What is the formula for sail size to hull for junk rig?

Discussion in 'Motorsailers' started by Andrewski, Mar 4, 2020.

  1. Andrewski
    Joined: Mar 2020
    Posts: 3
    Likes: 0, Points: 1
    Location: Sydney

    Andrewski New Member

    I am thinking of buying a motor sailer, but its sails are pretty small. (I think)
    The hull is a Roberts 43 extended to 48, custom pilot house etc, with junk rig on 12 meter poles.
    To me the sails look too small, but i need some sort of formula. How many sq ft of sail does a 48’ need. Its got 2 masts.
    Many thanks
    Andrew
     

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  2. bajansailor
    Joined: Oct 2007
    Posts: 647
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    Location: Barbados

    bajansailor Marine Surveyor

  3. Rumars
    Joined: Mar 2013
    Posts: 421
    Likes: 128, Points: 43, Legacy Rep: 39
    Location: Germany

    Rumars Senior Member

    There is no answer to your question. A sailboat gets the sail area the designer calculates the boat can stand up to. After the mods done to that boat not even Roberts himself can tell you the appropiate sail area without recalculating the entire boat. That said the Roberts 43 did not had an overly generous sail plan to begin with. Bruce Roberts, steel boat plans, boat building, boatbuilding, steel boat kits, boat kits https://www.bruceroberts.com/public/HTML/descriptions/Roberts43_description.htm
     
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  4. bajansailor
    Joined: Oct 2007
    Posts: 647
    Likes: 159, Points: 43, Legacy Rep: 37
    Location: Barbados

    bajansailor Marine Surveyor

    Andrew, re how you are thinking of buying this boat, what do you find appealing about it?
    Is it perhaps a combination of price and amount of accommodation available?
    The photo does suggest that she has been extensively modified from the 'standard' Roberts 43 - and rather than looking to increase the sail area you would probably be better off looking for another boat that meets your requirements.
    Does it HAVE to have a junk rig?
     
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