New Solo Daytripper Design & Build

[sailsman63]

Time to start putting some of this beast together permanently. Some of the joints are not suitable to be glued, but they do need to be sealed. I need a bedding compound. I choose... Butyl rubber. It's inexpensive, stays flexible, and lasts forever. Not an adhesive.


This particular batch is from the old, ratty butyl roll out in the shed. All the bugs were on the edges, so they got cut off when I trimmed it down.
Please forgive some of the blurry photos. I was having a terrible time with the camera yesterday.

Layed out the Gar plank on the form. Some of the pencil marks weren't as visible as I'd hoped, so needed to mark in with some splines. (This will be fixed going forward - need to use a different pencil for this.)
As advertised, I only marked out the starboard side. I then stacked with the matching piece of stock for the port side. Small #6 wood screws just countersunk so that I can run the stack through the bandsaw.


I did end up putting a screw through somewhere I shouldn't have, so I have a permanent repair to make a little later. What's a build project without at least one "oops" scar?

I didn't get any pictures of the bandsawing operation. Nothing too exciting there, and when family hangs around to help out, it's often simpler to just get on with it.


I've got a little workstation figured out on the bench, since we don't have a proper bench vise. Cleanup done with a handplane. If you're looking at the really scruffy bandsaw line, you're not wrong. I swapped out blades after making that cut.

Sanity check before removing the batten spline:

I did miss getting a photo of how the splice is supposed to work, I'll try to catch that next time.

The trickiest thing about the gar planks is this winding bevel on the inner edge. Those who understand traditional lapstrake will note that there is typically a rabbet cut into the keel timber. For this build, I thought that that would just move the winding bevel to another location, so here we be.
Also: every project needs some shop-made jigs, right? This little thing lets me set the correct angle on the bevel that the next plank will land on.


All in all, didn't get as far as I hoped. Learned some stuff, so hopefully efficiency will improve as I work in.

 

[sailsman63]

Sorry for the delay on the update.

Well... It's been a couple of project days...

Here's a closer look at how the splices are supposed to work. The screws are for test fitup only, they were to be replaced with rivets. The near edge to be riveted through when the next plank is installed.


I did finish cutting the plank bevels on the gar planks, got some oil on them, and did a test fit.

If this looks a little off....

While the test fit was in place, I marked out sections of the next plank up.

I did, in fact, cut out these planks, but no photos.
In between, I started rolling up some butyl worms - This stuff is crabbier to handle than I anticipated, and doesn't want to stick in place until it has been squished for a while.


Remember how I said up-thread that this build might include destruction and warning? Well, this is as far as I got:


And this is where it remains for now. I ran into some issues.

First, I believe that running that backbone without the traditional rabbet was a strategic error. I traded one set of challenges, (cutting a winding, partially undercut rabbet) for another: The seam line where the gar planks were to meet just never worked out right, and left an open "V" that would be a pain to seal or finish. The bevels that I cut were never quite right either.


The planks also fought me as I tried to line up the transition from the butted bottom to the book-parallel at the ends. I removed them, intending to just splice in a bit more.

However, I ran into a materials issue as well. I managed to break one of my splice plates, and a test rivet in some of the plank stock also managed to create a crack.


Both of these were sound wood, and both had pilot holes for the nails.

I've come to the conclusion that the oak is just too brittle and prone to splitting for this application. I don't doubt that it is possible to successfully rivet oak planks -if they are thicker. I'm currently thinking a minimum of a half inch or so, which would be fine for a heavy work boat, but is far too much mass for a pack canoe.

That means that this entire project needs a re-think. Options that I see at this time:

1. Chose another wood species. Cedar is more typical, but it's not cheap, and I was hoping for a species that could take a bit of bumps. I have access to cherry, which I think would be more conformal and far less prone to splitting, but I hate to use all the nice cherry for something like this
2. Scrap the entire lapstrake in favor of another building method. This would mean sourcing other materials, which I had intended to avoid.

Either way, this project will not be completed to get on the water this summer. Whatever form I go forward with will probably be moved into a winter project. I'm not exactly in a good mood about this.

If I do continue with the lapstrake method, I will be pulling the backbone/keel piece and replacing with a properly rabbeted version. I also think that fitting those gar planks would be simpler if I take the eased transition out of the stems - more like the yellow sketch line. This is not uncommon in lapstrake skiffs and such, and since this is a fairly sharpish forefoot to begin with I don't think it would hurt the hydrodynamics much.

Thoughts or ideas? I'm willing to listen.

Sorry if this (temporary?) end to the project leaves you disappointed, but I can't keep throwing more effort into something that just isn't working.

 

[Gamma1214]

Bummer but at least we're learning along with you.

As much as I love the look of Cherry, I'd suspect it would be at least as brittle as the Oak, especially when cut that thin. I'd look for something faster-growing and harder to split like Sycamore or Willow. You'd give up some strength with either but you'd also lose a bunch of weight. Both species are typically just cut into blocking though so boards might be hard to come by.

Take a breather & see if you can find the motivation to tackle it again this winter.

 

[sailsman63]

I'd suspect it would be at least as brittle as the Oak, especially when cut that thin

That might be. I'm kind of playing with what I've got available.

I'd look for something faster-growing and harder to split like Sycamore or Willow.

Unfortunately, Sycamore isn't a thing near me. I'd end up paying several $ per board foot.

Willow, if I understand correctly, is nearly as soft as basswood. Not so worried about "strength", but that's too "soft".

 

[RickR]

Thank you for sharing your thinking, process and results. I've enjoyed following along. I think your instincts to pause and reset are true. I look forward to seeing this boat built.

 

[Alan Gage]

Elm might be available from a local sawmiller. It can be difficult to saw and dry without the boards warping but it's relatively hard and has interlocking grain so it does not split easily.

Alan