split: rebuilding stingers for a foam cored hull

Discussion in 'Fiberglass and Composite Boat Building' started by ride2unwind, Oct 6, 2010.

  1. ride2unwind
    Joined: Oct 2010
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Florida

    ride2unwind New Member

    This actually has nothing to do with wooden thingamajigs, but I was hoping someone could answer a few questions for me on rebuilding stingers for a foam cored hull. I have recently started work on a 1976 Bayliner "Liberty" only to come across runs runs of waterlogged decking and stringers. So far I have removed the deck , all exposed stringers , the 40gal fuel tank , and the cabinets in the cabin. My questions are : Do I need to remove all the foam core that is left all over ? Should I still rebuild the stringers from marine grade 3/4 " ply wood ? Is there a way to patch an alluminum tank with some pin holes and varnish inside ? If rebuilding with plywood , how do you achieve the length of a 12' stringer when the lumber store only carries it in 8' length and maintain strength?
  2. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 475, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Ride2unwind, there are many threads (previous posts) which will address most of your concerns. The search tool and an evening of "catching up" on the various subjects can be especially helpful to you.

    This said, the era of your boat suggests it was foamed with a open cell material which absorbs moisture. I've disassembled boats with several hundreds of gallons of water stored in the damn foam. Also gas, oil, mold, mildew, fish spit and other bodily functions, diesel, you name it. Naturally, this "stored" moisture also tends to rot out all the stringers, sole supports, braces, soles, etc. The best thing you can do is ax the foam. It's actually kind of fun if you can still think about your ex-wife and not end up in jail afterward. It cuts very easily and my usual tools are a big, long, flexible, hand saw. Just hack it out the best you can, a grinder after the bulk is gone makes quick work of it.

    Yes, you can patch your tank with a few types of adhesives and a few different internal coating too, but these generally don't prevent a major pin hole from returning.

    You can use solid wood for the stringers if it helps you, but using a "sandwich" of plywood, instead of a single length will work best in lengthening it. Lets say you need 12' of 3/4" stringer. You could scarf some 3/4" plywood at 8:1 or you could use a sandwich of 3/8" glued together with highly staggered seams. This is actually a far bit stronger too, though costs a little more.

    These and other "insights" will appear with a trip down memory lane in our archived previous posts. Yep, it's a bit of weed pulling to find the stuff you need, but it's cheap and we talk about each others wives too.
  3. ride2unwind
    Joined: Oct 2010
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Florida

    ride2unwind New Member

    Thank you for insight and prompt response. Plan to have this all ready by spring so any advice is a great help. I will continue to search the forum for more details. Have a great one!

    “A lot of people ask me if I were shipwrecked, and could only have one book, what would it be? I always say 'How to Build a Boat”

    Stephen Wright
  4. GG
    Joined: Jan 2008
    Posts: 190
    Likes: 4, Points: 0, Legacy Rep: -30
    Location: MICH

    GG offshore artie

    Hey guy , while you got the tank out i would suggest having it professionally repaired , steam cleaned , and pressure tested after the repairs are done and i usally take my tanks to a place that does this type of work because they will warrenty there work which should not cost that much and par has mostly covered everything else .

  5. mark775

    mark775 Guest

    Re: the tanks - I have my doubts that they are thick enuf material with which to bother. these high volume guys build for a finite lifespan and if you have 1 pinhole, you probably have more. Specifically study fuel tank mounting on this site. This is a good opportunity to make the boat a better boat than it was new.
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.