Need advice on building cheap pontoons

Discussion in 'Wooden Boat Building and Restoration' started by MarkIFC, Nov 14, 2007.

  1. MarkIFC
    Joined: Jul 2007
    Posts: 12
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Ohio

    MarkIFC Junior Member

    My pontoon style houseboat has about a 5 foot overhang in the rear. The weight causes the stern to hang low. The previous owner strapped (literally with nylon tiedown straps) on old plastic dock floats. I want to redo it better by fabricating some auxillary pontoons.

    A couple of notes, the boat is on an inland lake. The 50 hp motor pushes the boat at maybe 10 mph tops so it doesn't plane. These are auxillaries meant to last 5 to 10 years. If they start to leak the boat won't sink. They don't have to look pretty. I'm just looking for an alternative to the rusty 55 gal. drums everyone else uses for the same purpose.

    My idea was to build the pontoons out of 3/4 plywood held together with PL Premium Polyurethane glue and stainless screws and then paint them.
    Questions:
    Should I use pressure treated plywood or will CDX work just fine? Using 3/4 plywood I can't justify marine plywood. If I use CDX do I need to coat the seams with epoxy resin and fiberglass tape or can I just paint it? The interior too? Is it necessary to cloth the entire surface?

    I tried to attach a drawing of what I have in mind.
     

    Attached Files:

  2. rwatson
    Joined: Aug 2007
    Posts: 5,866
    Likes: 299, Points: 83, Legacy Rep: 1749
    Location: Tasmania,Australia

    rwatson Senior Member

    Gut feel - sounds fair enough with exterior grade plywood.
    I am not sure of what CDX is, I presume "particleboard", which I think would be lucky to last 2 years in constant immersion.
    If you cost the option of epoxy and cloth on the sides and bottom, versus just paint, you might find it might increase the cost by 10%, but increase longevity by 100%, especially if you allow for the occassional minor impact over the years. Dont forget you will use a less paint with epoxy.
    The big unknown is the quality of the plywood you get hold of. I would certainly at leat paint the inside.
     
  3. NauticalLumber
    Joined: Nov 2007
    Posts: 9
    Likes: 0, Points: 0, Legacy Rep: 2
    Location: warren, michigan

    NauticalLumber Nautical Lumber Co.

    I have some pretty nice structual marine plywood 3/4" x 4' x 8' for $69.50 if that helps. For the cost difference...which shouldn't be much. You'll get a much longer life out of your project.
    Let me know if i can be of any help.
    Regards,
     
Loading...
Similar Threads
  1. grjack
    Replies:
    4
    Views:
    1,470
  2. manos mit
    Replies:
    21
    Views:
    4,796
  3. JonRiley56
    Replies:
    1
    Views:
    1,513
  4. highace10
    Replies:
    12
    Views:
    4,142
  5. spears
    Replies:
    1
    Views:
    1,851
  6. longfellow
    Replies:
    7
    Views:
    1,373
  7. Wooscot31
    Replies:
    24
    Views:
    14,669
  8. rideaubill
    Replies:
    17
    Views:
    3,174
  9. nitromike02
    Replies:
    13
    Views:
    1,626
  10. andremh
    Replies:
    4
    Views:
    1,684
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.