<PAGE>
 
                                                                   EXHIBIT 10.30

                              TENTH AMENDMENT TO
                              ------------------
                          LOAN AND SECURITY AGREEMENT
                          ----------------------------
                 AND AMENDMENT TO CERTAIN OTHER LOAN DOCUMENTS
                 ---------------------------------------------
                                        

          THIS TENTH AMENDMENT TO LOAN AND SECURITY AGREEMENT AND AMENDMENT TO
CERTAIN OTHER LOAN DOCUMENTS (the "Amendment") is made and entered into on this
12 day of November, 1998, to be effective (unless otherwise specified herein)
as of the date of execution of this Amendment, by and among FLEET CAPITAL
CORPORATION, a Rhode Island corporation, successor in interest by merger to
FLEET CAPITAL CORPORATION, a Connecticut corporation, formerly known as SHAWMUT
CAPITAL CORPORATION, successor in interest by assignment to BARCLAYS BUSINESS
CREDIT, INC. ("Lender"), LOWRANCE ELECTRONICS, INC., a Delaware corporation
("Lowrance"), LEI EXTRAS, INC., a Delaware corporation ("LEI"), LOWRANCE
CONTRACTS, INC., a Delaware corporation ("Lowrance Contracts"), and SEA
ELECTRONICS, INC., an Oklahoma corporation ("Sea Electronics") (Lowrance, LEI,
Lowrance Contracts and Sea Electronics are herein individually and collectively
called "Borrower").

                                    RECITALS

          A.  Borrower, Lowrance Australia Pty Limited ("Lowrance Australia")
and Lender have entered into that certain Loan and Security Agreement, dated
December 15, 1993, as amended by (i) that certain First Amendment to Loan and
Security Agreement, dated October 16, 1995, by and among Lender, Borrower and
Lowrance Australia, (ii) that certain Second Amendment to Loan and Security
Agreement, dated November 1, 1996 by and among Lender and Borrower, (iii) that
certain Third Amendment to Loan and Security Agreement, dated December 30, 1996,
by and among Lender and Borrower, (iv) that certain Fourth Amendment to Loan and
Security Agreement, entered into effective as of April 1, 1997, by and among
Lender and Borrower, (v) that certain Fifth Amendment to Loan and Security
Agreement, entered into effective as of August 25, 1997, by and between Lender
and Borrower ("Fifth Amendment"), (vi) that certain Sixth Amendment to Loan and
Security Agreement and Certain Other Loan Documents, entered into effective as
of August 28, 1997, by and between Lender and Borrower, (vii) that certain
Seventh Amendment to Loan and Security Agreement, entered into effective as of
November 1, 1996, by and between Lender and Borrower, (viii) that certain Eighth
Amendment to Loan and Security Agreement, made and entered into as of December
9, 1997, by and between Lender and Borrower, and (ix) that certain Ninth
Amendment to Loan and Security Agreement made and entered into as of September
14, 1998, by and between Lender and Borrower (as amended, the "Loan Agreement").

          B.  Borrower and Lender desire to amend the Loan Agreement and certain
of the other Loan Documents as hereinafter set forth.

          NOW, THEREFORE, in consideration of the premises herein contained and
other good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, the parties, intending to be legally bound, agree as
follows:

                                   ARTICLE I
                                  Definitions
                                  -----------

          1.01  Capitalized terms used in this Amendment are defined in the Loan
Agreement, as amended hereby, unless otherwise stated.

                                       1
<PAGE>
 
                                 ARTICLE II
                                 Amendments
                                 ----------

     2.01   Amendment to Section 1.1 of the Loan Agreement; Addition of
Certain Definitions.  Effective as of the date of execution of this Amendment,
Section 1.1 of the Loan Agreement is hereby amended by adding the following
definitions thereto in alphabetical order:

            "$4,800,000.02 Term Loan - the Loan described in Section 2.2(A-1) of
     this Agreement.

            $4,800,000.02 Term Note - that certain $4,000,000 Secured Promissory
     Note, dated August 25, 1997, executed by Borrower, in favor of Lender, as
     modified by the Tenth Amendment Agreement (which Tenth Amendment Agreement,
     among other things, increased the face principal amount of such promissory
     note to $4,800,000.02), as the same may be renewed, extended, modified and
     restated from time to time, together with promissory notes given in
     substitution therefore.

            Tenth Amendment Agreement - the Tenth Amendment to Loan and Security
     Agreement, executed in November of 1998 by Lender and Borrower."

     2.02   Amendment to Section 1.1 of the Loan Agreement; Deletion of Certain
Definitions.  Effective as of the date of execution of this Amendment, Section
1.1 of the Loan Agreement is hereby amended by deleting therefrom the
definitions of "$4,000,0000 Term Loan" and "$4,000,000 Term Note."

     2.03   Deleting References to "$4,000,000 Term Loan" in the Loan Agreement
and Substitution therefor of References to "$4,800,000.02 Term Loan."  Effective
as of the date of execution of this Amendment, all references in the Loan
Agreement to the term "$4,000,000 Term Loan" are hereby deleted and substituted
therefor are references to the term "$4,800,000.02 Term Loan."

     2.04   Deletion of References to "$4,000,000 Term Note" in Loan Agreement
and Substitution therefor of References to "$4,800,000.02 Term Note". Effective
as of the date of execution of this Amendment, all references in the Loan
Agreement to the term "$4,000,000 Term Note" are hereby deleted and substituted
therefor are references to the term "$4,800,000.02 Term Note."

     2.05   Amendment to Section 2.2 (A-1) of the Loan Agreement.  Effective
as of the date of execution of this Amendment, Section 2.2(A-1) of the Loan
Agreement is hereby amended and restated to read in its entirety as follows:

            "(A-1)  $4,800,000.02 Term Loan.  The parties hereto agree that
     effective as of August 25, 1997, Lender made to Borrower that certain term
     loan in the original principal amount of $4,000,000, evidenced by that
     certain $4,000,000 Secured Promissory Note, dated August 25, 1997, in the
     original principal amount of $4,000,000, executed by Borrower and payable
     to the order of Lender.  Borrower further agrees, represents and warrants
     that as of the date of execution of the Tenth Amendment Agreement, the
     unpaid principal amount of such term loan is $3,000,000.02, and that there
     are no claims or offsets against, or defenses or counterclaims to, payment
     of such amount to Lender.  Borrower further agrees, represents and warrants
     that it has requested that Lender make on the date of execution of the
     Tenth Amendment Agreement an additional $1,800,000 term loan to Borrower,
     the proceeds of which shall be used by 

                                       2
<PAGE>
 
     Borrower solely for purposes for which the proceeds of the Revolving Credit
     Loans are authorized to be used, and that such additional $1,800,000 term
     loan be combined and consolidated with the above-described existing term
     loan, such that the combined and consolidated term loan shall be in the
     aggregate principal amount of $4,800,000.02 (the `$4,800,000.02 Term Loan')
     which shall be repayable in accordance with the terms of the $4,800,000.02
     Term Note and shall be secured by the Collateral. Subject to the terms and
     conditions of this Agreement and the conditions precedent specified in the
     Tenth Amendment Agreement, Lender agrees to advance such additional
     $1,800,000 to Borrower on the date of execution of the Tenth Amendment
     Agreement."

     2.06   Amendment to Section 9.2(X) of the Loan Agreement.  Effective as
of the date of execution of this Amendment, Section 9.2(X) of the Loan Agreement
is amended and restated to read in its entirety as follows:

            "(X)  Leases.  Become a lessee under any operating lease (other
     than a lease under which Borrower is a lessor) of Property if the aggregate
     Rentals payable during any fiscal year of Borrower, beginning with fiscal
     year 1999, under the lease in question and all other leases under which the
     Borrower is then lessee would exceed $1,900,000.00.  The term `Rentals'
     means, as of the date of determination, all payments which the lessee is
     required to make by the terms of any lease."

     2.07   Amendment to Section 9.3 of the Loan Agreement.  Effective as of the
date of execution of this Amendment, Section 9.3 of the Loan Agreement is
amended and restated to read in its entirety as follows:

            "9.3  Specific Financial Covenants.  During the term of this
     Agreement, and thereafter for so long as there are any Obligations to
     Lender, Borrower covenants that, unless otherwise consented to by Lender in
     writing, it shall:

                  (A) Minimum Tangible Net Worth. Maintain a Consolidated
            Tangible Net Worth of not less than the amount indicated below on
            the last day of each calendar month during the period corresponding
            thereto:

<TABLE>
<CAPTION>
                                       PERIOD                                     AMOUNT
                                       ------                                     ------
            <S>  <C>                                                    <C>       <C>
            (a)  November 1, 1998 through November 30, 1998             (a)       $4,564,000
            (b)  December 1, 1998 through December 31, 1998             (b)       $4,477,000
            (c)  January 1, 1999 through January 31, 1999               (c)       $4,499,000
            (d)  February 1, 1999 through February 28, 1999             (d)       $5,201,000
            (e)  March 1, 1999 through March 31, 1999                   (e)       $5,834,000
            (f)  April 1, 1999 through April 30, 1999                   (f)       $6,420,000
            (g)  May 1, 1999 through May 31, 1999                       (g)       $6,698,000
            (h)  June 1, 1999 through June 30, 1999                     (h)       $6,833,000
            (i)  July 1, 1999 through July 31, 1999                     (i)       $6,890,000
            (j)  Thereafter                                             (j)       $7,000,000
</TABLE>

                  (B) Maximum Leverage Ratio. Maintain, on a Consolidated basis,
            a ratio of (i) total Indebtedness to (ii) Tangible Net Worth of not
            more than the ratio shown below as of the last day of each calendar
            month during the period corresponding thereto:

                                       3
<PAGE>
 
<TABLE>
<CAPTION>
                                 PERIOD                                        RATIO
                                 ------                                        -----
            <S>  <C>                                                     <C>  <C>
            (a)  November 1, 1998 through November 30, 1998              (a)  8.9 to 1.0
            (b)  December 1, 1998 through December 31, 1998              (b)  9.1 to 1.0
            (c)  January 1, 1999 through January 31, 1999                (c)  9.6 to 1.0
            (d)  February 1, 1999 through February 28, 1999              (d)  8.8 to 1.0
            (e)  March 1, 1999 through March 31, 1999                    (e)  8.0 to 1.0
            (f)  April 1, 1999 through April 30, 1999                    (f)  6.7 to 1.0
            (g)  May 1, 1999 through May 31, 1999                        (g)  6.3 to 1.0
            (h)  June 1, 1999 through June 30, 1999                      (h)  5.7 to 1.0
            (i)  July 1, 1999 and thereafter                             (i)  5.3 to 1.0
</TABLE>

                  (C) Fixed Charge Ratio. Maintain, on a Consolidated basis, a
             Fixed Charge Ratio of not less than the ratio shown below for the
             periods corresponding thereto.

<TABLE>
<CAPTION>
                            PERIOD                                    RATIO
                            ------                                    -----
     <S>                                                          <C>
     (a)  Six calendar month period ending on January 31,         (a)  0.4 to 1.0
          1999
     (b)  Nine calendar month period ending on April 30,          (b)  0.9 to 1.0
          1999
     (c)  Twelve calendar month period ending on July 31,         (c)  1.0 to 1.0
          1999
     (d)  Twelve calendar month period ending on the last         (d)  1.0 to 1.0
          day of each thereafter occurring October,
          January, April and July"
</TABLE>

     2.08   Amendment to Section 11.1(K) of the Loan Agreement. Effective as of
the date of execution of this Amendment, Section 11.1(K) of the Loan Agreement
is hereby amended and restated to read in its entirety as follows:

            "(K)  Change of Ownership.  Darrell J. Lowrance, or his estate in
     the case of his death, shall cease to own and control, beneficially and of
     record, at least 50.6% of the issued and outstanding capital stock of
     Borrower."

     2.09   Amendment to Section 11.1 of the Loan Agreement; Deletion of Section
11.1(Q).  Effective as of the date of execution of this Amendment, Section
11.1(Q), Additional $3,000,000 in Cash Equity by November 30, 1998, of the Loan
Agreement is hereby deleted.

     2.10   Amendment of $4,000,000 Secured Promissory Note. Effective as of the
date of execution of this Amendment, that certain $4,000,000 Secured Promissory
Note, dated August 25, 1997, in the original principal amount of $4,000,000,
payable to the order of Lender and executed by Borrower, is amended as follows:

            (i)   Each reference to the dollar amount "$4,000,000" is hereby
     deleted and substituted therefor is the dollar amount "$4,800,000.02".

                                       4
<PAGE>
 
            (ii)  Reference to the phrase "FOUR MILLION AND NO/100 DOLLARS" is
     hereby deleted and substituted therefor is the phrase "FOUR MILLION EIGHT
     HUNDRED THOUSAND AND 02/100 DOLLARS".

            (iii) Each reference to the phrase "$4,000,000 Term Loan" is
     deleted and substituted therefor is the phrase "$4,800,000.02 Term Loan".

            (iv)  The last paragraph on page one and the carryover paragraph
     on page two, which describes when and in what amount the principal amount
     and accrued interest on such promissory note shall be due and payable, is
     amended and restated to read in its entirety as follows:

                  "The principal amount of and accrued interest on this Note
            shall be due and payable on the dates and in the manner hereinafter
            set forth:

                         (a)   interest shall be due and payable monthly, in
                  arrears, on the first day of each month, commencing on
                  December 1, 1998, and continuing until such time as the full
                  principal balance, together with all other amounts owing
                  hereunder, shall have been paid in full; and

                         (b)   principal shall be due and payable as follows:

                               (i)  on the first day of each month, commencing
                         on March 1, 1999, and continuing thereafter on the
                         first day of each thereafter occurring month, in
                         monthly installments of $80,000.00 each; and

                               (ii) with the remaining principal being due and
                         payable in full on the last day of the Original Term
                         (or the last day of the Renewal Term if the Loan
                         Agreement is extended as provided in Section 3.2
                         thereof); or on any earlier termination of the Loan
                         Agreement by Lender or Borrower pursuant to Section 3.2
                         or Section 3.3 thereof."

     2.11   Restructuring Fee.  In consideration for the agreements of Lender
contained herein, including, without limitation, the advancing to Borrower of an
additional $1,800,000 on the date hereof, but subject to Section 3.1(D) of the
Loan Agreement, Borrower agrees to pay Lender a fee of $50,000.  Such fee shall
be fully earned as of the date hereof, and shall be payable upon the earlier to
occur of (i) March 1, 1999, (ii) termination of the Loan Agreement, or (iii)
payment in full of the Loans.  Borrower hereby irrevocably authorizes Lender, in
Lender's sole discretion, to advance to Borrower, and to charge on the earlier
to occur of (i) March 1, 1999, (ii) termination of the Loan Agreement, or (iii)
payment in full of the Loans, to Borrower's Loan Account hereunder as a
Revolving Credit Loan, a sum sufficient to pay in full this restructuring fee.
Notwithstanding the foregoing, payment of such $50,000 fee shall be waived by
Lender if, prior to March 1, 1999, Borrower shall have paid off in full, in
immediately available funds, the $1,800,000 loan advanced by Lender to Borrower
on the date hereof.

                                       5
<PAGE>
 
                                  ARTICLE III
                             Conditions Precedent

     3.01   Conditions Precedent.  The effectiveness of this Amendment is
subject to the satisfaction of the following conditions precedent, unless
specifically waived in writing by Lender:

            (a)   Lender shall have received each of the following, each in
     form and substance satisfactory to Lender: (i) this Amendment, duly
     executed by Borrower; and (ii) such additional documents, instruments and
     information as Lender or its legal counsel may request;

            (b)   The representations and warranties contained herein, in the
     Loan Agreement and in the other Loan Documents, as each is amended hereby,
     shall be true and correct as of the date hereof, as if made on the date
     hereof;

            (c)   After giving effect to this Amendment, no Default or Event of
     Default shall have occurred and be continuing, unless such Default or Event
     of Default has been specifically waived in writing by Lender; and

            (d)   All corporate proceedings taken in connection with the
     transactions contemplated by this Amendment and all documents, instruments
     and other legal matters incident thereto shall be satisfactory to Lender
     and its legal counsel.

                                   ARTICLE IV
                                 Limited Waiver
                                        
     Upon satisfaction of the conditions and covenants set forth in Section 3.01
of this Amendment, Lender hereby waives any Default or Event of Default which
occurred due to the violation by Borrower of the following covenants in the Loan
Agreement:

            (a)   The aggregate Rentals paid by Borrower as lessee under
     operating leases for fiscal year 1998, exceeded the maximum amount
     specified in Section 9.2(X) of the Loan Agreement, which is a violation of
     Section 9.2(X) of the Loan Agreement;

            (b)   Borrower respectively failed for the period beginning on
     August 1, 1998 and continuing through August 31, 1998, and the period
     beginning on September 1, 1998 and continuing through September 30, 1998,
     and the period beginning October 1, 1998 and continuing through October 31,
     1998, to maintain a Consolidated Tangible Net Worth of not less than the
     amount set forth in Section 9.3(A) of the Loan Agreement, each of which is
     a violation of Section 9.3(A) of the Loan Agreement;

            (c)   Borrower respectively failed for the period beginning on
     August 1, 1998, and continuing through August 31, 1998, and the period
     beginning on September 1, 1998, and continuing through September 30, 1998
     and the period beginning October 1, 1998 and continuing through October 31,
     1998, to maintain a ratio of total Indebtedness to Tangible Net Worth of
     not more than the ratio set forth in Section 9.3(B) of the Loan Agreement,
     each of which is a violation of Section 9.3(B) of the Loan Agreement; and

            (d)   Borrower failed to maintain for the three calendar month
     period ending on October 31, 1998, a Fixed Charge Ratio of not less than
     the ratio set forth in Section 9.3(C) of the Loan Agreement, which is a
     violation of Section 9.3(C) of the Loan Agreement.

                                       6
<PAGE>
 
     Except as otherwise specifically provided for in this Amendment, nothing
contained in this Amendment shall be construed as a waiver by Lender of any
covenant or provision of the Loan Agreement, the other Loan Documents, this
Amendment, or of any other contract or instrument between Borrower and Lender,
and the failure of Lender at any time or times hereafter to require strict
performance by Borrower of any provision thereof shall not waive, affect or
diminish any right of Lender to thereafter demand strict compliance therewith.
Lender hereby reserves all rights granted under the Loan Agreement, the other
Loan Documents, this Amendment and any other contract or instrument between
Borrower and Lender.

                                   ARTICLE V
                 Ratifications, Representations and Warranties

     5.01   Ratifications.  The terms and provisions set forth in this
Amendment shall modify and supersede all inconsistent terms and provisions set
forth in the Loan Agreement and the other Loan Documents, and, except as
expressly modified and superseded by this Amendment, the terms and provisions of
the Loan Agreement and the other Loan Documents are ratified and confirmed and
shall continue in full force and effect.  Borrower and Lender agree that the
Loan Agreement and the other Loan Documents, as amended hereby, shall continue
to be legal, valid, binding and enforceable in accordance with their respective
terms.

     5.02   Representations and Warranties.  Borrower hereby represents and
warrants to Lender that (a) the execution, delivery and performance of this
Amendment and any and all other Loan Documents executed and/or delivered in
connection herewith have been authorized by all requisite corporate action on
the part of Borrower and will not violate the Certificate of Incorporation or
Bylaws of Borrower; (b) the representations and warranties contained in the Loan
Agreement, as amended hereby, and any other Loan Documents are true and correct
on and as of the date hereof and on and as of the date of execution hereof as
though made on and as of each such date; (c) no Default or Event of Default
under the Loan Agreement, as amended hereby, has occurred and is continuing; (d)
Borrower is in full compliance with all covenants and agreements contained in
the Loan Agreement and the other Loan Documents, as amended hereby; (e) the
Borrower's Certificate of Incorporation and Bylaws are in full force and effect
on and as of the date hereof without modification or amendment in any respect
since November 1, 1996; (f) as of the date hereof, (i) Borrower is in existence
and in corporate and tax good standing in the State of its organization, (ii)
the Borrower is qualified to do business as a foreign corporation and is in
corporate and tax good standing in each jurisdiction where Borrower is doing
business and is required to be so qualified, (iii) Borrower does not owe
franchise taxes or other taxes required to maintain its corporate existence and
no franchise tax reports are due, and (iv) no proceedings are pending for
forfeiture of the Borrower's charter or for its dissolution either voluntarily
or involuntarily; and (g) the officer of Borrower executing this Amendment has
been duly elected and is, at present, qualified and acting in the office
indicated below such officer's name and is duly authorized to execute this
Amendment on behalf of Borrower.

                                       7
<PAGE>
 
                                  ARTICLE VI
                           Miscellaneous Provisions

     6.01   Survival of Representations and Warranties.  All representations
and warranties made in the Loan Agreement or any other Loan Document, including,
without limitation, any document furnished in connection with this Amendment,
shall survive the execution and delivery of this Amendment and the other Loan
Documents, and no investigation by Lender or any closing shall affect the
representations and warranties or the right of Lender to rely upon them.

     6.02   Reference to Loan Agreement.  Each of the Loan Agreement and the
other Loan Documents, and any and all other agreements, documents or instruments
now or hereafter executed and delivered pursuant to the terms hereof or pursuant
to the terms of the Loan Agreement, as amended hereby, are hereby amended so
that any reference in the Loan Agreement and such other Loan Documents to the
Loan Agreement shall mean a reference to the Loan Agreement, as amended hereby.

     6.03   Expenses of Lender.  As provided in the Loan Agreement, Borrower
agrees to pay on demand all costs and expenses incurred by Lender in connection
with the preparation, negotiation and execution of this Amendment and the other
Loan Documents executed pursuant hereto and any and all amendments,
modifications, and supplements thereto, including, without limitation, the costs
and fees of Lender's legal counsel, and all costs and expenses incurred by
Lender in connection with the enforcement or preservation of any rights under
the Loan Agreement, as amended hereby, or any other Loan Documents, including,
without, limitation, the costs and fees of Lender's legal counsel.

     6.04   Severability.  Any provision of this Amendment held by a court
of competent jurisdiction to be invalid or unenforceable shall not impair or
invalidate the remainder of this Amendment and the effect thereof shall be
confined to the provision so held to be invalid or unenforceable.

     6.05   Successors and Assigns.  This Amendment is binding upon and
shall inure to the benefit of Lender and Borrower and their respective
successors and assigns, except that Borrower may not assign or transfer any of
its rights or obligations hereunder without the prior written consent of Lender.

     6.06   Counterparts.  This Amendment may be executed in one or more
counterparts, each of which when so executed shall be deemed to be an original,
but all of which when taken together shall constitute one and the same
instrument.

     6.07   Effect of Waiver.  No consent or waiver, express or implied, by
Lender to or for any breach of or deviation from any covenant or condition by
Borrower shall be deemed a consent to or waiver of any other breach of the same
or any other covenant, condition or duty.

     6.08   Headings.  The headings, captions, and arrangements used in this
Amendment are for convenience only and shall not affect the interpretation of
this Amendment.

     6.09   Applicable Law.  THIS AMENDMENT AND ALL OTHER LOAN DOCUMENTS
EXECUTED PURSUANT HERETO SHALL BE DEEMED TO HAVE BEEN MADE AND TO BE PERFORMABLE
IN AND SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE
STATE OF TEXAS.

     6.10   Final Agreement.  THE LOAN AGREEMENT AND THE OTHER LOAN
DOCUMENTS, EACH AS AMENDED HEREBY, REPRESENT THE ENTIRE EXPRESSION OF THE
PARTIES WITH RESPECT TO THE SUBJECT MATTER HEREOF ON THE DATE THIS 

                                       8
<PAGE>
 
AMENDMENT IS EXECUTED. THE LOAN AGREEMENT AND THE OTHER LOAN DOCUMENTS, AS
AMENDED HEREBY, MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS OR
SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. THERE ARE NO UNWRITTEN ORAL
AGREEMENTS BETWEEN THE PARTIES. NO MODIFICATION, RESCISSION, WAIVER, RELEASE OR
AMENDMENT OF ANY PROVISION OF THIS AMENDMENT SHALL BE MADE, EXCEPT BY A WRITTEN
AGREEMENT SIGNED BY BORROWER AND LENDER.

     6.11   Release.  BORROWER HEREBY ACKNOWLEDGES THAT IT HAS NO DEFENSE,
COUNTERCLAIM, OFFSET, CROSS-COMPLAINT, CLAIM OR DEMAND OF ANY KIND OR NATURE
WHATSOEVER THAT CAN BE ASSERTED TO REDUCE OR ELIMINATE ALL OR ANY PART OF ITS
LIABILITY TO REPAY THE "OBLIGATIONS" OR TO SEEK AFFIRMATIVE RELIEF OR DAMAGES OF
ANY KIND OR NATURE FROM LENDER.  BORROWER HEREBY VOLUNTARILY AND KNOWINGLY
RELEASES AND FOREVER DISCHARGES LENDER, ITS PREDECESSORS, OFFICERS, DIRECTORS,
AGENTS, EMPLOYEES, SUCCESSORS AND ASSIGNS, FROM ALL POSSIBLE CLAIMS, DEMANDS,
ACTIONS, CAUSES OF ACTION, DAMAGES, COSTS, EXPENSES, AND LIABILITIES WHATSOEVER,
KNOWN OR UNKNOWN, ANTICIPATED OR UNANTICIPATED, SUSPECTED OR UNSUSPECTED, FIXED,
CONTINGENT, OR CONDITIONAL, AT LAW OR IN EQUITY, ORIGINATING IN WHOLE OR IN PART
ON OR BEFORE THE DATE THIS AMENDMENT IS EXECUTED, WHICH THE BORROWER MAY NOW OR
HEREAFTER HAVE AGAINST LENDER, ITS PREDECESSORS, OFFICERS, DIRECTORS, AGENTS,
EMPLOYEES, SUCCESSORS AND ASSIGNS, IF ANY, AND IRRESPECTIVE OF WHETHER ANY SUCH
CLAIMS ARISE OUT OF CONTRACT, TORT, VIOLATION OF LAW OR REGULATIONS, OR
OTHERWISE, AND ARISING FROM ANY "LOANS", INCLUDING, WITHOUT LIMITATION, ANY
CONTRACTING FOR, CHARGING, TAKING, RESERVING, COLLECTING OR RECEIVING INTEREST
IN EXCESS OF THE HIGHEST LAWFUL RATE APPLICABLE, THE EXERCISE OF ANY RIGHTS AND
REMEDIES UNDER THE LOAN AGREEMENT OR OTHER LOAN DOCUMENTS, AND THE NEGOTIATION
OF AND EXECUTION OF THIS AMENDMENT.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                       9
<PAGE>
 
     IN WITNESS WHEREOF, this Amendment has been executed and is effective as of
the date first above-written.


                                 "LENDER"

                                 FLEET CAPITAL CORPORATION


                                 By: /s/ Hance VanBeber
                                    ----------------------------------------
                                 Name: Hance VanBeber
                                      --------------------------------------
                                 Title: Vice President
                                       -------------------------------------


                                 "BORROWER"

                                 LOWRANCE ELECTRONICS, INC.


                                 By: /s/ Darrell J. Lowrance
                                    ----------------------------------------
                                    Darrell J. Lowrance, President


                                 LEI EXTRAS, INC.


                                 By: /s/ Steven L. Schneider
                                    ----------------------------------------
                                    Steven L. Schneider, President


                                 LOWRANCE CONTRACTS, INC.


                                 By: /s/ Terry R. Nimmo
                                    ----------------------------------------
                                    Terry R. Nimmo, Vice President


                                 SEA ELECTRONICS, INC.


                                 By: /s/ Steven L. Schneider
                                    ----------------------------------------
                                    Steven L. Schneider, President

                                       10