<PAGE>

                                                                     EXHIBIT 4.7

         FIRST AMENDMENT TO NATCO GROUP PROFIT SHARING AND SAVINGS PLAN

               (AS AMENDED AND RESTATED EFFECTIVE JANUARY 1, 2002)

         WHEREAS, the National Tank Company has heretofore adopted the NATCO
Group Profit Sharing and Savings Plan (As Amended and Restated Effective January
1, 2002) (the "Plan"); and

         WHEREAS, pursuant to Section 16.1 of the Plan, the Plan Administrative
Committee (the "Committee") has the authority to adopt amendments to the Plan
that do not have a significant cost impact on the Employers; and

         WHEREAS, the Committee desires to amend the Plan on behalf of the
Company and the other participating Employers to reflect certain legislative and
regulatory developments and to implement certain design changes.

         NOW, THEREFORE, the Plan is amended as follows and such amendments
shall supersede the provisions of the Plan to the extent those provisions are
inconsistent with the provisions of such amendments:

I.       Effective as of January 1, 2002:

                           1.       The reference to "5%" in the first sentence
                  of Section 3.1(a) of the Plan shall be deleted and the
                  reference to "1%" shall be substituted therefor.

                           2.       The phrase "and Paragraph (g) above" shall
                  be added to the first sentence of Section 3.1(h) of the Plan
                  after the parenthetical phrase "(as adjusted pursuant to
                  Paragraph (f) above)" contained therein.

                           3.       The first two sentences of Section 3.7(a) of
                  the Plan shall be deleted and the following shall be
                  substituted therefor:

         "Rollover Contributions may be made to the Plan by any Eligible
         Employee of amounts received by such Eligible Employee from a qualified
         plan described in section 401(a) or 403(a) of the Code, an annuity
         contract described in section 403(b) of the Code or an eligible plan
         under section 457(b) of the Code which is maintained by a state,
         political subdivision of a state, or any agency or instrumentality of a
         state or political subdivision of a state; provided, however, that the
         Plan will not accept a Rollover Contribution of any after-tax employee
         contributions from any source. In addition, the Plan will accept a
         Rollover Contribution of the portion of a distribution received by an
         Eligible Employee from an individual retirement account or annuity
         described in section 408(a) or 408(b) of the Code that is eligible to
         be rolled over and would otherwise be includable in gross income.
         Rollover Contributions may only be made to the Plan pursuant to and in
         accordance with applicable provisions of the Code. Any Eligible
         Employee desiring to effect Rollover Contributions must execute and
         file with the Committee the form described by the Committee for such
         purpose. A Rollover Contribution shall be credited to the Rollover
         Account of the Eligible Employee making such Rollover Contribution as
         of the day on which the Rollover Contribution is made. Qualified direct
         Rollover Contributions may be made to the Plan by any Eligible Employee
         of amounts received by such Eligible Employee from any of a qualified
         plan described in section 401(a) or 403(a) of the Code (excluding
         after-tax employee contributions), an annuity described in section
         403(b) of the Code but excluding after-tax employee contributions or an
         eligible plan under section 457(b) of the Code which is maintained by a
         state, political subdivision of a state, or any agency or
         instrumentality of a state or political subdivision of a state.
         Qualified direct Rollover Contributions may be made to the Plan only
         pursuant to and in accordance with applicable provisions of the Code
         and Treasury regulations promulgated thereunder. A direct Rollover
         Contribution of amounts that are `eligible rollover distributions'
         within the meaning of section 402(f)(2)(a) of the Code may be made to
         the Plan irrespective of whether such eligible rollover distribution
         was paid to the Eligible Employee or paid to the Plan as a `direct'
         Rollover Contribution."

<PAGE>

         4.       The last sentence of Section 11.1(c) of the Plan shall be
deleted.

II. Effective as of December 20, 2002:

         1.       The first two lines of Section 1.1(12)(C) of the Plan shall be
deleted and the following shall be substituted therefor:

                  "(C)The Compensation of any Participant taken into account for
                  purposes of the Plan, except for purposes of the application
                  of the limitations under sections 402(g) and 414(v) of the
                  Code, as described, respectively, in Sections 4.5 and 3.1(d)
                  of the Plan, shall be limited to $200,000 for any Plan Year
                  with such limitation to be:"

         2.       The second sentence of Section 3.1(b) of the Plan shall be
deleted and the following shall be substituted therefor:

      "A Participant who has elected to defer a portion of his Compensation may
         change his deferral election percentage (within the percentage limits
         set forth in Paragraph (a) above), effective as of the first day of any
         payroll period, by communicating such new deferral election percentage
         to his Employer in the manner and within the time period prescribed by
         the Committee."

         3.       Section 7.2 of the Plan shall be deleted and the following
shall be substituted therefor:

                  "7.2 TOTAL AND PERMANENT DISABILITY DETERMINED. A Participant
         shall be considered totally and permanently disabled if such
         Participant has been determined to be disabled under any
         Company-sponsored long-term disability plan, or if such Participant is
         not eligible for coverage under any such plan, then such Participant
         shall be considered totally and permanently disabled if such
         Participant has been determined eligible to receive Social Security
         disability benefits under the federal Social Security Act."

III. Effective as of January 1, 2003, the following new Section 10.7 shall be
added to Article X of the Plan:

                  "10.7    MINIMUM DISTRIBUTION REQUIREMENTS.

                  (a)      The provisions of this Section 10.7 will apply for
         purposes of determining required minimum distributions for calendar
         years beginning with the 2003 Distribution Calendar Year.

                  (b)      The requirements of this Section 10.7 will take
         precedence over any inconsistent provisions of the Plan.

                  (c)      All distributions required under this Section 10.7
         will be determined and made in accordance with the Treasury regulations
         under section 401(a)(9) of the Code.

                  (d)      Notwithstanding the other provisions of this Section
         10.7, distributions may be made under a designation made before January
         1, 1984, in accordance with section 242(b)(2) of the Tax Equity and
         Fiscal Responsibility Act (TEFRA) and the provisions of the Plan that
         relate to section 242(b)(2) of TEFRA.

                  (e)      The Participant's entire interest will be
         distributed, or begin to be distributed, to the Participant no later
         than the Participant's Required Beginning Date. If the Participant dies
         before distributions begin, the Participant's entire interest will be
         distributed, or begin to be distributed, no later than as follows:

                           (1)      If the Participant's surviving spouse is the
                  Participant's sole Designated Beneficiary, then distributions
                  to the surviving spouse will begin by December 31 of the
                  calendar year immediately following the calendar year in which
                  the Participant died, or

                                      -2-

<PAGE>

                  by December 31 of the calendar year in which the Participant
                  would have attained age 70 1/2, if later.

                           (2)      If the Participant's surviving spouse is not
                  the Participant's sole Designated Beneficiary, then
                  distributions to the Designated Beneficiary will begin by
                  December 31 of the calendar year immediately following the
                  calendar year in which the Participant died.

                           (3)      If there is no Designated Beneficiary as of
                  September 30 of the year following the year of the
                  Participant's death, the Participant's entire interest will be
                  distributed by December 31 of the calendar year containing the
                  fifth anniversary of the Participant's death.

                           (4)      If the Participant's surviving spouse is the
                  Participant's sole Designated Beneficiary and the surviving
                  spouse dies after the Participant but before distributions to
                  the surviving spouse begin, this Paragraph (disregarding item
                  (1) above), will apply as if the surviving spouse were the
                  Participant.

         For purposes of this Paragraph (e) and Paragraph (g) below, unless item
         (4) above applies, distributions are considered to begin on the
         Participant's Required Beginning Date. If item (4) above applies,
         distributions are considered to begin on the date distributions are
         required to begin to the surviving spouse under item (1) above. If
         distributions under an annuity purchased from an insurance company
         irrevocably commence to the Participant before the Participant's
         Required Beginning Date (or to the Participant's surviving spouse
         before the date distributions are required to begin to the surviving
         spouse under item (1) above), the date distributions are considered to
         begin is the date distributions actually commence. Unless the
         Participant's interest is distributed in the form of an annuity
         purchased from an insurance company or in a single sum on or before the
         Required Beginning Date, as of the first Distribution Calendar Year
         distributions will be made in accordance with Paragraphs (f) and (g) of
         this Section 10.7, whichever is applicable. If the Participant's
         interest is distributed in the form of an annuity purchased from an
         insurance company, distributions thereunder will be made in accordance
         with the requirements of section 401(a)(9) of the Code and the Treasury
         regulations.

                  (f)      During the Participant's lifetime, the minimum amount
         that will be distributed for each Distribution Calendar Year is the
         lesser of:

                           (1)      the quotient obtained by dividing the
                  Participant's Account Balance by the distribution period in
                  the Uniform Lifetime Table set forth in section 1.401(a)(9)-9
                  of the Treasury regulations, using the Participant's age as of
                  the Participant's birthday in the Distribution Calendar Year;
                  or

                           (2)      if the Participant's sole Designated
                  Beneficiary for the Distribution Calendar Year is the
                  Participant's spouse, the quotient obtained by dividing the
                  Participant's Account Balance by the number in the Joint and
                  Last Survivor Table set forth in section 1.401(a)(9)-9 of the
                  Treasury regulations, using the Participant's and spouse's
                  attained ages as of the Participant's and spouse's birthdays
                  in the Distribution Calendar Year.

         Required minimum distributions will be determined under this Paragraph
         (f) beginning with the first Distribution Calendar Year and up to and
         including the Distribution Calendar Year that includes the
         Participant's date of death.

                  (g)      If the Participant dies on or after the date
         distributions begin and there is a Designated Beneficiary, the minimum
         amount that will be distributed for each Distribution Calendar Year
         after the year

                                      -3-

<PAGE>

         of the Participant's death is the quotient obtained by dividing the
         Participant's Account Balance by the longer of the remaining Life
         Expectancy of the Participant or the remaining Life Expectancy of the
         Participant's Designated Beneficiary, determined as follows:

                           (1)      The Participant's remaining Life Expectancy
                  is calculated using the age of the Participant in the year of
                  death, reduced by one for each subsequent year.

                           (2)      If the Participant's surviving spouse is the
                  Participant's sole Designated Beneficiary, the remaining Life
                  Expectancy of the surviving spouse is calculated for each
                  Distribution Calendar Year after the year of the Participant's
                  death using the surviving spouse's age as of the spouse's
                  birthday in that year. For Distribution Calendar Years after
                  the year of the surviving spouse's death, the remaining Life
                  Expectancy of the surviving spouse is calculated using the age
                  of the surviving spouse as of the spouse's birthday in the
                  calendar year of the spouse's death, reduced by one for each
                  subsequent calendar year.

                           (3)      If the Participant's surviving spouse is not
                  the Participant's sole Designated Beneficiary, the Designated
                  Beneficiary's remaining Life Expectancy is calculated using
                  the age of the Designated Beneficiary in the year following
                  the year of the Participant's death, reduced by one for each
                  subsequent year.

         If the Participant dies on or after the date distributions begin and
         there is no Designated Beneficiary as of September 30 of the year after
         the year of the Participant's death, the minimum amount that will be
         distributed for each Distribution Calendar Year after the year of the
         Participant's death is the quotient obtained by dividing the
         Participant's Account Balance by the Participant's remaining Life
         Expectancy calculated using the age of the Participant in the year of
         death, reduced by one for each subsequent year.

                  (h)      If the Participant dies before the date distributions
         begin and there is a Designated Beneficiary, the minimum amount that
         will be distributed for each Distribution Calendar Year after the year
         of the Participant's death is the quotient obtained by dividing the
         Participant's Account Balance by the remaining Life Expectancy of the
         Participant's Designated Beneficiary, determined as provided in item
         (1), (2) or (3) of Paragraph (g), whichever is applicable. If the
         Participant dies before the date distributions begin and there is no
         Designated Beneficiary as of September 30 of the year following the
         year of the Participant's death, distribution of the Participant's
         entire interest will be completed by December 31 of the calendar year
         containing the fifth anniversary of the Participant's death. If the
         Participant dies before the date distributions begin, the Participant's
         surviving spouse is the Participant's sole Designated Beneficiary, and
         the surviving spouse dies before distributions are required to begin to
         the surviving spouse under item (1) of Paragraph (e), this Paragraph
         (h) will apply as if the surviving spouse were the Participant.
         Notwithstanding the foregoing, if the Participant dies before
         distributions begin and there is a Designated Beneficiary, distribution
         to the Designated Beneficiary is not required to begin by the date
         specified in Paragraph (e) above but the Participant's entire interest
         will be distributed to the Designated Beneficiary by December 31 of the
         calendar year containing the fifth anniversary of the Participant's
         death. If the Participant's surviving spouse is the Participant's sole
         Designated Beneficiary and the surviving spouse dies after the
         Participant but before distributions to either the Participant or the
         surviving spouse begin, this Paragraph will apply as if the surviving
         spouse were the Participant.

                  (i)      For purposes of this Section 10.7, the following
         terms and phrases shall have these respective meanings:

                           (1)      Designated Beneficiary: The individual who
                  is designated as a Participant's beneficiary under Section 9.2
                  of the Plan and is a Designated Beneficiary under section
                  401(a)(9) of the Code and section 1.401(a)(9)-1, Q&A-4,of the
                  Treasury regulations.

                                      -4-

<PAGE>

                           (2)      Distribution Calendar Year: A calendar year
                  for which a minimum distribution is required. For
                  distributions beginning before the Participant's death, the
                  first Distribution Calendar Year is the calendar year
                  immediately preceding the calendar year which contains the
                  Participant's Required Beginning Date. For distributions
                  beginning after the Participant's death, the first
                  Distribution Calendar Year is the calendar year in which
                  distributions are required to begin under Paragraph (e). The
                  required minimum distribution for the Participant's first
                  Distribution Calendar Year will be made on or before the
                  Participant's Required Beginning Date. The required minimum
                  distribution for other Distribution Calendar Years, including
                  the required minimum distribution for the Distribution
                  Calendar Year in which the Participant's Required Beginning
                  Date occurs, will be made on or before December 31 of that
                  Distribution Calendar Year.

                           (3)      Life Expectancy. Life Expectancy as computed
                  by use of the Single Life Table in section 1.401(a)(9)-9 of
                  the Treasury regulations.

                           (4)      Participant's Account Balance. The balance
                  in a Participant's Accounts as of the last Valuation Date in
                  the calendar year immediately preceding the Distribution
                  Calendar Year (valuation calendar year) increased by the
                  amount of any contributions made and allocated or forfeitures
                  allocated to the Participant's Accounts as of dates in the
                  valuation calendar year after the Valuation Date and decreased
                  by distributions made in the valuation calendar year after the
                  Valuation Date. A Participant's Account Balance for the
                  valuation calendar year includes any amounts rolled over or
                  transferred to the Plan either in the valuation calendar year
                  or in the Distribution Calendar Year if distributed or
                  transferred in the valuation calendar year.

                           (5)      Requiring Beginning Date. With respect to a
                  Participant or beneficiary, the date described in Section
                  10.1(d) of the Plan."

IV. As amended hereby, the Plan is specifically ratified and reaffirmed.

         IN WITNESS WHEREOF, the party has caused these presents to be executed
this 20th day of December, 2002.

                           NATIONAL TANK COMPANY

                           By: /s/ DAVID F. WALKER
                               ------------------------------
                           Name:  David F. Walker
                                 ----------------------------
                           Title: Director of Human Resources
                                 ----------------------------


                                      -5-