12.5 foot drift boat, plascore, 17oz biax

Discussion in 'Fiberglass and Composite Boat Building' started by Deadrift, May 10, 2017.

  1. Deadrift
    Joined: May 2017
    Posts: 3
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    Location: SE Detroit

    Deadrift New Member

    Hello everyone! First post. Lots of great info here. Curious about the forces exerted on a drift boat, specifically on water in the Midwest. Generally class one water, rarely class two.

    Curious where the most stress is exerted on a low sided small drift boat?

    So far 3-4 layers of 17 oz biaxial on the outside of 1/2" plascore, but the boat still isn't stiff. Need to glass the inside, add the gunnel and I'm sure it'll stiffen up. Just curious what the layup of the inside should be.

    Will be working with 17 and 14 Oz biaxial for the inside (on sale from Raka).

    Also, what's the safest way to flip the boat off the frames, what do I need to be careful of??

    Thank you for any help!
     
  2. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    You should try to make the outer and inner laminates as similar as possible, so that the distribution of stresses in the thickness is symmetrical with respect to the neutral axis.
     
  3. Deadrift
    Joined: May 2017
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    Location: SE Detroit

    Deadrift New Member

    Thank you! Here she is so far.

    boatresize.jpg
     
  4. Ike
    Joined: Apr 2006
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    Location: Washington

    Ike Senior Member

    That's a very small drift boat! I hope you are only planning to use it on smooth water. (I know, you said class 1 or 2)
     
  5. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    If there are rocks, the chines take the most abuse, so most drift boat builders add a great deal more glass to them.

    As mentioned, the skins on each side of the core should be similar, but sometimes if the outer skin is subject to significant abrasion it may be thicker.

    Depending on the style of gunnel you add it will increase the stiffness a great deal.

    The hull sides don't need to be very thick.
     
  6. jorgepease
    Joined: Feb 2012
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    Location: Florida

    jorgepease Senior Member

    That should be pretty easy to flip with a couple friends, if you do it yourself, put it in a sling, front and back, hoist it up a few feet and spin it. If you're scared of the sides folding in you can brace them with a temp structure. Are there no benches you can glass in while you have it right side up?
     
  7. Deadrift
    Joined: May 2017
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    Location: SE Detroit

    Deadrift New Member

    Thanks everyone, the outside chine is 6-8 layers of 17 oz biaxial glass, yes very calm water, going to do a laminated white oak gunnel.

    How hard is it going to be to get UHMW to bend? Ordered a block to make oar locks blocks
     
  8. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    I used UHMW for oarlocks on the boats I made, Mine was a thick sheet, so bending wasn't an option, the pieces were bolted in place and several holes were drilled to receive the oarlock. This was so they could be adjusted as needed. The block was 1.5" thick 8" long and tall enough so the oarlock had just enough room for the clip on the bottom of the shaft to be put in place, it was bolted in place under the rolled gunnel.

    You can form thinner sheets of UHMW with a heat gun, heat lamp or oven, warm gently.
     
  9. Barry
    Joined: Mar 2002
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    Barry Senior Member

    A better lasting plastic is a graphite impregnated polyethylene, less deformation of the oar lock pin to bore of the plastic over time.
    This was our go to plastic for manual boat davits rated to 800 lbs
     
  10. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    I haven't used the graphite impregnated product, I have a about 25 years on the oldest set, only about 10 years of the that was hard use though, so far the bore looks about the same as new, the outside has aged and cracked a bit though.
     

  11. Tungsten
    Joined: Nov 2011
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    Location: Canada

    Tungsten Senior Member

    2 layers for the floor and one for the sides should be enough for the inside this will stiffen the boat.Any more and you'll end up quite heavy for a small boat. If attaching wooden gunnels you'll want to drill out some attach points in the core so you can use screws,fill these with a dense filler and epoxy then glass over.
     
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