After getting the planks on, it was time to work on the bottom.
In the interest of finishing Cabin Boy as soon as possible, I decided to use 3/8" okoume marine plywood for the bottom, rather than the splined cross planks I'd originally planned on.
None of my boat building books explained how to do this, so I had to improvise. Here's what I did:
First, I laid the plywood sheet on the bottom of the boat. Cabin Boy's bottom curves a lot from fore to aft, so I weighed both ends down with a number of large art books. I always knew I'd find a use for those books.
Then I carefully traced the lines of the garboards and transom on the underside of the plywood.
I then used my jigsaw to cut out the bottom. I left 1/4" extra all around, just in case. Here's what I ended up with:
Cabin Boy's bottom, cut from 3/8" okoume
I tried it on for size, and it fit perfectly. Note the books, fore and aft.
Trying on for size
I'd planned to fasten the bottom with 3M 101 sealant, backed up by silicon bronze screws, but unfortunately, 3M has discontinued this old reliable product.
After doing a bit of research, I chose 3M 4200 as my bedding compound. This is similar to the popular 5200 sealant, but has much less bonding strength. This allows the sealant to remain flexible and removable.
I'm sure some people are thinking I should have epoxied the bottom, but I now have a bit of experience with both epoxy and flexible sealants, and it just seemed to me that the flexible sealant was a better solution for this big, critical joint.
Bottom line, if the joint starts leaking with the 4200 in it, I can fix it by removing the screws and prying the bottom off. If the epoxied joint had a problem, I'm not sure what I'd do.
I laid down a nice thick bead all around the edge and with Helena's help, carefully positioned the bottom on the boat, and screwed it down.
Bottom attached with 3M 4200 bedding compound and silicon bronze screws
I had some 4200 left over, so decided to fill the counter-sunk holes with it. Not sure if this is an approved use of the product, but it seemed like a good idea at the time. If it turns out to be a problem, I'll blog about it.
So, putting on the bottom turned out to be easy-peasy. Hardly any challenge at all.
I suddenly realized I was pretty vague about the next steps. Lucky for me, this weekend happened to be the Maine Boat Builder's Show, in Portland. It was a great opportunity to check out the 'competition' (and steal some ideas), so I headed on up.
The show was held in the Portland Company's large boat yard complex. You walked through room after room filled with boats, not to mention all the 'accessories' that make boating and banking practically synonymous.
Some of the many small boat builders at the show
There were too many booths to take in on a one-day visit, but most catered to the push-button, luxury crowd, so I was able to focus on two missions:
- looking carefully at the 2 dozen or so small wooden boats that had been built by professionals
- visiting the booths of the several vendors who catered to the traditional boat builders
Many boat building schools showed off their student's handy work
In inspecting the boats, I was particularly interested in 3 things:
- how the boats had been finished
- what the builder's had done with the gunwales, or top edge of the boat
- how the builder's had attached the thwarts, or seats
Linseed oil finish
My favorite finish is just plain linseed oil. I like the natural, work boat type finish, and even like the way it turns black after a few years. This is how I had planned to finish Cabin Boy, when I still thought I'd plank him in Cedar with copper rivets. But I didn't think this would work too well with epoxy-smeared plywood. But next time, this is what I'm going to do.
My next favorite was a scheme I hadn't thought of: a two-tone combination, with a bit of bright work. Again, the result had the kind of no-nonsense, work-boat type look that I like. The bronze knees on the thwarts were a nice touch. I really like this boat.
One color, plus bright work
Another one-color dory
Almost as nice were the boats that were finished with one color, plus some bright work, like the two above.
An 'instant' boat, simply finished
One boat I didn't particularly like was an 'instant' boat, finished all in white. The color, plus the lack of structural details like ribs or seat risers, made the boat look more like a fiberglass than a wooden boat.
Yes, I was born in the wrong century.
So, the show helped me decide how to finish Cabin Boy. I'm going to use a two-tone color scheme, with a bit of brightwork... probably the inwales, which will be made of oak and shouldn't take much abuse. And the mahogany transom, of course.
I also got some excellent ideas on how to build the gunwales, and seats. More on that later.
Finally, also of much interest were the few vendors who supplied traditional bits like bronze fittings (below), oars, rigging supplies, and rope that is meant to look and feel like traditional rope, but is made from modern materials.
A wide assortment of traditional bronze fittings were available from a number of vendors
Eventually, I'd like to refit the Blue Moon with all bronze fittings and traditional lines and rigging.
That reminds me... I must go buy a lottery ticket.
So, a great show, and I was very impressed with Portland, itself. A nice city with a revitalized water front. Lots of restaurants, Irish pubs, and the young people who make them jump. Well worth a stop if you're cruising through the area.
Tomorrow, I flip Cabin Boy over!
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