building pontoon logs

Discussion in 'Boat Design' started by lil beaver, Sep 20, 2015.

  1. lil beaver
    Joined: Sep 2015
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    Location: lancaster, pa

    lil beaver New Member

    Hello all,

    I have an older 20' pontoon that we use for crabbing and fishing in the Chesapeake bay. It is in rough condition, and the saltwater has taken it's tole on the logs over the years. I have been thinking about building new glass over wood logs for it as well as a new pod for my outboard. Glass will hold up better to salt, and hopefully if designed right give me more speed.

    I have put together a rough design for this and wanted to get your opinion. Let me just clarify that I am no designer and have no experience designing anything. Any and all input is welcomed. The logs are 22" high, around 26" wide at water line, with a 10 degrees deadrise. A increase in flotation, and running surface from my 23" round aluminum logs I have now.

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  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    Looks good. Depending on the conditions you go out in, a finer entry bow could help. The Chesapeake gets a nasty chop at times.
     
  3. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    Lil Beaver, be particularly wary, the phrase "looks good" could be the beginning of your downfall. You should ask someone knowledgeable to do some brief calculations to check that the pontoon, in all cases, will behave as you wish.
     
  4. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    Looks much gooderer than round ones... depending on power and speed some spray rails/deflecters might be good too, looks a lot like a pontoon boat built by a Quintrex worker that I saw, seemed to go good with from distant memory about a 20-25hp outboard.
    I think some steps for entry/egress from water might be nice too.... twin outboards would get rid of the centre pod/nacelle but at extra cost ...., some extra sharp V to the nacelle would be good too.....
    Jeff
     
  5. lil beaver
    Joined: Sep 2015
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    Location: lancaster, pa

    lil beaver New Member

    I should have added what motor I would like to use. The toon as it sits has a '89 Johnson 90 on it. It is tired. I have a 1981 manatee 21' vbr with a 2014 175 mercury optimax pro xs on it. It has 39 hours on it. The manatee has just sat mainly because the family prefers the toon. Fishing, crabbing, or just hanging out, the old ugly toon is the one that is requested. It may be time to sell the manatee and upgrade the toon.
     
  6. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    Presumably you aren't going out into big chop with that, based purely on the low bows, but it might help as gonzo says to be a little less blunt forward. And it could get pretty wet too.
     
  7. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Spray rails can help keep the deck dry too.
     
  8. lil beaver
    Joined: Sep 2015
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    Location: lancaster, pa

    lil beaver New Member

    yup, fair weather boaters we are. I will have to add spray rails, but that will come after I see exactly where they are needed. Removing the blunt front on the toons is another option. Not sure if it will be needed. I anticipate the bow ridding fairly high with the big motor on the back. I'm more concerned that I may have to add a center flotation pod to offset the 450lbs hanging 14 inches off the back of the toon.
     

  9. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Welcome to the forum.

    I agree with Gonzo and TANSL. First the entry could and likely should be finer. I grew up on the Chesapeake and well know it's behavior. Second to TANSL's point, just because it "looks" good, doesn't mean it do anything the way you'd like. You know simple stuff, like float where you think it should, ,maybe hold up all you gear, crew and building materials, remain upright if everyone runs to the same rail, etc. 'Glass over plywood plans for pontoons are available and you'd be wise to invest in a set of them.
     
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