Exhibit 4.1

   

  SPECIMEN UNIT CERTIFICATE

   

  NUMBER UNITS

  U-

   

  SEE REVERSE FOR CERTAIN 

  DEFINITIONS

   

  CUSIP [ ]

   

  BLUE OCEAN ACQUISITION CORP

   

  UNITS CONSISTING OF ONE CLASS A ORDINARY SHARE AND ONE-HALF OF ONE 

        REDEEMABLE WARRANT TO PURCHASE ONE CLASS A ORDINARY SHARE

   

  THIS CERTIFIES THAT                 is the owner of
                      Units.

   

  Each Unit (“Unit”) consists of one Class A ordinary share, par value $0.0001 per share
      (“Ordinary Shares”), of Blue Ocean Acquisition Corp, a Cayman Islands exempted company (the “Company”), and one-half of one redeemable warrant (each whole warrant, a “Warrant”). Each Warrant entitles the holder to purchase one Ordinary Share for
      $11.50 per share (subject to adjustment). Each Warrant will become exercisable on the later of (i) 30 days after the Company’s completion of a merger, share exchange, asset acquisition, share purchase, reorganization or other similar business
      combination with one or more businesses (each, a “Business Combination”), and (ii) 12 months from the closing of the Company’s initial public offering, and will expire unless exercised before 5:00 p.m., New York City Time, on the date that is five
      years after the date on which the Company completes its initial Business Combination, or earlier upon redemption or liquidation (the “Expiration Date”). The Ordinary Shares and Warrants comprising the Units represented by this certificate are not
      transferable separately prior to           , 2021, unless Needham & Company, LLC elects to allow earlier separate trading, subject to the Company’s filing with the Securities and Exchange Commission of a Current Report on Form 8-K containing an
      audited balance sheet reflecting the Company’s receipt of the gross proceeds of the initial public offering and issuing a press release announcing when separate trading will begin. No fractional warrants will be issued upon separation of the Units
      and only whole warrants are exercisable. The terms of the Warrants are governed by a Warrant Agreement, dated as of           , 2021, between the Company and Continental Stock Transfer & Trust Company, as Warrant Agent, and are subject to the
      terms and provisions contained therein, all of which terms and provisions the holder of this certificate consents to by acceptance hereof. Copies of the Warrant Agreement are on file at the office of the Warrant Agent at 1 State Street, 30th Floor,
      New York, New York 10004, and are available to any Warrant holder on written request and without cost.

   

  Upon the consummation of the Business Combination, the Units represented by this certificate
      will automatically separate into the Class A Ordinary Shares and Warrants comprising such Units.

   

  This certificate is not valid unless countersigned by the Transfer Agent and Registrar of
      the Company.

   

  This certificate shall be governed by and construed in accordance with the internal laws of
      the State of New York.

   

  Witness the facsimile signatures of its duly authorized officers.

   

  	By:	 	 	 	 
	 	Chairman	 	Chief Executive Officer	 
	 	 	 	 	 
	 	 	 	 	 
	 	Chief Financial Officer	 	 	 


  
     

    
      
 

  

   

  BLUE OCEAN ACQUISITION CORP

   

  The Company will furnish without charge to each unitholder who so requests, a statement of
      the powers, designations, preferences and relative, participating, optional or other special rights of each class of shares or series thereof of the Company and the qualifications, limitations or restrictions of such preferences and/or rights.

   

  The following abbreviations, when used in the inscription on the face of this certificate,
      shall be construed as though they were written out in full according to applicable laws or regulations:

   

  	TEN COM	—	as tenants in common	 	UNIF GIFT MIN ACT	—	 	Custodian	 
	 	 	 	 	 	 	(Cust)	 	(Minor)
	 	 	 	 	 	 	 
	TEN ENT	—	as tenants by the entireties	 	 	 	under Uniform Gifts to Minors Act
	 	 	 	 	 	 	 
	 	 	 	 	 	 	(State)
	 	 	 	 	 	 	 
	JT TEN	—	
          as joint tenants with right of

          survivorship and not as tenants in

          common

        	 	 	 	 


   

  Additional abbreviations may also be used though not in the above list.

   

  For value received, ___________________________ hereby sells, assigns and transfers unto 

   

  

  
  
     

  

  
  

  PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE 

   

    

  (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)

   

  ____________________ Units represented by the within Certificate, and hereby irrevocably
      constitutes and appoints Attorney to transfer said Units on the books of the within named Company with full power of substitution in the premises.

   

  	Dated	 	 	 
	 	 	 	
          Shareholder

          Notice:      The signature to this assignment
              must correspond with the name as written upon the face of the certificate in every particular, without alteration or enlargement or any change whatever.

        


   

  	Signature(s) Guaranteed:	 
	 	 
	 	 
	
          THE SIGNATURE(S) MUST BE GUARANTEED BY

          AN ELIGIBLE GUARANTOR INSTITUTION

          (BANKS, STOCKBROKERS, SAVINGS AND LOAN

          ASSOCIATIONS AND CREDIT UNIONS WITH

          MEMBERSHIP IN AN APPROVED SIGNATURE

          GUARANTEE MEDALLION PROGRAM, PURSUANT

          TO S.E.C. RULE 17Ad-15 OR ANY SUCCESSOR

          RULES).

        	 


   

  In each case, as more fully described in the Company’s final prospectus dated           ,
      2021, the holder(s) of this certificate shall be entitled to receive a pro-rata portion of certain funds held in the trust account established in connection with the Company’s initial public offering only in the event that (i) the Company redeems the
      Ordinary Shares sold in its initial public offering and liquidates because it does not consummate an initial business combination within the period of time set forth in the Company’s amended and restated memorandum and articles of association, as the
      same may be amended from time to time, (ii) the Company redeems the Ordinary Shares sold in its initial public offering in connection with a shareholder vote to amend the Company’s amended and restated memorandum and articles of association that
      would affect the substance or timing of the Company’s obligation to provide for the redemption of Class A ordinary shares in connection with an initial business combination or to redeem 100% of the Ordinary Shares if it does not consummate an initial
      business combination within the time period set forth therein, or (iii) if the holder(s) seek(s) to redeem for cash his, her or its respective Ordinary Shares in connection with a tender offer (or proxy solicitation, solely in the event the Company
      seeks shareholder approval of the proposed initial business combination) setting forth the details of a proposed initial business combination. In no other circumstances shall the holder(s) have any right or interest of any kind in or to the trust
      account.