For whoever is interested, here is the SketchUp file of my catamaran design. Please share if and when you have improvements!
Month: April 2017
3D catamaran design refinements
Here is the latest iteration of my catamaran design. I’m still not sure what I will do for cabin, but I guess I’ll figure that one out as I go along.
I’ve added some additional braces under the deck (the deck will be 18 mm). I’ll probably add a 45 degree panel from the underside of the deck to the side of the hull to make the entire structure more rigid.
Another change from previous designs is that I moved the front cross member forward, against the front bulkhead. This will increase cabin space dramatically. The net between the bows should make a nice place to sit and enjoy the water 🙂
Holes in the bulkheads
While driving home from work, I was thinking about how to secure stuff stored inside the hulls. What if I have some supplies, batteries and whatnot on board? I don’t want everything sliding back and forth while sailing. I need something to tie stuff to…
So I drilled some 5 cm holes in the bulkheads. This gives me something to attach a line to. Ideally I should also have attachment points along the length of the hull. Not sure how I should go about that. Suggestions are welcome!
This weekend the bottom of the first pontoon was closed and she could be turned upright. Another milestone 🙂
I’ve also started work on the second pontoon. The glued together sides are on the garage floor. Bulkheads are done already, so I should be able to start gluing her together next weekend. It’s going to be a crowded garage.
Next is filleting all the joints. It’s pretty hard to get epoxy thick enough so it doesn’t run. I need to add about 10% filler material, measured by weight (150 g of epoxy needs 15 g of filler). That makes it so thick it’s hard to mix. In the end I kust checked every few hours and smooth out any runners. Not perfect, but good enough for me.
I’ll put injection resin on the inside to make the wood waterproof. I may also paint the inside, haven’t decided on that yet.
A little step every day
After work I don’t have the time and energy to take on large projects. But i try to make a little progress every day. Yesterday I tweaked my design a bit in Sketchup, making the thing fit in my garage. Today it was making a second bottom piece:
Lets see what tomorrow brings 😉
Making some sawdust, finally
After lots of thinking and designing, the time has finally come to make some sawdust and see if I can actually make my ideas a reality.
This pile should be enough for both pontoons + parts of the middle deck. I’m not sure what to do with the cabin, so I’ll get wood when I get to that part.
Laying out and connecting the planking for the sides of the first pontoon. I made the connection with a simple butt join and glued a piece of plywood on top of the butt. Not the prettiest, but should be plenty strong for what I need.
Sawing the bulkheads sure makes a lot of dust. I cut bulkheads for both pontoons. Hope I got the numbers right 🙂
Just follow the plans…
I will round off the edges and add a few layers of glass later. Should do the job. The front section, up to the first bulkhead, will be sealed permanently for make an air tight chamber. I wonder if I should fill it with foam or something else? I will impregnate the wall inside and out with epoxy.
That actually went a lot easier than I expected. I dreaded having to adjust the curvature multiple times, but somehow it fit on the first try. Very happy with the results 🙂
…and back to catamaran
Just before I started building, I decided (more or less on a whim) to go back to my initial catamaran idea. I really like catamarans. They are inherently stable, don’t need ballast and look good too. So I tweaked my first designs and came up with this:
It’s going to be a sailing cat and it will have some sort of cabin, although I’m not entirely sure how I’m going to shape that.
LOA: 4.80 m (15.8 ft)
Beam: 2 m (6.5 ft)
Draft: 15 cm (6 inches)