building a pocket trawler from an S2 8.0 C

Discussion in 'Boat Design' started by popeyejackusn, Jun 3, 2019.

  1. popeyejackusn
    Joined: Jun 2019
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    Location: deland Florida

    popeyejackusn New Member

    I've just purchased an S2 26 ft center cockpit sailboat. I believe I can make a trawler from it. It is full displacement, 30 inch draft, with a Yanmar diesel. It weighs 5,000 lbs and is trailerable. I just wonder if anyone has heard of anyone building one from that same boat design.
     
  2. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    I am guessing that yours is the 8.0 C model, as per the link below?
    SailboatData.com - S2 8.0 C Sailboat https://sailboatdata.com/sailboat/s2-80-c

    Re 'making a trawler from it', what is your proposed plan?
    Are you thinking of building a wheelhouse over the cockpit area?
    Does it still have a sailing rig?
    Are you going to keep the Yanmar diesel that is currently installed?
    Is it the 8 hp YSM 8 as mentioned in the link below?
    Specifications of S2 8.0c Coming About ~ s/v Coming About https://s2-coming-about.blogspot.com/p/specifications.html
    You could put a bigger engine in (if desired), perhaps up to 25 - 30 hp at the most, but there is no point in going any bigger than this really.
     
  3. popeyejackusn
    Joined: Jun 2019
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    Location: deland Florida

    popeyejackusn New Member

    Yes, it is the 8.0 C model. I'll most likely pull the current motor YSB 8 and install a 2 GMF. Increase the fuel and water capacities. Install more ports and windows along the front of the raised cockpit. Build a hardtop from the front of the cockpit to the end of the stern. Not sure of enclosing it. It has no mast or rigging.
     
  4. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    That should turn out to be a very nice little trawler yacht.
    And with only 30" of draft, you shouldn't have to worry too much about her being 'too stiff' (re rolling) without the sailing rig.
    Re installing a 2GM engine instead of the YSB8 - this will be twice the power, so you might well have to change the propeller, depending on what the gearbox ratio is on the new engine when compared to the old engine.
    Here is some general info about the 2GM.
    Yanmar 2GM20 - Wikipedia https://en.wikipedia.org/wiki/Yanmar_2GM20
    And she should be VERY economical on fuel - at least 10 miles per gallon, probably more (15 even?).
     
  5. goodwilltoall
    Joined: Jul 2010
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    Location: nation of Ohio

    goodwilltoall Senior Member

    Saildata shows 4' draft, is it a CB boat?
    Its a small, light, displacement boat and the current engine probably gives her all the power she can use, it would be a lot of work/costs for small improvement plus take up valuable room
     
  6. goodwilltoall
    Joined: Jul 2010
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    Location: nation of Ohio

    goodwilltoall Senior Member

    Nice layout, I would concentrate on new deck and pilot house design, so many conversions ive seen turn into frankenboats
     
  7. goodwilltoall
    Joined: Jul 2010
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    Location: nation of Ohio

    goodwilltoall Senior Member

    Allweather boats, same dimensions as yours
     

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  8. Milehog
    Joined: Aug 2006
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    Location: NW

    Milehog Clever Quip

    I'd try to catch a ride on another converted sailboat. I've heard they will roll your guts out.
     

  9. Phil_B
    Joined: Mar 2019
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    Location: New Zealand

    Phil_B Junior Member

    True - the mast acts as a roll damper as it has its centre of mass a long way from the roll axis.

    Tony Marchaj describes this phenomenon in his book "Seaworthiness - the Forgotten Factor" where he tested a model yacht in a wave tank and found that, contrary to the expected result, the model yacht without the mast was repeatedly rolled but the same hull with the mast was not rolled in the same wave conditions.

    Seek the advice of a naval architect about redistributing the ballast and/or restoring the roll inertia of the hull without the mast and even if it is possible.
     
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