fitting outside stems

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tptbum
Posts: 29
Joined: Sat Jun 09, 2007 9:17 am
Location: Ann Arbor, MI area

fitting outside stems

Post by tptbum »

Hi guys - it's going pretty well for a first timer so far I guess - but every time I get to a new stage I get pretty paranoid. I think the paranoia increases as the amount of work that would be lost if I completely screw up increases!

I read three or four books before I started this project (cottage cruiser). I have re-read all of the sections dealing with attaching the outside stems . . . . and I am still pretty frightened by the process.

Cutting the tails off the strips flush with the inner stem seems easy enough at the bow of the boat, as you go around the corner the angle of the stems becomes flatter - meaning that if you just saw evenly you end up with a much wider swath than you need. I am not really clear on how to proceed from there. "Canoecraft" mentions "mortising the stem" I assume that means creating a channel in which the stem can be recessed, and that you use a wood chisel for this. I may have missed something - but I didn't find real clear instructions.

Hear is my real fear -
when I was shaping the inner stem I followed the contour of the hull and it described a rolling bevel - from very sharp at the bow to very flat at the keel. This means that if I get down to the inner stem with my mortise there is very little of the strip left glued to the stem, what if they become detached? Will the strips being glued together maintain the shape and then you used epoxy to attach the stem.

Any advice?
Anybody got real good pictures of the process?

Thanks -
John
BearLeeAlive
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Re: fitting outside stems

Post by BearLeeAlive »

Hey John.

I am building my first canoe right now too, and am currently putting the outer stems on. One I glued on last night, and the other I have mostly prepped to put the other one on. Like all other aspects of building the canoe, once you figure out and start to install the outer stems, it will become easy to understand what to do. The first one took me probably 2 or more hours to prep, the last on maybe a good hour or so.

Your thinking sounds mostly fine. On the front face the strips are cut and finished flush with the inner stem, but as you round onto the bottom of the hull there will be a point where the hull starts to become wider than the outer stem. At this point you need to start cutting a square recess (dado, groove) into the strips the exact width of the stem, and down to the inner stem keeping the bottom of this recess nice and flat.

What I learned doing the first one, and did on the second changed a bit, and it went way better on the second on. One thing I did was to plane (I actually used a spokeshave) where the strips meet flat a little bit, never making this flat plane wider than what the stem is. I then used a 1/2" chisel and at the corner of the bend, and the back of the stem, I went down to the inner stem to confirm where its exact center was. I then taped an 18" flexible rule that is exactly 3/4" wide on the center line, now laying nice and flat due to the planing. I scored along the edge of it, took the rule off, and scored some more. Then it was almost all (very sharp) chisel work, and I took all the cedar strips down to the inner stem.

I have to fly out the door for a few hours, but I will take and put up some photos of what I am doing, and what it looks like, when I get home. It will likely be later this evening.

I would imagine there are lots of good tricks of the trade other much more experience builders have, and I am eager to hear what they have to say, and maybe incorporate them into my next build, and there most definitely will be another.
-JIM-
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Glen Smith
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Re: fitting outside stems

Post by Glen Smith »

Ealger has some good pics of the process at this link: http://s12.photobucket.com/albums/a237/ ... 2QQtppZZ36
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Patricks Dad
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Re: fitting outside stems

Post by Patricks Dad »

Jim wrote:
I then taped an 18" flexible rule that is exactly 3/4" wide on the center line, now laying nice and flat due to the planing. I scored along the edge of it, took the rule off, and scored some more. Then it was almost all (very sharp) chisel work, and I took all the cedar strips down to the inner stem
I'm not sure I follow this but you seem to be saying that you cut your mortise for your outer stem to be 3/4" wide the entire length toward the keel line. You should instead taper the outer stem to be narrower as it progresses from the bend toward the keel line. The mortise therefore needs to also be tapered from 3/4" down to say 3/8". Be sure to make your outers stem an inch or 2 shorter than your inner stem.

I may simply be misunderstanding what your trying to say above. Forgive me if I didn't follow you.
Randy Pfeifer
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tptbum
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Joined: Sat Jun 09, 2007 9:17 am
Location: Ann Arbor, MI area

Re: fitting outside stems

Post by tptbum »

What is the purpose of tapering the outer stem?

Doesn't that make the mortise harder to chisel in?

john
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Patricks Dad
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Re: fitting outside stems

Post by Patricks Dad »

My impression is that:
Tapering the outer stem allows you to leave more wood on the strips where they connect to the inner stem. Visualize the wedge of space (filled by the strips) between the inner and outer stem if you had not tapered it. Up near the keel end of the stem, that space would be a fairly narrow slice of wood. If you taper the outer stem, the strip which is glued to the inner stem will have more material.

I also think that the look of the tapered stem is a bit more pleasing but that's a personal preference.
Randy Pfeifer
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David James
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Re: fitting outside stems

Post by David James »

To add to what Randy said, if you taper the outer stem down to 3/8", and if you plan to install a 3/8" brass stem band, the end of the tapered outer stem (3/8") will be hidden under the stem band for a nice clean look.

Dave

pictures would help here, but I don't have any.
"If given six hours to chop down a tree, spend the first four sharpening your ax." - Abraham Lincoln
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Glen Smith
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Re: fitting outside stems

Post by Glen Smith »

Randy is right.
tptbum
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Joined: Sat Jun 09, 2007 9:17 am
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Re: fitting outside stems

Post by tptbum »

Actually now that I've read your posts the book makes a lot more sense to me.

thanks -

john
BearLeeAlive
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Re: fitting outside stems

Post by BearLeeAlive »

Patricks Dad wrote:I'm not sure I follow this but you seem to be saying that you cut your mortise for your outer stem to be 3/4" wide the entire length toward the keel line. You should instead taper the outer stem to be narrower as it progresses from the bend toward the keel line. The mortise therefore needs to also be tapered from 3/4" down to say 3/8". Be sure to make your outers stem an inch or 2 shorter than your inner stem.

I may simply be misunderstanding what your trying to say above. Forgive me if I didn't follow you.
Randy, I did indeed take the 3/4" wide stem all the way back. I am just following John Winters instructions for a tapered stem (just the leading edge tapers from 3/4" at the curve to 1 1/2" at the shear.) It worked out just fine. From a structural standpoint I see no problem, as any of the strips glued to the inner stem are not effected where they bond to the stem. I can see it being a nice aesthetic touch though.

I planed, spokeshaved and sanded down one of the stems most of the way tonight and it looks great. If keeping at 3/4" along the keel, I think I would do a curved tail at the end of it, as it would finish nicer than the blunt end.

I did take some photos of the last stem and the the recess I cut into the hull to accept it.

Here is where I first planed a flat plane very close to the final 3/4" wide.

[img]hhttp://bearleealive.smugmug.com/Other/Canoe-Build-Kite/IMG1413/1237464035_9qUBx-XL.jpg[/img]

This is where the outer stem stops along the keel line.

Image

Another shot of my carving. John, you can see how it transitions from a groove to being flush as in rounds the front curve. Both ends of my canoe transitioned a bit differently due to the shape. I imagine all canoes will be a bit different too.

Image

Here is the stem glued and bound.

Image

A shot along the edge of the stem where it was inside the channel I carved. As you see, it makes a nice clean transition. The one I sanded out looks great.

Image
-JIM-
tptbum
Posts: 29
Joined: Sat Jun 09, 2007 9:17 am
Location: Ann Arbor, MI area

Re: fitting outside stems

Post by tptbum »

Wow - Jim,

That's really nice, thanks for sharing.

I have made some mistakes in mine and the stems are gonna be a bit ugly. I hope that filling my gaffs with epoxy makes them less ugly - if it's too horrible I can always paint!

I think it's one of those things where when you look at the boat it looks great and when you look at the details you see flaws - again not bad for a rookie!

John
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Patricks Dad
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Re: fitting outside stems

Post by Patricks Dad »

Don't sweat it. You will see the flaws when you're done but nobody else will (they will be simply overwhelmed at the beauty and the accomplishment).
Randy Pfeifer
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BearLeeAlive
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Re: fitting outside stems

Post by BearLeeAlive »

Very true, Randy. We are our own worst critics.

With having a fairly extensive woodworking background, I tend to try for perfection in all joinery. When gluing up 3 strips at a time while bending, curving and twisting them, there is a point where good enough becomes well, just good enough.
-JIM-
pumpkin
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Location: North Dakota

Re: fitting outside stems

Post by pumpkin »

BearLeeAlive wrote:I tend to try for perfection in all joinery.
I tend to think that perfection is a goal not a destination.

Matthew
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