Exhibit 3.5

SECOND AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF

CLEANTECH ACQUISITION CORP.

CleanTech Acquisition Corp. (the “Corporation”), a corporation organized and existing under the General Corporation Law of the State of Delaware (the “DGCL”), does hereby certify as follows:

1. The name of the Corporation is CleanTech Acquisition Corp. The Corporation was incorporated under the name CleanTech Acquisition Corp. by the filing of its original Certificate of Incorporation with the Secretary of State of the State of Delaware on June 18, 2020 (the “Original Certificate”).

2. An Amended and Restated Certificate of Incorporation, which amended and restated the Original Certificate in its entirety, was filed with the Secretary of State of the State of Delaware on July 14, 2021 (as amended from time to time, the “Existing Certificate”).

3. This Second Amended and Restated Certificate of Incorporation (the “Second Amended and Restated Certificate”), which amends and restates the Existing Certificate in its entirety, has been approved by the Board of Directors of the Corporation (the “Board of Directors”) in accordance with Sections 242 and 245 of the DGCL and has been adopted by the stockholders of the Corporation at a meeting of the stockholders of the Corporation in accordance with the provisions of Section 211 of the DGCL.

4. The text of the Existing Certificate is hereby amended and restated by this Second Amended and Restated Certificate to read in its entirety as set forth in EXHIBIT A attached hereto.

5. This Second Amended and Restated Certificate shall become effective on the date of filing with the Secretary of State of the State of Delaware.

IN WITNESS WHEREOF, CleanTech Acqusition Corp. has caused this Second Amended and Restated Certificate to be signed by a duly authorized officer of the Corporation, on September 9, 2022.

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EXHIBIT A

ARTICLE I

NAME

The name of the corporation is Nauticus Robotics, Inc. (the “Corporation”).

ARTICLE II

REGISTERED OFFICE AND AGENT

The address of the Corporation’s registered office in the State of Delaware is c/o Corporation Service Company, 251 Little Falls Drive, in the City of Wilmington, County of New Castle, State of Delaware, 19808, and the name of its registered agent at such address is Corporation Service Company.

ARTICLE III

PURPOSE

The purpose of the Corporation is to engage in any lawful act or activity for which corporations may be organized under the General Corporation Law of the State of Delaware (the “DGCL”) as it now exists or may hereafter be amended and supplemented.

ARTICLE IV

CAPITAL STOCK

The Corporation is authorized to issue two classes of stock to be designated, respectively, “Common Stock” and “Preferred Stock.” The total number of shares of capital stock which the Corporation shall have authority to issue is 635,000,000. The total number of shares of Common Stock that the Corporation is authorized to issue is 625,000,000, having a par value of $0.0001 per share, and the total number of shares of Preferred Stock that the Corporation is authorized to issue is 10,000,000, having a par value of $0.0001 per share.

The designations and the powers, privileges and rights, and the qualifications, limitations or restrictions thereof in respect of each class of capital stock of the Corporation are as follows:

1. General. The voting, dividend, liquidation, and other rights and powers of the Common Stock are subject to and qualified by the rights, powers and preferences of any series of Preferred Stock as may be designated by the Board of Directors of the Corporation (the “Board of Directors”) and outstanding from time to time.

2. Voting. Except as otherwise provided herein or expressly required by law, each holder of Common Stock, as such, shall be entitled to vote on each matter submitted to a vote of stockholders and shall be entitled to one (1) vote for each share of Common Stock held of record by such holder as of the record date for determining stockholders entitled to vote on such matter. Except as otherwise required by law, holders of Common Stock, as such, shall not be entitled to vote on any amendment to this Second Amended and Restated Certificate (including any Certificate of Designation (as defined below)) that relates solely to the rights, powers, preferences (or the qualifications, limitations or restrictions thereof) or other terms of one or more outstanding series of Preferred Stock if the holders of such affected series are entitled, either separately or together with the holders of one or more other such series, to vote thereon pursuant to this Second Amended and Restated Certificate (including any Certificate of Designation) or pursuant to the DGCL.

Subject to the rights of any holders of any outstanding series of Preferred Stock, the number of authorized shares of Common Stock may be increased or decreased (but not below the number of shares thereof then outstanding) by the affirmative vote of the holders of a majority of the stock of the Corporation entitled to vote, irrespective of the provisions of Section 242(b)(2) of the DGCL.

3. Dividends. Subject to applicable law and the rights and preferences of any holders of any outstanding series of Preferred Stock, the holders of Common Stock, as such, shall be entitled to the payment of dividends on the Common Stock when, as and if declared by the Board of Directors in accordance with applicable law.

4. Liquidation. Subject to the rights and preferences of any holders of any shares of any outstanding series of Preferred Stock, in the event of any liquidation, dissolution or winding up of the Corporation, whether voluntary or involuntary, the funds and assets of the Corporation that may be legally distributed to the Corporation’s stockholders shall be distributed among the holders of the then outstanding Common Stock pro rata in accordance with the number of shares of Common Stock held by each such holder.

Shares of Preferred Stock may be issued from time to time in one or more series, each of such series to have such terms as stated or expressed herein and in the resolution or resolutions providing for the creation and issuance of such series adopted by the Board of Directors as hereinafter provided.

Authority is hereby expressly granted to the Board of Directors from time to time to issue the Preferred Stock in one or more series, and in connection with the creation of any such series, by adopting a resolution or resolutions providing for the issuance of the shares thereof and by filing a certificate of designation relating thereto in accordance with the DGCL (a “Certificate of Designation”), to determine and fix the number of shares of such series and such voting powers, full or limited, or no voting powers, and such designations, preferences and relative participating, optional or other special rights, and qualifications, limitations or restrictions thereof, including without limitation thereof, dividend rights, conversion rights, redemption privileges and liquidation preferences, and to increase or decrease (but not below the number of shares of such series then outstanding) the number of shares of any series as shall be stated and expressed in such resolutions, all to the fullest extent now or hereafter permitted by the DGCL. Without limiting the generality of the foregoing, the resolution or resolutions providing for the creation and issuance of any series of Preferred Stock may provide that such series shall be superior or rank equally or be junior to any other series of Preferred Stock to the extent permitted by law and this Second Amended and Restated Certificate (including any Certificate of Designation). Except as otherwise required by law, holders of any series of Preferred Stock shall be entitled only to such voting rights, if any, as shall expressly be granted thereto by this Second Amended and Restated Certificate (including any Certificate of Designation).

The number of authorized shares of Preferred Stock may be increased or decreased (but not below the number of shares thereof then outstanding) by the affirmative vote of the holders of a majority of the stock of the Corporation entitled to vote, irrespective of the provisions of Section 242(b)(2) of the DGCL.

ARTICLE V

BOARD OF DIRECTORS

For the management of the business and for the conduct of the affairs of the Corporation it is further provided that:

A. Subject to the special rights of the holders of one or more outstanding series of Preferred Stock to elect directors, the initial directors of the Corporation shall be classified with respect to the time for which they severally hold office into three classes, designated as Class I, Class II and Class III. The initial Class I directors shall serve for a term expiring at the first annual meeting of the stockholders following the date of this Second Amended and Restated Certificate; the initial Class II directors shall serve for a term expiring at the second annual meeting of the stockholders following the date of this Second Amended and Restated Certificate; and the initial Class III directors shall serve for a term expiring at the third annual meeting following the date of this Second Amended and Restated Certificate. At each annual meeting of the stockholders of the Corporation beginning with the first annual meeting of the stockholders following the date of this Second Amended and Restated Certificate, subject to the special rights of the holders of one or more outstanding series of Preferred Stock to elect directors, the successors of the class of directors whose term expires at that meeting shall be elected to hold office for a term expiring at the annual meeting of the stockholders held in the third year following the year of their election. Each director shall hold office until his or her successor is duly elected and qualified or until his or her earlier death, resignation, disqualification or removal. No decrease in the number of directors shall shorten the term of any incumbent director. The Board of Directors is authorized to assign members of the Board of Directors already in office to Class I, Class II and Class III.

B. Except as otherwise expressly provided by the DGCL or this Second Amended and Restated Certificate, the business and affairs of the Corporation shall be managed by or under the direction of the Board of Directors. The number of directors which shall constitute the whole Board of Directors shall be fixed exclusively by one or more resolutions adopted from time to time by the Board of Directors.

C. Subject to the special rights of the holders of one or more outstanding series of Preferred Stock to elect directors, the Board of Directors or any individual director may be removed from office at any time, but only for cause and only by the affirmative vote of the holders of at least two-thirds (66 and 2/3%) of the voting power of all of the then outstanding shares of voting stock of the Corporation entitled to vote at an election of directors.

D. Subject to the special rights of the holders of one or more outstanding series of Preferred Stock to elect directors, except as otherwise provided by law, any vacancies on the Board of Directors resulting from death, resignation, disqualification, retirement, removal or other causes and any newly created directorships resulting from any increase in the number of directors shall be filled exclusively by the affirmative vote of a majority of the directors then in office, even though less than a quorum, or by a sole remaining director (other than any directors elected by the separate vote of one or more outstanding series of Preferred Stock), and shall not be filled by the stockholders. Any director appointed in accordance with the preceding sentence shall hold office until the expiration of the term to which such director shall have been appointed or until his or her earlier death, resignation, retirement, disqualification, or removal.

E. Whenever the holders of any one or more series of Preferred Stock issued by the Corporation shall have the right, voting separately as a series or separately as a class with one or more such other series, to elect directors at an annual or special meeting of stockholders, the election, term of office, removal and other features of such directorships shall be governed by the terms of this Second Amended and Restated Certificate (including any Certificate of Designation). Notwithstanding anything to the contrary in this Article V, the number of directors that may be elected by the holders of any such series of Preferred Stock shall be in addition to the number fixed pursuant to paragraph B of this Article V, and the total number of directors constituting the whole Board of Directors shall be automatically adjusted accordingly. Except as otherwise provided in the Certificate of Designation(s) in respect of one or more series of Preferred Stock, whenever the holders of any series of Preferred Stock having such right to elect additional directors are divested of such right pursuant to the provisions of such Certificate of Designation(s), the terms of office of all such additional directors elected by the holders of such series of Preferred Stock, or elected to fill any vacancies resulting from the death, resignation, disqualification or removal of such additional directors, shall forthwith terminate (in which case each such director thereupon shall cease to be qualified as, and shall cease to be, a director) and the total authorized number of directors of the Corporation shall automatically be reduced accordingly.

F. In furtherance and not in limitation of the powers conferred by statute, the Board of Directors is expressly authorized to adopt, amend or repeal the Amended and Restated Bylaws of the Corporation (as amended and/or restated from time to time, the “Bylaws”). In addition to any vote of the holders of any class or series of stock of the Corporation required by applicable law or by this Second Amended and Restated Certificate (including any Certificate of Designation in respect of one or more series of Preferred Stock) or the Bylaws of the Corporation, the adoption, amendment or repeal of the Bylaws of the Corporation by the stockholders of the Corporation shall require the affirmative vote of the holders of at least two-thirds (66 and 2/3%) of the voting power of all of the then outstanding shares of voting stock of the Corporation entitled to vote generally in an election of directors.

G. The directors of the Corporation need not be elected by written ballot unless the Bylaws so provide.

ARTICLE VI

STOCKHOLDERS

A. Any action required or permitted to be taken by the stockholders of the Corporation must be effected at an annual or special meeting of the stockholders of the Corporation, and shall not be taken by written consent in lieu of a meeting. Notwithstanding the foregoing, any action required or permitted to be taken by the holders of any series of Preferred Stock, voting separately as a series or separately as a class with one or more other such series, may be taken without a meeting, without prior notice and without a vote, to the extent expressly so provided by the applicable Certificate of Designation relating to such series of Preferred Stock, if a consent or consents in writing, setting forth the action so taken, shall be signed by the holders of outstanding shares of the relevant series of Preferred Stock having not less than the minimum number of votes that would be necessary to authorize or take such action at a meeting at which all shares entitled to vote thereon were present and voted and shall be delivered to the Corporation in accordance with the applicable provisions of the DGCL.

B. Subject to the special rights of the holders of one or more series of Preferred Stock, special meetings of the stockholders of the Corporation may be called, for any purpose or purposes, at any time only by or at the direction of the Board of Directors, the Chairperson of the Board of Directors, the Chief Executive Officer or the President, and shall not be called by any other person or persons.

C. Advance notice of stockholder nominations for the election of directors and of other business proposed to be brought by stockholders before any meeting of the stockholders of the Corporation shall be given in the manner provided in the Bylaws of the Corporation.

ARTICLE VII

LIABILITY

No director of the Corporation shall have any personal liability to the Corporation or its stockholders for monetary damages for any breach of fiduciary duty as a director, except to the extent such exemption from liability or limitation thereof is not permitted under the DGCL as the same exists or hereafter may be amended. Any amendment, repeal or modification of this Article VII, or the adoption of any provision of the Second Amended and Restated Certificate inconsistent with this Article VII, shall not adversely affect any right or protection of a director of the Corporation with respect to any act or omission occurring prior to such amendment, repeal, modification or adoption. If the DGCL is amended after approval by the stockholders of this Article VII to authorize corporate action further eliminating or limiting the personal liability of directors, then the liability of a director of the Corporation shall be eliminated or limited to the fullest extent permitted by the DGCL as so amended.

ARTICLE VIII

INDEMNIFICATION

The Corporation shall have the power to provide rights to indemnification and advancement of expenses to its current and former officers, directors, employees and agents and to any person who is or was serving at the request of the Corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise.

ARTICLE IX

AMENDMENTS

A. Notwithstanding anything contained in this Second Amended and Restated Certificate to the contrary, in addition to any vote required by applicable law, the following provisions in this Second Amended and Restated Certificate may be amended, altered, repealed or rescinded, in whole or in part, or any provision inconsistent therewith or herewith may be adopted, only by the affirmative vote of the holders of at least two- thirds (66 and 2/3%) of the total voting power of all the then outstanding shares of stock of the Corporation entitled to vote thereon, voting together as a single class: Part B of Article IV, Article V, Article VI, Article VII, Article VIII, and this Article IX.

B. If any provision or provisions of this Second Amended and Restated Certificate shall be held to be invalid, illegal or unenforceable as applied to any circumstance for any reason whatsoever: (i) the validity, legality and enforceability of such provisions in any other circumstance and of the remaining provisions of this Second Amended and Restated Certificate (including, without limitation, each portion of any paragraph of this Second Amended and Restated Certificate containing any such provision held to be invalid, illegal or unenforceable that is not itself held to be invalid, illegal or unenforceable) shall not, to the fullest extent permitted by applicable law, in any way be affected or impaired thereby and (ii) to the fullest extent permitted by applicable law, the provisions of this Second Amended and Restated Certificate (including, without limitation, each such portion of any paragraph of this Second Amended and Restated Certificate containing any such provision held to be invalid, illegal or unenforceable) shall be construed so as to permit the Corporation to protect its directors, officers, employees and agents from personal liability in respect of their good faith service to or for the benefit of the Corporation to the fullest extent permitted by law.

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