Building a light weight expedition canoe

[oregonfarmer]

Hi Folks,
I've been lurking for quite some time, reading everything here as I contemplate an upcoming boat building project. I am thinking of a lightweight strip or composite build for expedition-style trips. I've built a number of boats over the years, one stitch and glue kayak, a strip sea kayak, and a couple of skin-on-frame pack canoes, so I'm not new to building. An all-composite build has an appeal as a new challenge, either using a sacrificial stripper as a form, or using the fabric-form method outlined by Rizetta in his book. The kind of boat I'm thinking of would be able to carry loads for trips of 1-2 months, and handle open water on big rivers and lakes, and moving water in the class 1-2 range.

The first step, of course, is to come up with a design. I've had my eye on a kruger-type decked canoe for a long time, and have the JEM northwind stripper design in hand, but before I move forward on cutting out the forms, I'm wondering if this is the best option for me. I realize that "lightweight" and "expedition boat" don't necessarily go hand in hand, but I've been intrigued by the number of projects outlined here that really push the envelop in this regard, so I think you folks might have something to say on the topic.

At 52, I'm definitely not getting any stronger, and I'm concerned that a decked canoe would end up a little on the heavy side for me in the decades to come. Could a slightly shortened northwind (say 16-16.5 ft) be built in the low to mid 40's either with strips or composite-only? Would a relatively deep solo with a spray cover be a better option?

Any thoughts greatly appreciated.
cheers,
chris

 

[ppine]

Hi Chris,
Great to hear the thoughts of an experienced boat builder. My reaction to a "lightweight expedition boat" is that you can't really have both together. You have to be able to depend on an expedition boat a long way from help. Making it light is a function of materials but not construction. I would want it to be a little heavier than average. Making it deep with a spray cover eliminates some weight and provides capacity for long trips and big waves. Kevlar type materials can build some strong but relatively light boats. I like stitch and glue also.

If you live in Oregon, where are you planning to take this expedition boat?

 

[Alan Gage]

I had similar thoughts/needs/desires.

These threads will cover my design and build process for two versions of the hull. Version 1 went 30 days and version 2 went 43 days.

Version 1 was cedar strip. Version 2 was composite using a sacrificial wood form.

Solo expedition build

Last build of the season before the water opens up. No doubt open water will appear before I'm done but there will still be plenty of cold and windy days to work in the shop. This will be, hopefully, my ideal solo expedition canoe....or at least a step in the right direction. The aim is to...

www.canoetripping.net

Composite Bloodvein build

Version 1.0 was a success so V2.0 will be a carbon/kevlar version. Best case scenario is cutting 10 pounds, from 48 to 38. I think 7 or 8 pounds will be more realistic though. Made a couple very minor changes to the hull. The entry and exit lines were pretty hollow on V1 which made it a little...

www.canoetripping.net

I also built this boat for longer and more severe trips but it hasn't been on a trip yet so I can't say how it will paddle in the real world. Day trips have been good though. I used 1/8" strips and kevlar/carbon fiber.

Barrens build

'Tis the season for building. A high volume solo for big loads and big water. This is, I hope, the boat I should have had on my last trip. 16'x32" with 21" shear in the bow, 14" in the center, and 18" (or maybe it was 19") in the stern. Lots of flare in the bow. Couple inches of rocker in bow...

www.canoetripping.net

Alan

 

[oregonfarmer]

In the short term, I am planning on using this on the Columbia River, and coastal bays, but longer term in more exotic locations, like the barrens, yukon. Missouri/Mississippi, etc. I would like something that can stand up to adverse condition on large waterbodies, but can also portage without hurting myself.

Yes, I have seen those bloodvein and baren's builds, and that has been the impetus for thinking along these lines. If Alan could get his weight down around 40 lb-wise then I wonder if I could get a decked canoe for less than 50 without making it too fragile? It seems like it would have to be an all composite boat though. By my thinking, a decked boat loses a little weight by not having gunnels and with a lowered shear at the ends, but then gains it back and then some with the deck and coaming. I like the idea of a rudder, and that would add a little weight too.

I guess what I need to decide is whether a deck is worth the weight penalty or not, so any thoughts along those lines would be helpful.

 

[Alan Gage]

Decked canoe for the Missouri, coastal, and Columbia where portages aren't much of a thing (but wind is).

Open canoe for trips that will require portaging.

They could be completely different hull designs or the same hull below the water line with the only change being the shear height and deck.

Although I can certainly see advantages I don't think I'd enjoy a traditional canoe trip with a decked canoe. I'd constantly curse the extra weight during portages and would not enjoy stuffing gear under the decks and then fighting to get it back out.

Sounds like a fun project!

Alan

 

[stripperguy]

Seems like you're gonna need two boats!
I used to think nothing of carrying my 62 lb stripped comp cruiser and my full pack for miles at a time. These days, I'm looking for every advantage and weight savings I can find.

Any of the modern materials will work for your needs, if you want stiff then be sure to use carbon on the inside. Some of those basalt/inegras are esthetically pleasing.
Any given geometry (I'm talking section, not hull design) will benefit from increased hull thickness. The benefit is a function of the thickness cubed, ie, double the thickness, then the strength increases by a factor of 8.
How to add thickness without a big weight penalty? Foam, specifically Divinycell. Their H80 PVC foam is 5 lbs/ft^3, you won't find a better bargain than that.
We've had the discussions here, and I've had many at the dinner table at home about the best method for one off composite builds.
I think we have a consensus WRT build procedure:
Wrap male plug with whatever cloth desired.
Wet out with epoxy resin, leaving stems open.
Remove from the plug, close up stems.
Add foam stiffening where desired/necessary, vacuum in place.
Add inner cloth.
Finish as desired.

 

[oregonfarmer]

Seems like you're gonna need two boats!
I used to think nothing of carrying my 62 lb stripped comp cruiser and my full pack for miles at a time. These days, I'm looking for every advantage and weight savings I can find.

Any of the modern materials will work for your needs, if you want stiff then be sure to use carbon on the inside. Some of those basalt/inegras are esthetically pleasing.
Any given geometry (I'm talking section, not hull design) will benefit from increased hull thickness. The benefit is a function of the thickness cubed, ie, double the thickness, then the strength increases by a factor of 8.
How to add thickness without a big weight penalty? Foam, specifically Divinycell. Their H80 PVC foam is 5 lbs/ft^3, you won't find a better bargain than that.
We've had the discussions here, and I've had many at the dinner table at home about the best method for one off composite builds.
I think we have a consensus WRT build procedure:
Wrap male plug with whatever cloth desired.
Wet out with epoxy resin, leaving stems open.
Remove from the plug, close up stems.
Add foam stiffening where desired/necessary, vacuum in place.
Add inner cloth.
Finish as desired.

Yes, the answer is always more boats!

I was afraid the conversation would turn towards vacuum bagging a foam core. I haven't wanted to contemplate that! Is the equipment for that worth it for a one-off build?

Thinking harder about this, I think I will proceed with a decked, all composite version. Is it possible to build such a boat in the 16 foot range under 50 lbs, or is that a total pipe dream?

 

[Gamma1214]

Welcome to the site Chris. I've never built anything composite so I can't really help with that but 2 thoughts:

1) I would think the deck could be built far more lightly than the hull and they make 2.5oz fiberglass cloth (maybe even lighter). I would think you'd just need something rigid & waterproof, right?

2) I wouldn't want to fight gear in & out from under enclosed decks and I'd think a nylon cover would be lighter and easier to work with anyway.

Whatever direction you go, please consider a build thread. It sounds like an interesting project and, while not necessarily my cup of tea, I'd be interested to follow along.

 

[tketcham]

Thinking harder about this, I think I will proceed with a decked, all composite version. Is it possible to build such a boat in the 16 foot range under 50 lbs, or is that a total pipe dream?

Hi, Chris,

I think it's possible but you'll have to be obsessive about weight savings as the primary goal and that's going to mean giving up some aspects that contribute to durability. I paddled a 17.75' Clipper Sea-1 canoe on several multi-day trips on the Columbia River (big winds, big waves) and it worked well. The Sea-1 weighed about 56 lbs or so, which isn't too bad, but it was a hassle carrying it, even on short put-in/take-out portages. I'd end up carrying it sideways on my shoulder and one time actually dragged it through the sagebrush for a quarter mile instead of trying to carry it. I did consider building a custom removable portage yoke but never got around to it.

I think you could get the weight down below 50 lbs by shortening the length, though you'd give up some tracking ability, and by eliminating the gelcoat, which provided impact and abrasion durability. Perhaps a minimal gelcoat surfacing, limited to where the most abrasion is expected. The retractable, foot-controlled rudder could also be eliminated. I found that I rarely used the rudder and could trim the canoe for better tracking by sliding the seat forward or backward as needed. I guess it depends on whether you expect to be out in somewhat extreme wind and waves.

And although (partially) decked, the Sea-1 still required a spray cover in big waves. Regarding decks vs covers, I think a cover that is relatively easy to remove or open up to access cargo for portaging is the way to go. (That's what I had with my Clipper 17' Prospector.) The rear cargo area of the Sea-1 was open enough to be able to easily stash a large bag/pack without a hassle but I would have to stash additional dry bags and even a food barrel in the bow section. I think having to do several portages in a day would get old because of the repacking needed each time. Not as bad as a sea kayak but still. Unless you're expecting to have big waves crashing down on the bow/stern, a well-designed cover might be a good way to reduce weight. I wonder if you could design removable decks for easy access to cargo?

Fun project!
Tom

 

[Alan Gage]

I was afraid the conversation would turn towards vacuum bagging a foam core. I haven't wanted to contemplate that! Is the equipment for that worth it for a one-off build?

The equipment required for vacuum bagging is pretty cheap. Just a vacuum pump and some plumbing.

The consumables for vacuum bagging definitely have a cost (and waste) associated with them (bag, peel ply, blotter, etc) and it takes a lot of time to properly execute successfully.

Foam is expensive but you can buy scrimmed foam that can be shipping in rolls rather than sheets and does not require any heat bending.

I've done a few composite hulls and my most recent one I vacuumed the foam core in place and wetted out the remaining cloth by hand. It went ok but left plenty of room for improvement. Each time I do a composite hull I end up questioning if it's worth it. I still don't know.

No doubt you can build a decked canoe at 50 pounds or under but it's not going to be a bomb proof expedition build. You can't have everything.

Alan

 

[oregonfarmer]

So much to think about! Yes, I hope to post my project when I get there. Thank you all for your ideas.
Chris