extreme light plywood Kayak ????

Roy222

Paddler
Joined
Jun 2, 2009
Messages
387
Have any builders out there built a super light stitch and glue Kayak?
I am thinking :
4 mm thick plywood - 6 or 4 panel design
Fiberglass only the bottom & inside where you sit with 4 oz. glass
Fiberglass the seal ring around the cockpit opening
Seal the seams with thickened epoxy and glass the outside of the seams with bias cut 4 oz. glass
Use paint to seal the rest of the boat
Use a foam seat
Maybe foam bulkheads or that hollow core plastic used to make lawn signs — even folding kayaks
Over lapped hatches sealed with foam — no extra seal ring in hull


The boat would only be used for flat water and near shore

Is 20 pounds possible with a 16 foot long boat?

Roy
 

mick_allen

Paddler & Moderator
Joined
May 15, 2005
Messages
3,168
I think Mac50L does something similar, but maybe with 3mm ply. Look back at some of his old posts and read the approach he uses. I believe he gets down to about 35 lbs or so.

The basic thinking is seductive: plywood is a laminate, so other than protecting it from water, why put other laminates [fibreglass] on the surface - so just adhere the edges and seal the surface.

The downside will be constant upkeep to assure that any bare wood gets sealed. I would imagine that there would be noticable spot discoloration if unpainted wood was used, but it would depend on the upkeep.

20 lbs sounds too difficult, check the bare wt of the ply used and that would give initial idea without any glue or seal coat. Using the 16-2 shearwater as a S&G example the overall ply area would be about 48 sq ft.
 
Last edited:

Mac50L

Paddler
Joined
Aug 18, 2014
Messages
240
Location
South Island, New Zealand
Have any builders out there built a super light stitch and glue Kayak?
I am thinking :
4 mm thick plywood - 6 or 4 panel design
I thought you wanted light? Use 3mm, single chine or no chine and tortured ply. One piece curved-over deck, without deckbeams.
Fiberglass only the bottom & inside where you sit with 4 oz. glass
Why? That's adding a lot of weight.
Seal the seams with thickened epoxy and glass the outside of the seams with bias cut 4 oz. glass
Use paint to seal the rest of the boat
Use a foam seat
Now you're talking light. How about my latest one, 13 kg into the water for testing? My last 2 were 18 kg fully equipped, rudders, hatch covers, rudder pedals etc. Yes, could knock a kg or so off that if needed.
The boat would only be used for flat water and near shore
Just day paddling?
Is 20 pounds possible with a 16 foot long boat?
10 kg - possibly though the epoxy would need to be minimal and one coat of paint.
 
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