design on shallow draft craft.

Discussion in 'Boat Design' started by jtmboat, Mar 4, 2009.

  1. jtmboat
    Joined: Feb 2009
    Posts: 7
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Raleigh, NC

    jtmboat Junior Member

    Cross posting this from the construction forum, not sure which forum would be best to assist.
    I'm wanting to build a very shallow drafting craft that will have a bow mounted trolling motor to use when in deep enough water and poled in xtreme shallows in marshes. I want very low flat deck to stay out of the wind as much as possible and thinking along the lines of a large 'stand-up paddle board' design. Only going to support one person a trolling motor and a cooler to house the battery for the trolling motor and light fishing gear.
    Probably 12' in length, 4'-5' beam and 6"-7" thickness. Just a long rectangular "box" with flat deck , sides and bottom and bringing the bottom up in a taper to a 2" nose thickness starting the taper about 24" from the bow. I was basing diminsions on the 5' x 12' having 5 cubic feet of floatation for every inch submerged, thus able to float roughly 300lbs. for every inch submerged if weight on boat was evenly spread out. That should be perfect.
    I was originally thinking using 2" thick x 6" tall x 12' lengths of foam sandwitched and strengthened with 1/8" marine ply every 4" of foam width.
    If i went this route, could i just glass the entire hull or would i need a ply deck to keep from compressing the foam or would glassing be strong enough to begin with? If so, what weight cloth could i use to get away with it being strong enough to walk about on?
    If this would take too much glass(ie. heavy) would a stitch and glue built hull be better/lighter?
    Never having made a boat before, much less stitch and glue style,,,what thickness ply should i use and how many stringers or bulkheads and how much spacing is needed to support a deck(and what thickness should the deck ply be). And then do you glass and epoxy, or just epoxy the end result? If glass is needed , what weight cloth(s)?
    I hope i've described the setup and my concerns properly to give you folks enough to respond.
    I'm hoping to build the lightest craft possible and still have a strong enough craft to stand on w/out concerns of buckling.

    Thanks in advance for any/all assistance you can provide.
  2. Village_Idiot
    Joined: Oct 2007
    Posts: 382
    Likes: 15, Points: 18, Legacy Rep: 138
    Location: USA

    Village_Idiot Senior Member

    First off, I don't know anything about laying up fiberglass, so I prolly can't help other than to throw some ideas out there...

    Check out the Texas Scooter boats that they use down on the coastal flats. These boats are typically 8' - 12' long, four feet wide and six inches thick, but made from anything from wood to 'glass to aluminum. Most of them have large center consoles and 40-60hp outboard engines, with just enough room for one or two people to fish from.

    Don't know how strong just 'glassed foam will be. I think even a very thin sheet of plywood would greatly increase your puncture resistance and add very little weight. Maybe think about formica or some type of thin plastic reinforcement board, like what the panels in your bathroom shower are made of.
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.