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Hidden Sponsons

Discussion in 'Wood and Canvas' started by DavidK, Feb 21, 2021.

  1. DavidK

    DavidK Curious about Wooden Canoes

    In reference to what I know believe is a Skowhegan Pathfinder, I'm looking for guidance on how the sponsons get covered. I think Old Town canvased their boat and then added the sponsons (and then covered them) right? On this boat, the fragment I have left of the old transom shows the canvass going over the sponson. Looks like a light weight fabric under the sponson.
  2. OP

    DavidK Curious about Wooden Canoes

    Found this fabric that had been removed from the boat. Looks like it was tacked on the side before the sponson was mounted.
  3. OP

    DavidK Curious about Wooden Canoes

    Spent some time piecing together the starboard sponson. The aft end of the boat had been sawed off. Luckily, the prior owner saved the pieces.
    IMG_4624.JPG IMG_4623.JPG IMG_4622.JPG IMG_4620.JPG IMG_4625.JPG
  4. Rollin Thurlow

    Rollin Thurlow member since 1980

    Well, you do have a challenge ahead of you!
    Basically it is something like this,
    1) Remove sponsons. Repair the boat and the sponsons as needed.
    2) stretch canvas over the area where the sponsons were. Fill the canvas.
    3) Reattach the sponsons. the last plank on the sponsons is tapered to a feather edge so the sponsons planking will flow smoothly into the hull of the canoe.
    4) Trim the bottom canvas so it is not exposed. On the top, leave enough canvas so it can be folded or rolled over the top the sponsons.
    5) Canvas the whole boat. The top edge of the canvas will be attached to the top edge of the sponsons (not at the canoes rail).
    6) fold the top edge of the canvas that is sticking out from behind the sponsons and fold it over the top edge of the sponsons so that it coverers the top edge of the canoe hull canvas.
    7) A outside "trim rail" or "sponson cap" will cover the canvas lap..
    8) Sand, paint, sand paint sand paint, varnish, sand ,varnish, paint and varnish again and your all done!

    Picture 115- canvasing under the sponson area.
    picture 118 - installing the invisible sponson. The last plank on the sponson is feathered to be smooth with the hull. the excess canvas will be trimmed to the feather edge.
    Picture 131 - the sponson canvas is rolled over the top of the sponson. The outside hull canvas is trimmed to the top of the sponson. In the picture you can see the canvas lap on the edge of the sponson.
    picture 134 - Applying the trim rail that covers the canvas lap.
    Picture 141 - the finished boat.

    There are different variations of canvasing inviable sponsons but they all require the sponsons to be removed, canvas put underneath, reattach the sponsons and then recanvas the whole ball of wax!

    Attached Files:

    MGC likes this.
  5. OP

    DavidK Curious about Wooden Canoes

    Hi Rollin. Thank you, so much, for your guidance! I have ordered a copy of your book. Very cool to get a response from you directly.

    Your technique looks like it would seal the sponsons better than the original. The fabric I show above is thin, not canvas. It may have been treated with some water repellent? Clearly you'd want to keep water out of there

    What do you call the shaped support pieces for the sponson? Ribs?
    Screen Shot 2021-02-21 at 7.44.55 PM.png
  6. Rollin Thurlow

    Rollin Thurlow member since 1980

    I think sponson stations or frames be about right.

    Attached Files:

  7. Gil Cramer

    Gil Cramer The wooden canoe Shop, Inc.

    Rollin, excellent concise directions.
  8. OP

    DavidK Curious about Wooden Canoes

    Great directions, and the photos are so very helpful!
  9. chris pearson

    chris pearson Michigan Canoe Nut

    I told ya Rollin was the expert!!!!!

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