Excelsior, an Atkin 'Cruising Canoe'

Thanks, PAR. I've built birdsmouth porch columns before, so I'm familiar with the basic method; these masts will just be longer and daintier. Between that and your scantlings, I should be able to giterdone.

And this will definitely be a cruiser. There's no one around here to race against, except for bass boats, ski boats and the occasional Hobie Cat -- and I don't like my chances against any of them. The area isn't exactly a hotbed of sailing action...

I appreciate the suggestion, but I'm a woodworker to the bone. I've never touched any other material, except for some welding experience way back when. So it'll probably traumatize me enough just learning to sheath the bottom and garboards. Baby steps, you know....

The next boat after this will probably be a cruising sharpie. When I get around to that one, I'll revisit your idea.

 

Pictures of the quick-and-dirty hull model I'm building:







For some reason, the first two pictures remind me of rattlesnake bones. Maybe I should name the boat "Rattlesnake," when I build her.

As I thought, the twist in the planking at bow and stern is pretty wicked; I'd hate to try doing it with full sheets of plywood. It's probably no real problem with the half-dozen strakes of planking shown in the plans, though -- especially in glued plywood.

 

Oh that's not very bad at all, as far as twist in the section and will be easy to plank, even if you used a full width and length, scarfed panels. Have you used the proper amount of bottom rocker?

 

Yes, 6 inches. I laid out the lwl on the molds and the profile, and matched them during assembly.

 

That's going to be pretty quick if you can keep it right side up. There's not a lot in the water.

 

Doesn't look too badly twisted in the picture, so long as you let the planks define the stem shape and resist the temptation to force a curved stem.

The difference between twisting a plank (which can be difficult) and a conic projection (which simply bends) is not great, so a minor adjustment to the planview should fix any problems.

So far my boats all have one plywood sheer plank and straight stems and go together easily - but I cheat by using a constant flare angle. However, the bilge planks have a distinctly twisted appearance on some, but went in easily - I allowed them to find their own path and trimmed the stem foot to suit. Some folk dislike a straight stem; sometimes I add an external stem with a slight curve for esthetics.

 

She'll have straight stems with the forward one raked one inch, per the plans. But I'll probably do a two-piece stem instead of a rabbeted one, like I did on my flat-bottomed canoe.

That planking isn't as easy at the stems for a solid sheet as you might think. It looks to me like the fat rounded topsides combined with the fine entry at the waterline, with a plumb stem connecting them, creates a hollow compound curve. Hopefully tonight I'll have time to try planking my little hull model, and we'll know for sure.

Atkin shows six planks to a side, so doing lapstrake in solid cedar or glued-lapstrake plywood should handle it just fine. And I'll probably plank it just for the looks, even if it turns out to be possible to use solid sheets of plywood.

Here's a look at a smooth-sided one built on commission by the Northwest School of Wooden Boat Building, in 2007 & 2008; my guess is that they strip-planked it. But I've sent them an email, hoping to get hold of either the instructor involved or the client.

 

I forgot that you are following a plan so you do not have design freedom. It's hard to tell without lines but the boat in the pic appears to have quite a severe hollow. In that case you may have to use several planks; it's never a bad thing to follow the designer's suggestions!

When the sheer flows forward from a station to the stem, it can follow either the chine edge or the sheerline, but not always both without a buildup of tension at the edges. If one is able to adjust one line so the sheer approximates a conic the stresses drop sharply; I'm not sure if this is always the case but so far it has always worked out for me. The exception was Wee Lassie: I tried to merge the bottom 2 planks into one as they looked parallel all the way: I found out J. Henry Rushton knew more than I did ...

In a small sailboat I built I unintentionally introduced a slight hollow by gluing the inwale and chine logs to the sheer plank while flat: when they were bent, the inwale and log were compressed and the tension in the ply introduced a perceptible hollow along the sheers. It did not measurably change the shape the designer (Par) planned for below the waterline and it looks nice: an example of creative stress perhaps!

 

OK, Paul. I should never have doubted your experienced eye.... I finally got around to laying a flat sheet of heavy paper against the side of the cardboard model. It not only laid down nice and flat on it like a sheet on a bed, it was also surprisingly straight when I marked and cut it. Well, surprising to me, anyway... It would be no trouble at all to plank the boat with full plywood panels.

Think I'll do the glued plywood lapstrake planking anyway, though; it'll look nice. And with a watertight compartment at each end and a bulkhead under the deck between the two cockpits, I shouldn't need much more in the way of framing. I'll take the weight I save and put it in the bottom as ballast, I guess.

 

I haven't forgotten this build. But between the money and time I've spent on lawyers this year defending my mother-in-law's will, and the money I've spent on engineering, flood control, building permits, and all the other crap that goes into erecting a simple !@##$%^&* pre-manufactured home in this area, I don't have a lousy few hundred bucks to spend on it right now.

So I'm going the model route again, to figure out the details... and to feel like I'm doing something. But this model will be 1 1/2" = 1' 0", so that 1/8" will equal one inch. I wandered over to the local hobby shop this afternoon when I got back into town, looking for materials. Since the LOA of the model will be 32", I wanted to pick up some 1/32' thick x 36" long veneer for the planking and bottom, to avoid splicing sheets. No luck; everything he had in stock was only 24" long. He hesitatingly offered to special order me a couple of 1/32" x 12" x 36" sheets and guesstimated they'd run me about $25.00 each. But he explained he usually has to order a minimum of 6 sheets, and he's afraid he'll get stuck with whatever I don't buy and wind up with it collecting dust on his shelves.

He wasn't being a jerk. After bs'ing with him for a while, it became obvious that he's in a position where shelling out for a hundred bucks of unsalable inventory actually hurts. After years of successful business, he's been hit with a double whammy. First of all, the recession has reduced discretionary spending on stuff like RC model airplanes, model cars and model railroads.

Secondly, he's been hit hard by internet businesses like Amazon, who ship to California without charging sales tax. He has a steady stream of potential customers who waltz into the store, look over and handle his inventory, pick his brains to figure out what they want and need -- then go home and order it on their computer.

As he says, "I can compete with the internet prices. But my margin is so tight I can't afford to eat the sales tax, too."

Ah well, back to the subject... almost. I think I mentioned here or in another thread that I bought a 3' x 6' pedestal drafting table at a yard sale a while ago. I decided it's going to be my lofting floor for the model. As a matter of fact, I'll probably just tape the sheets of wood for the molds and bulkheads to the table, and draw to scale directly on them.

So when I dragged the table out, dusted it off and shined it up, one thing became obvious: people should not be allowed to own X-acto knives, unless they've been properly trained and have a certificate attesting to their undiminished mental capacity. The vinyl cover has everything from 6" block letters to fluffy clouds carved into it, along with an incredible array of random slashes. And the cover would be a b**** to completely replace. The edge of the table is scalloped or coved, and the vinyl is wrapped around with its edges under a thoroughly tacked metal channel. I know that sounds a little muddled and unclear; I'll do a picture tomorrow.

But I have a cure. A while back I had to cut through the tub surround in our front bathroom, to replace a rotted water line between the tub faucet and the shower head. I bought a cream-colored 4' x 8' sheet of FRP (fiber reinforced polymer; 'Marlite'). I re-covered that end of the tub surround from the top down to just above the faucet, using a tube of Loctite Power Grab for adhesive. When it set I caulked the edges, and everything is all hunky dory at shower time.

I was left with a piece of the FRP larger than the drafting table, and I'm going to use it to resurface the top. The sheet is smooth on one side, and has a slightly pebbled surface on the other, so obviously I'll put the pebbled side down.

I bought another tube of the Loctite today, but I'm not sure I'm going to use it. It seems kind of permanent, and I'm also worried about getting a wavy surface unless I tooth-trowel it onto the entire tabletop. Although the stuff in the bathroom looks fine, I can feel the lines of adhesive under it when I run my hand over the surface.

So I went googling this evening, and found that the standard cure when re-covering a tabletop is just to fasten a new layer over the old with double-faced tape. I think I'll give that a try. The worst that could happen is that the FRP doesn't stay put in this hot climate, and I wind up gluing it down after all... I can handle that.

 

By the way, I wound up buying a few sticks of 1/16" x 4" x 48" airplane balsa instead. They're only three and a half bucks each, so I guess my artistic vision has caved to financial reality.... I'll live with it. If the lap joints look too bulky, I'll bevel both plank edges instead of just the lower one.

 

==============
Troy, I'm not sure whether you're familiar with this technique or not so I'll just blurt it out. When you need to bond balsa or wood you can use thin cyano glue and baking soda. Sometimes with cyano, the glue is absorbed so quickly that there is no bond but if you put a little finger round of baking soda
in the joint and put cyano on it it will form a rock solid fillet right now. Just don't get cyano and baking soda on your fingers at the same time-it will hurt.
Looking forward to seeing the model!

 

That's a new one on me, Doug. Thanks.

 

I have the drafting table set up in a spare bedroom and ready to use, except that I've misplaced one of the scales (or rules, or whatever you want to call them) for the drafting machine. That's going to cost me about thirty bucks... ouch. I only paid a hundred for the whole setup. Of course, a new Vemco V-Track the size of this one lists for $815.00 (with no table to clamp it to), so I guess I can't complain.

I went ahead and attached the FRP with Scotch Brand double-sided tape, and it seems a little iffy; I may wind up going to a drafting supply house and getting some stronger stuff. We'll see, though. The top edge of the FRP had a wave in it and didn't want to lay flat, so I slapped it down with a piece of clear packing tape all the way across.'

I'm not impressed with the previous owner or owners of this setup. Everything on the drafting machine that can be tightened needed to be tightened; everything on it that can be adjusted needed to be adjusted. But getting it shipshape was a pretty good education in how it's put together and how to use it, and it works like a brand-new one now.

Here are pics: one with the pedestal extended all the way up; one with it all the way down, and one with it at a comfortable working height and angle. And of course, it'll lay totally flat down to 30", too.

I've also included a picture of one of the cute, fluffy little clouds carved into the old surface...

I was going to run down a scale and start doing the molds and bulkheads in the morning, but the wife called from the other house; she has a honey-do list for me. Gee, it's nice to have some time off work...

 

Troy, on the model I'm building I wanted it to be about 60" long because ,at that length, the weight was ideal for building as an RC boat as well about as big as I could handle in the car. That caused a problem: there was no scale that fit any on my scale ruler. The biggest was 3"=1' which made the model 54" long and the weight too light. So I fooled around with it and came up with a scale of 3.375"=1', length 60.75" and weight of 16.8lb. Now that I had that sorted I had to make up my own scale ruler which I did using a strip of poster paper. One foot of the scale was marked down to inches and one inch was marked to 1/8th inch readable to 1/32nd inch. Worked well....

PS- thats a fancy table!