JEM Watercraft

the mounting method and height is up in the air right now,height can be adjusted with spacers at crossbar to outrigger mount, trial and error will see if leeboard / daggerbord is needed.

MM

jem wrote:Sabalo will draft 3-4" under average load. Midship total height is 11". So deduct accordingly.

Thanks Matt. That's perfect, that means that setting the deck height of the pontoons to about 1" below deck height of the Sabalo under average load will place them at about a 2" draft on flat water under average load. That is enough to provide just a little lateral buoyancy without much resistance under paddle, and not too much heel on a reach. It does mean that the pontoons will take the weight when ashore due to the hight difference, but I don't think that's much to worry about.

I like the look of makenmend's cross bars but I don't think I'll need anything quite that sturdy. I was thinking of just laminating a cross bar about 3" wide from 2 layers of 8mm ply, or maybe 3. What do you think?

Sounds like a job for a length of bamboo to me. Light, strong, simple, cheap. Been around for a long time. Grass that happens to look like wood. Just a thought.
Cheers John.

Yes it could work ok, but it won't quite go aesthetically with the rest of the build. Besides, bamboo is quite springy and it would need to be a large size to have the strength. Also, I need to drill it to fit it to the pontoons and the yak, which will make it prone to splitting unless it is strengthened alot. Not practical I'm afraid for my application.

I'd do something with laminated layers for more strength.

Yes Matt, did you read my earlier question re laminating a cross beam?

3" should be more than enough. I do recommend the laminating be 3 separate layers.

It's been a few weeks since I have been able to get to my project. It's been wet and cold, I got sick with the 'flu, and before that I had to paint the house some more (I am going to hire a painter if I ever need to paint the house again!!!)

But tonight I finished sanding the first pontoon ready for laying the glass. I am very happy with how it looks. It seems very strong and the bolts are very strong and rigid. The second one isn't far behind, so I should be able to get to the business end of glassing and finishing in the next couple of weeks.


The under-deck reinforcing with the holes drilled for the bolts. I part filled the larger holes before installing the bolts, and filled over the top, then glued the backing plate to the deck plate.


The deck plate ready for fitting to the hull.


I knew I would find a use for those spare paving bricks one day!


Pontoon #1 finished 'nude'.

Good to see some progress there Steve. I was beginning to wonder what had happened to you but the weather and the painting are both things I can relate to at the moment .

They should look pretty good when finished. How heavy are they at present?

I haven't weighed them but probably about 2.5 kgs each max. That's not glassed, so maybe 3 kg when all done. I don't think that's too bad for my first effort. I have been

I have been thinking about you lately Bob, don't be surprised if I give you a call when I get into the major build. I can foresee some moments when a bit of an experienced eye and an extra hand might come in handy.