The Laser boom wasn’t designed to be loaded from the mid-boom position and even the small portion of sheeting load that was redirected through the mid-boom block (which was only affixed with a couple of rivets anyways) would cause a rather disconcerting bend in the spar.  I can remember using the “super-vanging” technique that was popular on the race course in those days and cringing… waiting for the whole thing to come apart.

Your proa will also have a much greater righting moment than a Laser, so the rigging loads are potentially much higher as well.  Maybe use an additional fiddle block on a strop routed around the boom and through the clew cringle (like the stock tie-down) for the second sheet?  You could do something similar at the turning block at the mid-point as well if you prefer that sheeting location, right?

Hmmm, good point about sheet loading. Thanks. I’ll have to make some drawings. I’ve never sailed a Laser in more than 10 knots, and my Siren with mid-boom sheeting has a stout boom, so I’ve never seen one bend.
Hitting the road in about 3 hours…

Happy New Year! I’m back to building.

I’ve glued together 4 hatch frames cut on the table saw and miter saw, and although I’ll rasp, grind and glue them into submission (and water tightness), in hindsight it would be much better to cut the frames from single pieces of plywood and router the gasket groove - like in PT Watercraft’s kits.

I glued together one side panel for the cockpit. The taped side of the butt joint needs at least one more coat of glue to hide the tape’s weave.

Next steps are to build the other cockpit side, finish the hatch frames and glue them to the cockpit floor, and then it’s hull assembly time.

Time: 40.5 hours

A change of plans: the build will go much more slowly for a few months because I took a second job. Also, my wife persuaded me that it would be best to wait for warmer weather before making the hull 3D, since it would be bad to paint it in the house, and it needs to be stored outside. That made sense to me.

For now, I’m finishing up the cockpit hatches, and then I’ll start building more frames toward the ends of the vaka.

I’ve also been thinking that it would be easier to make the quarter rudders so they can rotate through 270 degrees. That way I can just use Laser dagger boards as blades in the Dierking-style cassettes, and flip them around during shunts. The rudders will need to be push-pull, but that’s fine. If I want to make ogive section dagger boards later, I can just drop them in, and then I won’t have to flip the rudders when shunting.

Build time: about 45 hours so far…

I’ve drawn all the frames for the vaka on plywood, and I’m waiting for a nice dry day to cut them out.

I figured out how to assemble the frame sandwiches that each hold a mast tube and an aka support. Each sandwich consists of 4 plywood frames 10cm apart with timber between. The mast tube sits between the first two frames and the aka support sits between the last two, and the middle two are spaced apart to get the positions of he mast and aka where I want them in the hull. These sandwiches have to withstand the greatest forces on the boat, so I will probably over-build them.

I also sketched a design for a canted quarter rudder using a Laser dagger board. This is a push-pull rudder that must be rotated 180 degrees on each shunt. Since the Laser dagger board is designed for a shallow slot (maybe 20cm), the housing will need to provide clearance for the ‘handle’ at the top of the dagger board to be pushed in quite far. I’m hoping that angling the board forward will reduce cavitation. What is a good angle? The Dierking cassette allows even a canted rudder to kick up. I think I might need to line the inside of the rudder housing with neoprene to stop the rudder from climbing up over time. The rudder post will extend through the top plank and rise above deck level so the side tiller arm can rotate freely.

Build time: 49.5h, but the main hull is not half done. Oh, well!

Early this morning, it occurred to me that it would not be much work to lower the akas to below deck level, because of the way I designed the bulkheads and framing in that area. So, the question is should I? As designed, the platform between the akas will be 70 to 80cm above the waterline.

If I were to lower it 15cm, it would reduce windage, and the sheeting could be simplified, but the aka platform would be awash more often. The slots where the akas meet the vaka might trap water and promote rot.

Thoughts?

Very slow progress - everything trumps boat building. But I am really enjoying the few minutes I spend on the forums, and all the proa concepts and builds presented.

But I have made some progress. I’ve decided not to lower the akas, since that is easier.

I’m working on the big frames under the aka mounts and around the mast tubes. An aka support frame and a mast tube frame will be bolted together through timber to form a rigid box. The plan is to transfer most of the mast forces to the akas, so the rest of the vaka can be built lightly. But I’d rather it was sturdy and a little heavy.

Also, I found a piece of 8” PVC pipe for my ama. I’m trying to find cheap pieces of 1/4” PVC sheet to weld to the ends. If not, I’ll glue in thick MDO instead. I want to not worry about running the ama over stones and barnacles, which are much more plentiful than sandy beaches in BC. PVC is great for that, although it’s a bit heavy.

Looking good. I kind of wish I had kept a log of how long my build is taking, I’m sure it is probably about double my guestimate! Have you got a plan posted somewhere?

I’m a bit confused by your quarter rudder. Are the two planks on the diagram attached to the side of the hull? If so, are you not worried about the lower one being below water level? It seems like a lot of drag.

If you do a search on Gary Dierkings blog you’ll find some good stuff on PVC amas. I just finished mine today, used a heat gun to shape the ends. Not a recommended technique!

-Thomas

Thanks Thomas. I’d like to find out how your proa performs.

No, I haven’t posted a plan. I designed the hull in hullform, from which I got a table of offsets, but I never figured out how to export the renderings. I have some crude sketches, but I’m too lazy to redraw the whole thing when I change my mind about something. I just make a small sketch and notes, like for the rudder. I built a model of a 7.2m proa a while back (photos in another thread), and this one is similar, except no hard cabin top, and the hull is in sections that bolt together, like Wa’apa.

I’ve designed the bottom plank holding the rudder post to be about 10cm above the water line, but I’m sure it will cause drag in waves. I want the boat to be easily beachable, and able to run hard aground without anything more than scratches. The kickup rudders will permit that. I don’t have confidence that Newick-style rudders would survive repeated abuse. Quarter rudders are easy to build, and I can use Laser dagger boards for blades. I’ll live with more spray and drag. At least, that’s the plan.

I’ll look over Gary’s PVC ama info. I plan to just make long diagonal cuts at the ends of my pipe, to fashion scow bows. I’ll fasten a flat piece of something to fill in each long elliptical hole. I don’t want to experiment with forming PVC, since I’d need a lot of heat with this thick pipe. If I can find sheet PVC, I know a guy who can weld it. I’d like to minimize my dioxin exposure. :o)

I like Gary Dierking’s PVC ama method - but I’m not sure I want to use epoxy. We’ll see…

I mostly assembled the first mast tube bulkhead. I still need to attach plywood to the open face, and then 1x4 braces across the top and bottom of the mast tube. The tube is just ABS drain pipe with an end cap at the bottom and a collar at the top. I think I’ll fill the cavity around the mast tube with urethane foam to keep water out.

Time: 76 hours

I’m still building frames. No idea when the hull will become 3D. Thanks to all the other proanauts who share their dreams and ideas - you keep me going. I think I may call my proa ‘the ark’ instead of EZZE…

I’m assembling the centre section of the vaka - finally. I hope to have it assembled and painted within a week. So far, so good - only a little chiseling and cutting. I want to tape all seams around the cockpit floor before I flip the section over to measure and cut hull panels. My wife calls it the fuselage.

starting to look like a hull in 3d!

The center vaka section is almost finished, just some more painting.
I understand now that Titebond III does not make a good gap filler, but Titebond + sawdust works OK. I wasted several days slowly filling gaps when I could have done it in one go had I made paste with sawdust.
My wife is also teaching me the art of painting. Definitely a workboat finish.

That’s a nice dog house 😉

When on the water no-one notices a rough finish from shore. Looks great!

Thomas