A Raven from Scratch

[Jim Dodd]

A Graphited bottom will certainly reduce the abrasion, maybe increase the speed !
The double layer on the inside, should give you plenty of stiffness.
You certainly don't need to double layer the full inside. Up to about the 2 or 3" waterline, and some up to the sear, in the seat area should work.
I know we are all throwing ideas at you ! Thats up to you, to incorporate the ones you like ! That's how we improve our builds.

Just throwing out another idea here. Has anyone tried pulling a Kevlar copy, off their Raven ?

You could a reduce the weight, by at least 10#.
Easier to port, and it's fun to see the water at the shearline, from inside the canoe.

Build the Raven on the cheap, using one layer in and out of 4oz E-glass, then pull a Kevlar copy from it !

Yes ! Two canoes !

I know there is a cost, and time factor.

I can tell you. You will love a Kevlar copy, of any hull you like !

A very thin, inside strip layer, in the football, works great, to add the stiffness.

Add some aluminum gunnels, flotation chambers, and you will be a Happy Paddler !

From My experience, I've been paddling the Composites a lot more !

Anyway ! This has been a fun thread, and we are all enjoying your build so far !

Thanks !

Jim

 

[Jim Dodd]

On a different note !

This is the first time I've viewed the Raven plans .

To me. It seems to have way too much rocker, for a 15'4" hull, and it's narrower than my Pearls, which have almost no rocker.

Me ? I would cut that rocker in, at least half. I think you will gain speed, at a very little loss of handling, especially with that short of a hull. You will also be able to run shallower.

Maybe you can get Alan to run it through Delft Ship, and see how the numbers come out !

Alan ! Alan !

 

[Gamma1214]

Thanks guys. I appreciate all of the advice.

This is the second of 3-4 hulls that I'll build while I'm gathering enough Sumac to strip a hull. I'm hoping to find one that I really like and then build that hull again using the Sumac. In the process I want to use a variety of woods that are readily available locally and see what they look like as opposed to the traditional Cedar. I know I'll pay a weight penalty by using heavier woods and I'll try to minimize it w/ outfitting choices, strip thickness... perhaps even adding microballoons to the expoxy (if I can find clear instead of white).

The only differences in glass layup from the last build would be moving the extra football layer to the inside and lightening the s-glass to 4 oz instead of 6 oz. I was planning to just use one layer in & out but the football inside makes sense from a strength standpoint.

I agree that Tamarac above waterline or mixed with Northern White Cedar would look awesome. Perhaps on a future build.

I'd like more rocker than the Freedom Solo that I built. It was great on the lake portions of the Steel River loop last fall but I want more maneuverability in the fast water portions. My biggest concern w/ the Raven, at this point, is do I really need all the extra volume and will the epoxy stick to the Larch? The adhesion question I can answer with the test panel. The other can only be answered by throwing it in the water.

If it's too much of a beast, maybe I'll drop it off in Geraldton on the way home.

 

[memaquay]

Lol, you won't be dropping it off, you will either love it, or burn it in a raging fire of regret in your back yard.

John Winters developed the Raven as a river tripping canoe, hence the rocker. I really like the rocker, gives you nice loose stems for when the going gets tough. Performs really well in big bad waves, and is a lot easier to turn than the Osprey. Might not be the preferred hull for Satan's double blade, but for single stickers who can make canoes go straight, it seems to motor right along, keeping up to or passing tandems. When conditions are appropriate on the flats, I've got it heeled over, so rocker doesn't really enter the equation then.

As I've said before, people either love it or hate it, there is very little middle ground. It has the reputation of being a very large solo hull, which it is, but people who have soloed for their entire lives in tandems might find it too small for their liking, and people who have soloed in the usual small hulls might find it gargantuan. Switch hitters, or hutters, or whatever the proper term is, will not like the hull because of the rocker, dedicated white water enthusiasts will not like the hull because of the asymmetrical hull and rocker, and lightweight trippers will not like the boat because of the weight.

For a classless fella like me who sometimes carries a dry bag with 72 beer in it, and a chainsaw and gas, and assorted other creature comforts, it rounds out to the perfect hull.

 

[Gamma1214]

Sounds like the trick might be to tote the Stihl along and bring beer. Tragic.

 

[Jim Dodd]

Yes. Rocker , dictates the kind of water it is used in.
I've paddled my Pearl in the BWCA lakes, and rivers of Northwest Iowa.
With it's minimal rocker it works great.
It will definitely leave the Raven in it's wake, in a flat water situation.
On the other hand ? The Raven will out shine my Pearl, in class II rapids.

It all boils down to what kind of water you are paddling.

Yeah. Like Mem. I too prefer the single blade, with the hit and switch paddling, when I'm in a hurry, or against the wind.
For normal pacing, I heel my Pearl, and C-stroke. No hull banging either.
The tumblehome, on the Raven, as well as my Pearl, works great in either method of stroking.

So as another side note ? Why not add some rocker to the Freedom Solo ?

More Ideas I know !

Jim

 

[Gamma1214]

Why not add some rocker to the Freedom Solo

Two main reasons: 1) I hesitate to start modifying plans without knowing what I'm doing and, so far, the Freedom would likely be the boat I'd take on a return trip to the BWCA; I like it that well on lakes.

2) The WPA Solo Canoe Rendezvous is close enough that I could haul a few boats to it if someone would care to paddle one before they build. This is somewhat complicated by my seat placement (I like the seat much further back than the standard solo position) so anyone wishing to try it would probably need to kneel (I'll always have the balance point open for kneeling situations) but at least they could get an idea. (they could also see what the different woods look like because I doubt I'll build a Cedar hull anytime soon)

As I get a few more hulls under my belt and know more about what I liked / didn't like about each, I may reach out to @Alan Gage for some help with modifications or a hull recommendation but, for now, I'll build ones which have plans readily available.

 

[Cruiser]

Gamma, I found with my Freedoms, the secondary stability is great and if you lean it hard on the side, it turns on a dime

 

[Gamma1214]

OK, test panels are done... Yes, 2 panels.

The first is the one shown earlier and is air-dried Larch (aka Tamarac). I edge glued it, used a scraper to knock off the excess glue then took a horseshoeing rasp to it to level it. I intentionally used the rough side of the rasp to gouge it rather deeply figuring I might have a better chance of hitting resin below the surface (better to find it now than after it looks like a boat).

The panel rasped well and I went to the fine side of the rasp and then to 60 grit paper. It seemed to leave minimal residue on the paper so I think it will sand well. I trimmed a scrap of 4 oz e-glass wet it out w/ epoxy and, visually, it seems to have stuck (the cloth wet out nicely, didn't slide around TOO easily and the wood certainly looks wet. I'll be busy through the weekend so I'll, most likely, break it Tuesday or Wednesday to see what kind of bond I actually achieved.



With the next panel, I kind of wandered off the reservation a little in an experiment to lighten the build (perhaps considerably). Allow me to explain:

When I built my Freedom, I used about 2 gallons of epoxy (1 & 1/3 gal of resin & 2/3 gal of hardener) which, at almost 10 lbs per gallon, accounts for nearly 1/2 the weight of the finished canoe (45 lbs). Not much we can do about that, just part of the drill, right?... maybe not.

My buddy that owns the garage where I built my boat shop, is a recovering machinist turned gunsmith who now builds benchrest rifles. There is a class called "light varmit" where all builds are right up against the weight limit and he says that he mixes micro balloons into the epoxy on these guns. Micro balloons are microscopic glass balls. They have the consistency of dust and flow like water. They can be mixed with epoxy as a filler and essentially replace epoxy with air. I've read where some have mixed them 50:50 (by volume... they weigh nothing), supposedly, without significant loss of structural strength. The only downside (and it's a deal-breaker for me) is that they're white and leave the epoxy looking milky.

My research led me to McMaster-Carr who claimed to have clear microballoons although the customer service lady said they were white. Figuring that, "so is the e-glass before I wet it out", and "it's only money... why not?", I ordered a mid-sized bucket. (2 qts @ 0.5 lbs)



This leads us to the second test panel. I had a leftover bulkhead from the freedom build (I'd cut both float tank bulkheads from the same panel) so, while I was mixing epoxy, I grabbed enough e-glass to cover it, donned appropriate breathing apparatus (this stuff gets airborne easily... again, think very fine dust), shut off the furnace (to reduce air circulation) and, after wetting out the Tamarac panel, I measured out enough balloons to equal approx 1/2 of the volume of the leftover epoxy and folded it in until thoroughly mixed. It was the consistency of very thin pancake batter and looked like milk.

I poured to onto the Aspen panel & squeegeed it to wet out the fiberglass. It seemed to wetout nicely, definitely increased the coverage and was certainly not white on the panel. It is cloudier than epoxy without balloons but, in my mind, the jury will be out until it's dry. If it's clear (or even clear enough), I may mix up a batch 50:50 and use it as a fill coat. I am thinking that it would easily fill with just those 2 coats and the epoxy savings might account for 8-10 lbs less boat to portage.



I'll be interested to see how clear it is when dry. I'm optimistic that it will work but I suspect I'll have to sand a lot more to get the hull smooth. I usually don't sand much at all but the white seems more pronounced where the boards are uneven.

 

[Cheeseandbeans]

Not sure this is helpful, but I know a builder who adds West System 410 to epoxy to make it sandable for fairing and filling canvas weave. I can’t speak to its transparency.

Bob

 

[JohnSand]

Honestly, for a 10# weight saving I would put up with cloudy finish. Paint the outside, or call it a dream sequence.

 

[Cruiser]

When I built my Freedom, I used about 2 gallons of epoxy (1 & 1/3 gal of resin & 2/3 gal of hardener) which, at almost 10 lbs per gallon, accounts for nearly 1/2 the weight of the finished canoe (45 lbs). Not much we can do about that, just part of the drill, right?... maybe not.

I totally agree that epoxy weighs a lot and contributes a lot of weight ... however ... a lot of the epoxy in that 2 gallons ended up in the grunge cup. On my last Freedom Solo 16'3" with 6 oz E glass... the external glass/epoxy was 6 pounds and the internal was 5.5 pounds, about half of what you mentioned here, just don't want you to have unrealistic expectations.

If you are looking at weight savings for this build, you have already taken a big step selecting 4 oz glass. The thickness of 6 oz glass is 8 mil thick and 4 oz is 6 mil, so a 25% savings in glass layer weight.
Unfortunately, when I modeled this for my new build, it became apparent, that you needed to consider three separate sources of weight in a glass epoxy layup 1) what goes into the wood 2) what is used to bury the weave and 3) what is used to wetout the cloth ..... only the last one changes in a standard layup, so the weight saving are going to be there, just less than you may expect.
To try and optimize weight, another tack to take is a thin seal coat to control how much gets absorbed into the wood, it does not need to be saturated, basically just sealed, the epoxy just needs a few mil of penetration for strength. This is a good reason to look at System 3 epoxy with that 72 hour recoat without sanding IMO. You can apply the seal coat and not have to worry about additional surface prep and you can control how much epoxy absorbs into the wood (and minimize that contribution).

The weight distribution for a boat is about 1/3 in the hull, 1/3 in the glass and the final 1/3 in the trim .... that is "roughly" true, until you swerve to the dark side and intentionally add weight, to one of the three, for whatever reason.
So in a 45 pound canoe, you could expect a cedar hull to weigh around 15 pounds .... the Tamarac choice gives a hull around 15 X 37/23 = 24.13 pounds (compared to cedar) ... so that choice alone cost you about 9 pounds in hull weight.

I am going to research adding the spheres again, when I did last time, I think I concluded it would adversely affect the strength of the layup, but it was while ago ... so I will check again.


Brian

 

[Alan Gage]

Some good advice from Brian (and others).

I'm not exactly sure what your target goals are or how strict you're trying to stick to those targets. It sounds like you're having fun coming up with different ideas and I can certainly respect and relate to that. I've certainly done things that other people thought sounded silly and they worked out great. Sometimes you just need to try something to see what happens. What's the fun of doing the same thing as everyone else?

The only thing I'll say, since you've been talking about cutting weight, as someone who has tried to build lightweight, is that there is not one place to concentrate your efforts and there is not one place you can ignore. If your main goal is to cut weight then you need to carry that out every step of the way. True weight savings only comes from the cumulative effect of every step of the process. In that case Tamarac would seem to be a bad idea.

On the other hand if you're set on using Tamarac, and are looking to cut weight everywhere else to make up for the initial weight penalty of the wood selection, then I think that makes perfect sense. You get to use a unique wood and in the end you end up with a canoe that doesn't weigh any extra.

Either way I look forward to watching how this one turns out.

Alan

 

[Jim Dodd]

Things that come to mind, using the micro ballons.
Making the epoxy thicker, also makes it more difficult to spread out, and squeegee. This may require more epoxy, to cover the same area.
It will take more time to mix, as you first need to mix the epoxy, add the ballons, and mix again. This will reduce working time.

If micro ballons were good to use in a laminating situation, such as a canoe hull. They would be using them.
The Ballons were designed to be added as a filler, for gluing things together.

You may go to a lot of effort and expense. Only to find the Micro ballons set you back.

Peel ply is another option. It has it's draw backs, working around a multi directional surface.
I can testify, I had troubles with it.
It can reduce the amount of fill coats though.

Question . How flexible is Tamarac, compared to cedar ?

Maybe cut strips at 1/8", and do a test panel..

Thinner strips, is a great way to go, to reduce weight. They are easier to work with too.

I'll agree, reducing weight, needs to be done in all phases of the build !

My seats, weigh way too much !! I'm willing to carry the extra weight, as my comfort, out weighs the extra weight.

Yup ! Cut some 1/8" thick strips and glass both sides, one with a double layer, and give it your torture test.
Flex both directions, and prove the inner double layer is stiffer.
I'm still on board with the extra layer on the outside ! It will add stiffness, and durability. The extra layer on the inside, only adds stiffness. Scrape that single layer , then scrape the double layer, see what you come up with.
I'm glad to see a willingness to experiment !
Also, glad to see another build thread !

Thanks !

Jim

 

[Cruiser]

Things that come to mind, using the micro ballons.
Making the epoxy thicker, also makes it more difficult to spread out, and squeegee. This may require more epoxy, to cover the same area.
It will take more time to mix, as you first need to mix the epoxy, add the ballons, and mix again. This will reduce working time.

If micro ballons were good to use in a laminating situation, such as a canoe hull. They would be using them.
The Ballons were designed to be added as a filler, for gluing things together.

You may go to a lot of effort and expense. Only to find the Micro ballons set you back.

Peel ply is another option. It has it's draw backs, working around a multi directional surface.
I can testify, I had troubles with it.
It can reduce the amount of fill coats though.

Question . How flexible is Tamarac, compared to cedar ?

Maybe cut strips at 1/8", and do a test panel..

Thinner strips, is a great way to go, to reduce weight. They are easier to work with too.

I'll agree, reducing weight, needs to be done in all phases of the build !

My seats, weigh way too much !! I'm willing to carry the extra weight, as my comfort, out weighs the extra weight.

Yup ! Cut some 1/8" thick strips and glass both sides, one with a double layer, and give it your torture test.
Flex both directions, and prove the inner double layer is stiffer.
I'm still on board with the extra layer on the outside ! It will add stiffness, and durability. The extra layer on the inside, only adds stiffness. Scrape that single layer , then scrape the double layer, see what you come up with.
I'm glad to see a willingness to experiment !
Also, glad to see another build thread !

Thanks !

Jim

Need to be a little careful here, going to 1/8" strips will impact the strength of the composite formed and there are already several steps being taken with thinners strips and lighter glass.
Also ... putting the layer on the inside isn't about stiffness, it is about strength/impact resistance .... for anything other than abrasion resistance, there is little value to that outside layer in an impact situation, if it is a choice between inside and outside.

 

[Gamma1214]

Paint the outside, or call it a dream sequence.

The dream sequence idea has merit but I won't paint. Not only would that add weight where I'm trying to cut but I like the look of the wood.

If micro ballons were good to use in a laminating situation, such as a canoe hull. They would be using them.

Question . How flexible is Tamarac, compared to cedar ?

From what I've read, the micro balloons are widely used in lightweight aircraft laminations but, of course, I am expecting a higher frequency of impacts. As to flexibility... I have no idea. Having never worked with Cedar, I can't compare but the Tamarac seems about as flexible as the Aspen & Sassafras and, probably, a little more flexible than the Cherry. I may reduce strip thickness to 1/8 but I think that would reduce hull strength more than I'd like.

You get to use a unique wood and in the end you end up with a canoe that doesn't weigh any extra.

That's really what I'm trying to do: mitigate the weight penalty of choosing the heavier wood. And, yes, I'm having fun playing with it. I'm not sticking strictly to weight goals just trying to keep it reasonable. As Brian says, I can lose 10 lbs by ditching the Tamarac & going with Cedar. I could probably lose 10 more by using Balsa.

Sometimes you just need to try something to see what happens.

Exactly. At some point, I fully expect to screw up a hull so badly that it winds up burning in the back yard as Mem suggested earlier.

The jury is still very much out on whether I try micro balloons on this hull. In my initial wet-out experiment, the 2/3 epoxy, 1/3 balloon mix seemed to spread well, wet-out nicely and I really only had one issue but, for me, it might be a deal breaker...

That issue, of course, is the clarity. You see, one reason strippers appeal to me is that I love the look of wood but the balloons left a hazy look where thickness was minimal and remained downright cloudy where the strips weren't completely flush to the adjoining strip. I'll make another test panel this weekend and try to sand it until it's absolutely even & smooth (fair?). At that point, I'll try the balloons again to see if I can live with the results.

The downside of this is that I'll actually have to sand the hull instead of getting it close and counting on the epoxy to self-level. Everybody talks about how much they hate sanding so I pretty much skipped that sucky part on my Freedom. Of course, that probably caused some thicker (heavier) areas also so maybe I can save weight by actually doing it right and sanding the beast.

Thanks to all for the comments. I'm happy to share and (sometimes) I learn something too.

 

[Ripple]

Is balsa wood a real option? I have never built one, but really enjoy these threads. It even inspired me to buy plans. I've tried to build stems, but, they bow off the form a bit. ( Don't compleatly conform to form). And have a very good feeling I would not be able to cut strips uniformly, since my tools are limited. But with less expensive wood I would be more inclined to try. Your boats, and plan, to build a few is great, good luck. They look great.

 

[Jim Dodd]

Need to be a little careful here, going to 1/8" strips will impact the strength of the composite formed and there are already several steps being taken with thinners strips and lighter glass.
Also ... putting the layer on the inside isn't about stiffness, it is about strength/impact resistance .... for anything other than abrasion resistance, there is little value to that outside layer in an impact situation, if it is a choice between inside and outside.

The Beauty of 1/8" strips ? You glass the outside, glass the inside. If you are not happy with the results ? Add another layer to the inside. That is how I build my Composites.
It's a great way to keep the weight down. When adding additional layers to the inside, you just glass the bottom, not the entire hull !

I would do it in a heart beat ! Using Tamarac, or Cedar ? Yes ! I'd go for it !

Sometimes you need to think outside the box !

Oh, the extra layer on the outside ? Definitely adds strength and stiffness !


Jim

 

[Jim Dodd]

Is balsa wood a real option? I have never built one, but really enjoy these threads. It even inspired me to buy plans. I've tried to build stems, but, they bow off the form a bit. ( Don't compleatly conform to form). And have a very good feeling I would not be able to cut strips uniformly, since my tools are limited. But with less expensive wood I would be more inclined to try. Your boats, and plan, to build a few is great, good luck. They look great.

No need for stems ! Go stemless, is much easier, and just as good !
A stemless thread, all my builds are stemless.

Pearl

I want to Thank everyone for for the helpful suggestions on my next build. I Wrestled with the idea several nights in bed. I wanted a canoe that I really like, and would be light enough for this Old Man to portage in the BWCA, and yet one that I could handle on the Iowa prairie streams, that I...

www.canoetripping.net

Jim

 

[Cruiser]

Gamma,
The idea that thinner strips aren't going to be as strong, isn't exactly due to the wood strength, that is actually is a minor component. You are creating a composite structure when you glass both sides of the wood. The woods job is to hold the glass layers in position, not provide any meaningful strength.
The distance between those glass layers and holding them there is where the strength comes from. The closer the layers are to each other, the lower the strength, so a 1/4" strip gives a higher strength structure than 3/16" strips (or 1/8") due to the gap it provides between the layers.
It's a bit of a ballet optimizing the glass layer thickness and the gap thickness to get the properties you want in your layup.