|Canadian Canoe Routes
|Update - How to built a 40lbs Osprey
|Page 1 of 2|
|Author:||Michel vd Hoven [ October 5th, 2006, 5:57 am ]|
|Post subject:||Update - How to built a 40lbs Osprey|
Just an update on my Osprey building project.
I just put a short building log with progress pictures on my website.
Unfortunately the files are quite large and thus slow to load... I'll try to improve that.
My website in still under construction, so it's not that advanced (yet)...
Michel, The Netherlands
|Author:||RHaslam [ October 5th, 2006, 6:56 am ]|
Very nice work! Have you started to sand the inside yet? That's the very nasty part. I have paddled my strip osprey a few thousand kilometers....i'm sure you will love it.
|Author:||Doug [ October 6th, 2006, 5:08 am ]|
My 40lb Osprey ended up weighing 50lbs.
WR cedar, cherry, basswood, 6oz glass.
In the end I did not want to sacrafice strength & durability for lightness.
|Author:||BBQ Dude [ October 6th, 2006, 8:02 am ]|
Fantastic vessels both....Doug, that inlay pattern is phenomenal!
Man, I admire people with talent....
|Author:||Dan Lindberg [ October 9th, 2006, 1:04 pm ]|
Doug and Michel,
If you're serious about building light canoes, check out George Robert's site/ "doctine". To my knoweldge, he is the only builder "pushing" the "construction method envelope".
In general, he promotes less weight in wood, more glass weight and the correct ratio of glass to resin, ie, about 50-50. I believe his general layup is 1/8" strips with 2-3 layers of 3.2 oz tight weave cloth.
Using these methods, my 18.5 Winisk has a hull weighing 40 lbs (no trim), this is with 3/16 strips and 2+2 layers of 2.3 oz glass. The current project, a 18.5 modified Quetico, has a hull of 43 lbs, from 1/8 and 3/16 strips and 2 layers of 2.85 oz glass plus 2 layers of 2.3 glass. (The Quetico got a different layup because the all 2.3 had some marginal strengths in one axis's, the 2.85/2.3 layup is better ballanced and up to 3 times the breaking strength of 1 layer 6 oz, and both are significantly lighter.
My original goal was to build a 18.5 ft tripper under 50 lbs without giving up strength/durablity, I'm not there yet but am close. I'm projecting about 53-54lbs finished on the Quetico.
|Author:||RHaslam [ October 9th, 2006, 1:20 pm ]|
Interesting stuff Dan. You got any other references? I'd like to try multiple layers on my next canoe. My second winish and first quetico have just about had the biscuit after a few thousand kilometers of club use. One six ounce layer is not sufficient for prolonged hard use up here. I haven't subjected mytwo new boats with the ten ounce cloth to the same beatings, so I don't know how they will hold up, but they didn't come out substantially heavier than the ones with six ounce.
|Author:||frozentripper [ October 9th, 2006, 2:36 pm ]|
Interesting numbers, I built my !5' 9" Huron for durability first, and the final weight came to 53 pounds, not too bad considering there can be a couple of big, hairy guys paddling it.
The cloth was standard 6 oz and includes an extra abrasion layer on the outside bottom... the contribution of glass to total weight was only 15%, so most of the weight savings could have been made in the wood, with some loss of stiffness and durability.
Have you guys checked out Lightjay's construction method in his last boat, the one that was to have made the cross-Canada journey... IIRC, he used thin marine plywood strips which he claims reduce weight most. He didn't want to reveal his building method because of possibly getting a patent on it... he might be willing to outline some how-tos now.
The thin plywood strip method along with stiffening ribs seems like a very good way of building a hull, at least in theory... I have an old Pinetree fiberglass canoe built that way, except the core is aluminum mesh, and it's been through hell and back, a very durable and shock-absorbent hull because of flexibility. Souris River canoes are also built this way and are known for being light and durable at the same time.
Anyway... actually I have no plans of building another canoe at the moment, I'm happy with the two I have now. If I were to spend the time to build another, it'd likely be along the lines of the Souris River construction method. And if we could get Lightjay to spill his guts on how he built his last boat, it might get me to build another.
|Author:||Dan Lindberg [ October 10th, 2006, 12:59 pm ]|
No, no other places to see other strip construction methods.
Robert's was/is kind of an abrasive fellow, and got in a lot of arguments and got kicked off a number of building BB's. He still posts on occasion over on the Wooden Boat BB. Basically, in general, everybody building using the std 1/4 strip / 6 oz glass would argue with him, and it would degrad to a shouting match. There maybe a few other builders who have tried his multiple thin layer glass, thin wood methods but I don't know who or where they might be.
I tried it because when I was 1st gathering info on building strippers, it seemed like everybody I talked to had failures of one type or another when using 1 layer of 6 oz glass.
On my 1st, I used a 2ed layer in and out in the football, but it got way to heavy, 72 lbs. (That and because it was my 1st, I still wanted it to look good, so I put on too much resin. Now I'm going for strength and light weight.)
If you think about it, if you take the less wood/more glass to an extreme, you'd remove the wood completely and just make it of resin and glass, with maybe a bit of foam or cross ribs for stiffening.
I revised my glass materials after getting and reviewing the specs for various weaves (from the large weavers, there are only a few).
I suspect that I can't get much lighter using the strip method, (while maintaining strength and durability) and may try a "kevlar" canoe to get the weight under 50.
There is a site run by a guy who has made a few using the Moran methods.
As for the plywood strip stuff, Thompson Boats and likely other manufacturers used plywood strips starting back in the 40's, layed up in a lapstrake fashion.
BTW, building very light canoes is easy, many have done it, starting with Rushton back in the late 1800's, but it's very hard to make a strong/tough yet very light canoe. The epoxy/kevlar method "might" be the best yet for the home builder. Of course it doesn't look anywhere as nice as a canoe that shows a bit of wood.
|Author:||Moonman [ October 25th, 2006, 3:28 pm ]|
I've followed your posts for the last couple of years on this and the Bear Mountain forum and I was wondering why you don't just build a super light boat that is maybe a bit LESS strong.
You've got a few boats now that are very strong but a bit heavier than you want. Why not an 17-18 foot boat that uses only 2 layers of 2.5 oz cloth, super light trim - say cedar, sitka or butternut, cut down very thin but then sliced in half length-wise and glued (laminated) for additional strength.
Using 3/16 strips on the bottom/football moving to 1/8" strips around the bilge and up to the shear (as I surmise you did on your last boat).
I bet you would get to 45 pounds for a Winisk and 48 for the Quetico. Sure you wont be able to really abuse the boat but you can choose it on easy summer trips where abuse can be minimized and then use one of your other boats for fall/spring trips, with maybe more gear and tougher (more abusive) conditions.
Jusy my two cents. I think it would be a great idea if someone would set up a lightweight boat building forum where all the tips people have used over the years can be found.
I've picked up a lot of tips from various sources but it takes a long time to find all the available info.
Anyway, good building.
|Author:||DougB [ October 25th, 2006, 4:56 pm ]|
A lot of good boatbuilders on this site. I wouldn't mind giving it a go over the winter. Roughly what is the overall financial investment to build one of these?
|Author:||Moonman [ October 25th, 2006, 6:32 pm ]|
Main costs are in the strips. 600.00 - 750.00 if you buy strips ready to go with the bead and coves already routed. 200-400. if you can make your own strips.
Epoxy varies widely in costs. Most popular is west System, MAS and Raka. But a lot of builders use system 3, east and many others. For an average sized boat you're looking at 150-250.00. Fibreglass 5.00 - 7.00 per yard.
Hardwood for trim probably 200.00
Then there are all the little things like sand paper, hand toolds you may not have, clamps etc. etc. If you build one boat you'l probably build another so don't let the cost of tools stop you.
You'll enjoy it tremendously and there is lots of support out there through books and forums like this one.
If you haven't already bought it, get a copy of Canoecraft. That will be the best starting point.
Hope this helps.
|Author:||RHaslam [ October 25th, 2006, 7:05 pm ]|
first time builders are faced with some initial expenditures that you won't have to repeat if you build again.....
If you build yor own strong back, using laminated plywood pieces, count on 200.00....if you make it out of 2 by 12 x 18, probably two boards, arounf 50 to 75 bucks.
A fiberglass kit with resin, hardner, pumps and glass will probably be close to five hundred if you have to pay to have it shipped.
if you can find a local mill that cuts cedar, you can get it rough for between a dollar and two dollars a board foot. if it's totally clear, 60 to 70 board feet will build most larg-ish canoes.
I think 200 might be a bit high for hard wood, depending on what you use....white ash can often be found for about three bucks a board foot.....I wouldn't think you would need more than fifteen or sixteen board feet......
varnish....50 bucks for the good stuff, 20 for the hardware variety, which i always use. brass screws.....20 bucks...brass stems...50 bucks
A lot depends on how fancy you want to go.....brass seat hanging bolts are expensive...plain steel ones are 25 cents......
I'd say if you are handy and have access to tools and a good lumberyard, your first canoe will probably be just under a thousand. Your second one should be about 700. i'm hoping to build 3 this winter, probably 700 each.
|Author:||DougS [ October 25th, 2006, 7:35 pm ]|
If you want to build a light-weight boat, why not use 4oz s-glass? You get the weight savings but the same strength as 6oz e-glass. Apparently it is a bit harder to work with though.
|Author:||Dan Lindberg [ October 26th, 2006, 2:47 pm ]|
What did we get started here?
Moonman, wow, I'm amazed anybody remembers me. I don't post all that often, and haven't been on at Bearmtn for a couple years.
Yes, the strips on this project are 3/16 in the football, decreasing to 1/8 on the sides. The weight savings from the wood went into more glass to make it stronger and a bettter/more ballanced strength.
The trim, yes, I'm planning to make the seats/thwarts/yoke laminates, haven't done it yet though. I thought about doing that for the gunwales but right now they will likely be phil mah, I will cut them down to reduce weight.
A less strong canoe, well, yes I could but, I'm a large guy, 340+lbs, plus wife and gear so there will be a lot of weight in this canoe, and it's main purpose is BW/Q campouts. Hard to walk back if the canoe fails catastrophically.
Glass weight - yes, many canoes have been built using just 4 oz, but I believe that single 6 oz isn't strong enough. I talked to too many builders who had glass failures with just the single 6 oz.
For very light canoes, I believe John W has said he's made them with just 1 layer of 2-3 oz glass, but they were delicate. And I'm not interested in building delicate canoes.
Also, just saying 6 oz or 4 oz isn't very descriptive, the weavers make/offer lots of different weave patterns and weights.
For example, from Hexcel, what I suspect is often sold as the "standard" 6 oz cloth, may actually be plain weave E glass 18x18 at 5.8 oz/yd^2 with a breaking strength of 220 by 220, (warp by fill).
They also offer in S glass, a plain weave 24 x 22 at 3.64oz/yd^2 at 140 by 130 lbs/in. And another plain weave S 30 x 16 at 3.7 oz at 175 by 260 lbs. And finally in a S twill weave a 56 by 56 at 4.4 oz at 300 by 330 lbs.
For perspective, I used 2 E glass weaves on this project,
a plain 40 by 32 plain at 2.85 oz at 210 by 160 lb strength,
plus a 60 by 56 plain at 2.31 oz at 195 by 75 lbs.
I believe the most important thing is to minimize the wood weight, (increasing the glass weight) use a cloth that is very thin, (to minimize resin use), thin cloth can come from either a fine weave, smaller fibers or both. Note that while both of the weaves I used on this project were a plain weave, because they are of small/fine fibers, they are thin cloths.
Also note, fine fibers are stronger then thick fibers, and 2 cloths of a fine fiber are stronger then the same weight of a thick fiber cloth, assuming both have similar weave patterns.
And yes, laying thin glass and multiple layers of glass is a lot more work then a single layer of thick glass. I usually wetout 2 layers at a time, using a nylon brush to apply the resin, lightly working it in as I go. A wet out takes about 4-5 hours. I roll and tip fill coats and they only take 20-30 mintues, and the thin cloth only takes 1 or 2 very light coats and it's ready for sanding. The inside only gets 1 very light coat to protect the glass.
Money - yes, about 1500 for the 1st, the 2ed about 850, and 3rd about 650, but this is using the best/most expensive material, ie, System 3 Clear Coat and SB 112 for fill. And multiple layers cost a lot more for glass.
If one wants to build a canoe cheap, use Raka or US Composites resin, what $100 to $150, get glass from Thayercraft, at about $1/yd, you just have to buy a full roll. If you use the 1 layer, and 1st timers should, you're talking 15-18 yds, use cheap or free wood. You could probably build a canoe for $150 to $250 if low cost is the object.
|Author:||DougS [ October 26th, 2006, 10:19 pm ]|
That's interesting. I hadn't seen Hexcel's data sheets until now. I was under the impression that a 4oz s-glass (#4522) was roughly the equivalent of a 6oz e-glass (#7533). From Hexcel's data though, this is clearly not the case. In fact, given the same fill and weight, there appears to be only a marginal improvement in strength with s-glass.
Here's an interesting thing to look at. Compare style #3733 to #7533. Both are plain weave e-glass, 18x18, 6oz. The yarn is slightly different though. I presume the 7533 is the typical marine/boat cloth used. #3733 is almost 50% stronger in one direction though. Why isn't it used more often? Useability? Ability to conform to complex shapes? Abrasion?
Dan, how well did your cloths wet out and conform to shapes? That sure seems like a stronger layup than the usual 7533. Why would you use the two different cloths, instead of 2 layers of the 2.85oz? Do you know if your cloths had a finish on them? And where would you buy it from, directly from Hexcel? I'm curious, it's interesting to learn about this stuff.
|Page 1 of 2||All times are UTC - 5 hours|
|Powered by phpBB® Forum Software © phpBB Group