exhibit C        Fifth
Amendment to Senior Private Placement Agreement

Exhibit D        Sixth
Amendment to Senior Private Placement Agreement

7

---

QuickLinks