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                             May 18, 2022

       Eli Spiro
       Chairman and Chief Executive Officer
       CleanTech Acquisition Corp.
       207 West 25th Street, 9th Floor
       New York, NY 10001

                                                        Re: Cleantech
Acquisition Corp.
                                                            Amendment No. 2 to
Registration Statement on Form S-4
                                                            Filed April 27,
2022
                                                            File No. 333-262431

       Dear Mr. Spiro:

             We have reviewed your amended registration statement and have the
following
       comments. In some of our comments, we may ask you to provide us with
information so we
       may better understand your disclosure.

              Please respond to this letter by amending your registration
statement and providing the
       requested information. If you do not believe our comments apply to your
facts and
       circumstances or do not believe an amendment is appropriate, please tell
us why in your
       response.

              After reviewing any amendment to your registration statement and
the information you
       provide in response to these comments, we may have additional comments.
Unless we note
       otherwise, our references to prior comments are to comments in our April
22, 2022 letter.

       Amendment No. 2 to Registration Statement on Form S-4

       General

   1.                                                   We note your response
to prior comment 29. Given that your planned Robotics as a
                                                        Service (RaaS) model is
not yet offered and you do not plan to launch it until late 2022,
                                                        please revise
throughout this filing to clearly disclose everywhere you discuss the RaaS
                                                        model that this is a
planned, future service to be offered and that it is not currently
                                                        available. For example,
on pages 21 and 22 where you discuss your various products you
                                                        state they are
currently offered under the RaaS model. If true, revise to clarify that you
                                                        intend these to be
offered under the RaaS model when available.
 Eli Spiro
FirstName
CleanTech LastNameEli   Spiro
           Acquisition Corp.
Comapany
May        NameCleanTech Acquisition Corp.
     18, 2022
May 18,
Page 2 2022 Page 2
FirstName LastName
Q: Do any of CLAQ's directors or officers have interests that may conflict with
my interests with
respect to the Business Combination?, page 11

2.       We note your response to prior comment 5. Advise if the amounts you
disclose include
         the Private Warrants held by your Co-Sponsors, which you note have a
market value of
         $4.02 million. Clarify that your disclosure of the "aggregate" amount
contingent upon
         closing the Business Combination includes the current value of
securities held (including
         any warrants), loans extended, fees due and out-of-pocket expenses for
which the Co-
         Sponsors and their affiliates are awaiting reimbursement. Revise or
advise, as
         appropriate.
3.       We note your response to prior comment 6. Disclose, in the aggregate,
the fees payable to
         Chardan Capital Markets, LLC that are contingent upon completion of
the business
         combination, including any loans extended, fees due and out-of-pocket
expenses.
Summary of the Proxy Statement/Prospectus
Services and Revenue, page 23

4.       We note the table on page 24 includes projected 2021 revenue that does
not agree with
         your actual historical 2021 revenue. Please revise to disclose the
actual revenue amounts
         for fiscal 2021. Also, revise to disclose the amount of estimated RaaS
model revenue
         included in your 2024 estimated service revenue.
5.       Advise whether Nauticus' projected revenues disclosed on page 24 are
subject to the same
         qualifications and assumptions that apply to its revenue projections
on page 107 and, if so,
         make the appropriate revisions in your disclosure. Further, tell us
whether the added
         projections were prepared as part of the projected financial
information that Nauticus
         provided to CLAQ prior to its approval of the Business Combination.
6.       We note your response to prior comment 7. To help investors better
understand your
         RaaS model, please provide a definition in your summary that is
consistent with your
         disclosures. For example, on page 108 you state that "One such example
is the Nauticus
         RaaS model which bills out at a rate of $40,000 per day and covers all
costs associated
         with that operation," but do not appear to refer to this figure
elsewhere. Advise if the
         $40,000 per day fee is the same for access to the Aquanaut, Argonaut,
Hydronaut and
         your other robotics and whether it includes access to your ToolKITT.
When you
         introduce your RaaS model on page 21, clarify what you anticipate the
service will offer,
         including the costs the RaaS model is expected to cover for a
subscriber and
         whether Nauticus will be responsible for maintenance and servicing of
the units, either
         directly or by coordinating with third-party servicers and other
providers.
 Eli Spiro
FirstName
CleanTech LastNameEli   Spiro
           Acquisition Corp.
Comapany
May        NameCleanTech Acquisition Corp.
     18, 2022
May 18,
Page 3 2022 Page 3
FirstName LastName
Securities Purchase Agreement, page 28

7.       We note you have filed a letter agreement as Exhibit 10.14.1 that
appears to indicate that
         ATW's subscription to the Debentures in the aggregate principal amount
of $37,959,184 is
         dependent on the investment of $5,000,000 by Material Impact Fund II,
L.P. and the
         consummation of a secured convertible term loan with Nauticus. Advise
or revise your
         disclosure.
Ownership of the Post-Business Combination Company After the Closing, page 31

8.       We note your response to prior comment 9 and your revised disclosure
on page 33. Please
         provide additional disclosure about the purpose for seeking these
financial advisory
         services. In that regard, we note your disclosure that CLAQ is seeking
advisory services
         from Roth for assistance with "defining objectives" and "potential
equity offerings" after
         CLAQ has already selected a target company and negotiated the merger
transaction, the
         CLAQ board approved the transaction, and you entered PIPE equity
financing
         subscription agreements on or about December 14, 2021. Further,
confirm that Nauticus
         is to pay Lake Street after the Business Combination for assistance
Lake Street will be
         provide to evaluate CLAQ's capital raising strategies and investor
relations, among other
         things. Clarify whether you contemplate these services are to assist
the combined
         company after the Business Combination, and, if so, revise so that you
clearly refer to the
         combined, post-Business Combination entity.
9.       Further, we note your assertion in response to comment 9 that the
agreements with Roth
         and Lake Street are not required to be filed under Item 601(b)(10) of
Regulation S-K
         because they only require a contingent cash payment at closing and the
parties have no
         ongoing obligations post-closing. Given that these agreements appear
to be material, were
         not made in the ordinary course of business, and are to be performed
in part at or after the
         filing of the registration statement, please file the letter
agreements as exhibits to the
         registration statement. Alternatively, provide us with a detailed
analysis of why such
         agreements are not material.
If CLAQ's due diligence investigation of Nauticus was inadequate..., page 70

10.      We note your response to prior comment 2. Clarify if CLAQ's management
identified any
         "relevant Nauticus information not considered by CLAQ   s management"
and disclose any
         material information that was identified. We further note that the
CLAQ Board engaged
         the fairness opinion provider after approving the merger. Specify when
and why "the
         CLAQ Board considered that CLAQ may not have properly valued
Nauticus."
 Eli Spiro
FirstName
CleanTech LastNameEli   Spiro
           Acquisition Corp.
Comapany
May        NameCleanTech Acquisition Corp.
     18, 2022
May 18,
Page 4 2022 Page 4
FirstName LastName
Risk Factors
CLAQ and Nauticus have incurred and expect to incur significant costs
associated with the
Business Combination..., page 74

11.      Please revise to reflect the current estimated business combination
related expenses for
         both CLAQ and Nauticus so that they agree with the amounts disclosed
in pro forma
         adjustment (C) on page 182.
Certain Nauticus' Projected Financial Information, page 107

12.      We note your response to prior comment 7 and your revisions on page
108 of your
         disclosure. Advise how the purchase orders that are not "precisely"
through your RaaS
         model have attributes of your RaaS model. In your example of the
18-month lease
         arrangement, clarify whether you provide the labor costs associated
with the operation of
         the Aquanaut or whether this is provided by a third-party.
Customers, page 158

13.      We note your response to prior comment 16. Explain further the
particular customer
         base    to which the Collaboration Agreement provides Nauticus access.
For example,
         clarify, if true, that the agreement provides the company greater
access to contracts with
         U.S. government agencies or other opportunities. We also note that a
copy of the
         Collaboration Agreement was not filed as an exhibit to your
registration statement. As
         previously requested, file a copy of this agreement or tell us why
this is not required.
         Provide a legal analysis that addresses Item 601(b)(10) of Regulation
S-K.
Management's Discussion and Analysis of Financial Condition and Results of
Operations of
Nauticus
Overview, page 162

14.      We note that certain of your disclosure in the Overview section of
Management's
         Discussion and Analysis is a repetition of information included in
your Business
         discussion. Please revise your Overview section to provide a more
tailored and
         streamlined discussion that identifies the most important themes, or
other significant
         matters with which management is concerned, in evaluating the
company's financial
         condition and operating results for the reported periods included in
your financial
         statements. Also, to the extent that there are any material events or
known uncertainties
         that are reasonably likely to cause reported financial information not
to be indicative of
         future operating results or financial condition, please discuss here.
For example, we
         note you are focused on commercializing your products and services and
shifting to a
         RaaS model in the near future. Refer to Item 303(a) of Regulation S-K.
 Eli Spiro
FirstName
CleanTech LastNameEli   Spiro
           Acquisition Corp.
Comapany
May        NameCleanTech Acquisition Corp.
     18, 2022
May 18,
Page 5 2022 Page 5
FirstName LastName
Unaudited Pro Forma Condensed Combined and Consolidated Financial Information
Description of the Business Combination, page 176

15.      We note your revised disclosure and response to prior comment 18. We
also note your
         risk factor disclosure on page 67 regarding the need to hire a CFO
with public company
         experience in order to satisfy the Debt Financing agreement
conditions, and that failure to
         do so would compromise your ability to meet the minimum cash
requirement of $50
         million to close the Business Combination unless that condition is
waived. Please revise
         here to disclose this fact, specifically addressing which party(s) has
the ability to waive
         the minimum cash requirement and the potential likelihood of such a
waiver being
         granted. Also, address here what will happen if the minimum cash
requirement condition
         is not met for any reason, and you are unable to obtain a waiver of
this condition.
Notes to Unaudited Pro Forma Condensed Combined and Consolidated Financial
Information
Note 3. Adjustments to Unaudited Pro Forma Condensed Combined and Consolidated
Financial
Information, page 181

16.      We note your response to prior comment 19 and your revised disclosures
in pro forma
         adjustment (C). Please explain further how you determined that the
$6.0 million payable
         pursuant to the Business Combination Marketing Agreement with Chardan
qualify for
         equity classification. In this regard, we note that such costs include
fees paid for holding
         stockholder meetings to discuss the potential business combination and
the target
         business's attributes and assisting CLAQ in obtaining stockholder
approval for the
         merger. As such, it is unclear how you determined that such costs are
not transaction
         costs to the merger. Refer to SAB Topic 5.A.
Related Party Loans, page 224

17.      We note your written response to prior comment 23 indicating that you
have "revised the
         disclosure on page 225 to disclose its [Chardan Capital Markets,
LLC's] outstanding
         borrowings." However, no changes were made to page 225. Advise if
there are
         outstanding borrowings to disclose and, if so, revise your disclosure
accordingly.
CleanTech Acquisition Corp. Notes to Consolidated Financial Statements
Note 1. Description of Organization and Business Operations, page F-7

18.      We note your revised disclosures and response to prior comment 1.
Please further revise
         here on pages F-10 and F-12 to disclose the exercise price of the
associated warrants.
         Additionally, in your disclosure on page F-12 you state that the
debentures and warrants
         will equal 100% of the amount of the debentures, while elsewhere in
the filing you state
         they will equal 120% of the amount of the debentures. Please revise or
advise. Similar
         revisions should also be made to your disclosure on page 177, as
appropriate.
 Eli Spiro
FirstName
CleanTech LastNameEli   Spiro
           Acquisition Corp.
Comapany
May        NameCleanTech Acquisition Corp.
     18, 2022
May 18,
Page 6 2022 Page 6
FirstName LastName
Note 11. Subsequent Events, page F-27

19.      We note your revised disclosures and response to prior comment 26.
Please tell us
         whether your discussion of the February 28, 2022 agreement with B
Capital Markets
         Advisor is the same as the Lake Street Capital Markets agreement
discussed on page F-47.
         If so, revise here to clarify that while CLAQ contracted for the
advisory services, the non-
         refundable retainer will be paid by Nauticus.
Nauticus Robotics, Inc. Notes to Financial Statements
Note 2. Summary of Significant Accounting Policies
Revenue Recognition, page F-35

20.      We note your revised disclosures in response to prior comment 31 where
you provide a
         breakdown of remaining performance obligations included in contract
liabilities. Please
         tell us whether you have any additional remaining performance
obligations not currently
         included on your balance sheet. If so, revise to disclose or explain
further why you
         believe such disclosure is not necessary. Refer to ASC 606-10-50-13.
21.      We note your revised disclosures and response to prior comment 32.
Please tell us where
         the underlying leased asset (e.g., the Aquanaut) is reflected on your
balance sheet and the
         current carrying value of this asset. Additionally, please provide us
with your analysis
         that supports your conclusion that this arrangement qualifies as an
operating lease under
         ASC 842. In your response, specifically address your consideration of
each of the
         conditions in ASC 842-10-25-2 and 25-3 regarding sales-type and
direct-financing leases.
         Finally, ensure you have disclosed all the information required by ASC
842-30-50, as
         applicable, for the appropriate type of lease agreement.
Exhibits

22.      We note that you have redacted information from portions of exhibits
10.20, 10.21, 10.22,
         10.23, and 10.24. Revise to indicate that this information has been
redacted according to
         the procedures set forth in Item 601(b)(10)(iv) of Regulation S-K.
Mark the exhibit index
         to indicate that portions of the exhibits have been omitted and
include a prominent
         statement on the first page of each redacted exhibit that certain
identified information has
         been excluded from the exhibit because it is both not material and is
the type that you treat
         as private or confidential. Further, revise your proxy
statement/prospectus to clearly
         describe the material terms of each contract, including the term and
termination provision,
         and each contract's date of execution and counterparties, to the
extent not already
         disclosed.
23.      We refer to prior comment 37 from our comment letter dated March 1,
2022. We further
         note your disclosure on page 159 in the section "Material Contracts"
stating that "Nauticus
         has derived significant revenue from its U.S. Department of Defense
related contracts and
         customers" and that the "contracts mentioned herein are included as
Exhibits 10.20, 10.21,
         10.22, and 10.23 to this prospectus." Revise and file the appropriate
exhibit(s) or advise
 Eli Spiro
CleanTech Acquisition Corp.
May 18, 2022
Page 7
      as to which exhibit details your arrangement with your significant
customer (which
      accounted for 89% of Nauticus' total revenue in 2021 according to your
risk factor
      disclosure on page 43).
24.   We note your disclosure that Nauticus signed an agreement with Kongsberg
Maritime AS
      for two Launch and Recovery Systems. Advise how Nauticus will use these
systems and
      file a copy of this agreement or advise why this is not required. In
general, update your
      proxy statement/prospectus to reflect any updated business plans and the
status of any
      publicly announced new product or service. In that regard, we refer to
Nauticus' recently
      announced strategic relationship with Wood PLC and intention to launch a
"robotic navy"
      of 20 Hydronaut-Aquanaut "tandem pairs" by the end of 2024 together with
your plan for
      regional operation centers in the Gulf of Mexico, Norway, the United
Kingdom, and
      Brazil. Refer to Item 101(h)(4) of Regulation S-K.
       You may contact Brittany Ebbertt, Senior Staff Accountant, at (202)
551-3572 or
Kathleen Collins, Accounting Branch Chief, at (202) 551-3499 if you have
questions regarding
comments on the financial statements and related matters. Please contact
Patrick Faller, Staff
Attorney, at (202) 551-4438 or Joshua Shainess, Legal Branch Chief, at (202)
551-7951 with any
other questions.



                                                          Sincerely,
FirstName LastNameEli Spiro
                                                          Division of
Corporation Finance
Comapany NameCleanTech Acquisition Corp.
                                                          Office of Technology
May 18, 2022 Page 7
cc:       Giovanni Caruso
FirstName LastName