Light boat

tx river rat · Post by **tx river rat** » Fri Oct 05, 2007 8:54 pm

Question for ya'll
If a man wanted to build a light version of say the laker or freedom 11
Used tape on seams inside and out and then put on three coats of epoxy graphite mix on bottom and up three inches on sides would this be enough with just saturating the inside.
Ron
This space for Matts standard reply about thin plywood and light builds
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Post by **jem** » Fri Oct 05, 2007 11:34 pm

if you just use the tape but not thicker ply, you'll lose stiffness.

hairymick · Post by **hairymick** » Sat Oct 06, 2007 6:20 am

Ron,

I reckon it MIGHT work but personally, I wouldn't like to try it. It would lose a lot of impact resistance and the little weight loss you would achieve, seems hardly worth the risk to me.

If the weight thing is REALLY important to you, I would suggest you investigate a different type of core material to make the boat out of.

I am aware of a small canoe 12' , I think that an Aussie boat designer built from balsa and completely encapsulated in epoxy and very light woven matt. I think it weighed around 12 kgs or about 26 pounds.

Kayak Jack · Post by **Kayak Jack** » Sat Oct 06, 2007 11:20 am

Rat,

I'm not sure where you want to use the boat. Without glass inside and out, rocks would be a danger. If you ever get hung up on a rock - particularly a pointy rock - the wood can actually flex inward. Unprotected by glass, you will likely hear a ripping, splitting sound. This is also likely to be closely followed by someone shouting (in a voice that sounds eerily a lot like your own) "OH SH!+"

Bubbling sounds are maybe next.

If weight is a strong consideration, think of a smaller boat. Maybe and undecked canoe, or a canoe with only short decks. Also, think 1/8" plywood (good stuff, not cheap stuff) and glass all over the outside and on the bottom of the inside.

Matt, Mick - please correct me where I may be misleading here?

Post by **jem** » Sat Oct 06, 2007 11:34 am

-If you go with just taping seams, you really should go with thicker ply for stiffness.
-Fiberglass is tougher to scrape through than just epoxy.

It's tough to get around those generalities.

hairymick · Post by **hairymick** » Sat Oct 06, 2007 3:46 pm

Jack,

I agree completely with you mate. I have ben thinking on this overnight.

Something like a Laker hull, with small minidecks and light rub rails (and a thwarte) could be made very light. My Laker hull weighed practically nothing before I put the decks on.

I reckon, using 1/8th ply and the lightest fibreglass matt you can find AND EPOXY RESIN inside and out, you could have a tough boat that will stand up well to normal use and still weigh less than 15 kilos.

The only way to make a light boat is to use light materials and to use them sparingly and carefully when building.

What I think is critical here is the safety of those who will be using the boat. I would never compromise this by attempting to reduce or eliminate the fibreglass matt which is the guts of your boats strength.

Here are some of my thoughts on fibreglass tape only boats.

I think it is an abomination. The tape will re-inforce the seams and that is all it will re-inforce. The rest of the boat will be rlying on the strength of the ply - only. Unless you are using much thicker-heavier ply, to achieve similar strength to a completely sheathed hull, you run the risk of putting yourself and anybody else who paddles you boat in an unsafe situation.

Kayak Jack · Post by **Kayak Jack** » Sat Oct 06, 2007 3:58 pm

I concur, Mick. If I KNEW that my boat would not encounter rocks or logs, then it could be a lot weaker hull. No boat of mine has ever had (and likely never will at any future period) that luxury.

It seems magnetic to rock. And, since there is a lot of iron ore around in Michigan and Canada, maybe it is?

Well, Rat, there it is. I don't have a lot of experience, but I do have at least one year of experience - repeated about 50 times.