Transom Extension

Discussion in 'Sailboats' started by Dynamite Jeff, Nov 11, 2014.

  1. Dynamite Jeff
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    Dynamite Jeff Junior Member

    BTW, just to answer question, it is 1975 Doug Peterson 2 Ton. I do not know where she was made.
     
  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Is this the boat?

    [​IMG]

    Are you sure it's a 1975 Peterson, as I'm unaware of any 40'ers he did that year. He did a production version of GumBoots (below), but this was about 35'.

    [​IMG]
     
  3. CT249
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    CT249 Senior Member

    there were some '75 Peterson 2 tonners. Peterson's Ricochet won the '75 Two Ton Cup on the Great Lakes. Another '75 Peterson 2 ton was Natelle II, built in NZ for the 1975 Southern Cross Cup team but soon sold to Oz where she did well. I seem to recall that California's Vendetta was also a '75 boat. These tended to have the more upright transom of the OP's boat whereas I think the '76/77 Petersons had more rake. I don't know the LOA (I'd probably have it buried somewhere in the magazine collection in my garage) but they were quite short for two tonners.
     
  4. PAR
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    PAR Yacht Designer/Builder

    Yep, that's what I remember, but the OP said it was a 40' boat, which would be a pretty narrow thing for a mid 70's Peterson IOR 2 ton.
     
  5. Dynamite Jeff
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    Dynamite Jeff Junior Member

    It was called Dogpatch originally out of San Fran and I am pretty sure about the year and designer.

    I think that picture is a New York 40 and honestly the hull looks similar to me. She has a flush deck though and winches everywhere!, 0 (zero) exterior portholes and the PO said she used to have a deep cockpit, right now it is about a foot deep. I love how she is so "all business".

    Also now I am looking at it, the transom is more upright and the engine is much further forward than in the first picture.
     
    Last edited: Nov 15, 2014
  6. Dynamite Jeff
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    Dynamite Jeff Junior Member

    Definitely 40' - thats what the marina is charging me for :(
     
  7. Islander Murray
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    Islander Murray New Member

    Morgan sugar scoop

    I have a 1976 Heritage West Indies 36 made by Charlie Morgan (2nd company). He took a couple of these and designed a sugar scoop (around 1983-4)which mine has. Bumps them out to 39 ft. My limited research tells me that the best types to convert or add is when the design has a fuller beam carried further aft. Is is best if there is not a lot of over hand to the existing transom design, almost flush or actually submerged. The addition definitely increase water line to length ratio. I love the feature and may have passed on the boat if it had not been there. Islander Murray
     

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  8. Ja guar
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    Ja guar Junior Member

    IM is right.

    Shoot the Moon is one of Peterson's earlier pin-tail designs - much like the first Peterson Cadenza (shown below) and not really a good candidate for an extension.

    As IM mentioned, extensions work by increasing sailing length, mainly through lengthening the immersed volume distribution (for lack of a better term).

    Extensions were done to later IOR boats, mainly for IMS purposes, but later IOR boats had wider sterns, shallower buttock lines and minimal if any bustle. So it was fairly easy to make an extension to lengthen immersed volume.

    One of the problems with a pin-tail is that with the narrow stern beam, steep buttock lines, and rapidly narrowing immersed volume, you simply run out of real estate to make much of an extension - unless you start making reverse curves.

    Having said that, it could be done, but you would have to cut out roughly the back third of the boat in order to create a shape with reasonably greater sailing length.

    A similar concept applies to boats where owners want to replace a raked stem with a plumb bow - it usually doesn't work well unless done properly (starting at station 4), which gets expensive.

    Cadenza photo courtesy of Pastperfect.
     

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  9. Dynamite Jeff
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    Dynamite Jeff Junior Member

    Thanks Jaguar. I guess I'll just build the Cousteau-style observation dome and call it good then :(
     
  10. Canracer
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    Canracer Senior Member

    Good God, don't touch that boat. It's awesome just the way it is. Although, a Cousteau-style observation pod is genius level thinking. :D

    [​IMG]
     

  11. wjmuseler
    Joined: Feb 2016
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    wjmuseler Junior Member

    Murray,
    That is my old boat! I believe that four boats had that modification. It definitely smooths out quarter wake.

    Will Museler
    westindies36.com
    Heritage West Indies 36 'Mystere' Hull #1
     
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