New Renderings

I’ve finally got some more current renderings, which show what I have in mind for my boat. It’s still a work in progress, and there are still a lot of details to work out, but it’s getting there! I’ve put a lot of work into thinking over the size and underwater shape of the hull, how to best mount the beams onto the main hull, and also what the coachroof and companionway is going to look like. I’ve also worked out a scheme to (hopefully) keep condensation on the cabin walls from becoming a major problem in cold weather.

The overall size of the boat is back up to just under 9 meters, I’ve finally figured out a way that I can build the boat with the available space (garage), and also how to keep the costs down enough so that I can actually pull this off. My estimate is that I need another 8000€ to complete it, from where I am now (tools bought, ama built, and some raw materials already on hand), so I’m going to have to work quiet a bit to get it all together. 😉

It’s good to be moving forward again!

— Marco

Back at it Again: a Mock-Up

It’s been a while since my last post, exams and a few other things kept me busy, but I’ve still been working on the design now and again. Over the last few days I’ve really gotten back to boat-design and actually building something again! Today I built a quick 1:1 mock-up of the middle 1.5m of the cabin, to check on the ergonomics of the current design. That was my third mock-up overall, and I got it done in just over three hours, which is incredibly quick considering that the first one I ever built took more than three days. I’m getting faster at this prototyping business. 😉 You can definitely trade a lot of the accuracy for flat out construction speed, and there’s plenty of tricks to help speed things along as well.

Continue reading Back at it Again: a Mock-Up

Tepukei-Style: An Accomodation Pod?

I’ve been looking at another approach to try and reduce costs. The idea is to have a long hull, but with comparatively low freeboard, and sealed off, like a beachcat. Overall, a lot like the Tepukei.

The intricate connecting structure and the sealed deck are characteristic of the Tepukei.
The intricate connecting structure and the sealed deck are characteristic of the Tepukei.

I’d build an accomodation pod ontop of that, out of relatively cheap polyerathane foam and fiberglass, and mount that between the hulls. It has a well-protected opening to the leeward side.

The hull is 9 meters long with 60cm freeboard most of the way. The pod itself is 2.8m by 1.2m and 70cm high. It has a 65cm overhang to leeward, to provide a very sheltered seating position outside. One thing it definitely does need however, is the ability to walk to the ama, fore-and-aft of the accommodation pod, so that definitely needs to be changed. I also don’t quite know yet where/how to step the mast on such a design.

While the accommodations are much more minimalist, I think it does have clear advantages where insulation and moisture is concerned. With a cabin in the hull, water will always tend to seep down through the hatch, and condensation on the walls is a major issue. A well-insulated accommodation pod doesn’t suffer from these problems, and the boat as a whole is way easier to build and a fair bit cheaper. Going around the Baltic in that, seems pretty daunting, but maybe with a bit of work, this can actually be made into a viable concept! 🙂

— Marco

Lightweight 8m Design

I grew a bit concerned with the lack of seaworthiness of a possible 6m design and aimed for something smaller with removable bow sections so it would be build-able in a garage. The interior of this boat would be extremely cramped, but even so, reducing the length to something on the order of 7.5 meters is still on my mind. I think it’ll be time to build another cabin mockup soon! 😉

Going Even Smaller?

I made a few changes to the parametric model of the hull, and then had the computer spend a couple of hours doing an optimization over a very board range of parameters. My goal was to find an even shorter hull capable of carrying the required load. The length-to-width ratio of the hull started coming down, the draft was increased slightly, and I ended up with a 6 meter hull capable of supporting 700 kilograms, which would be adequate for single-handed coastal hopping.

I also went through the mass and cost numbers for the boat. My best estimate is about 5000€ to get this boat ready to go (since I already have the ama built and quite a lot of epoxy in storage). Ontop of the cost of the boat, there is the potential cost of a workshop, which provided I can actually find one sufficiently close to me for regular work, would cost on the order of 100-150€ a month. Over say 18 months that adds up to another 2000-3000€. Looking at the ~9000€ needed to complete a 9.2m boat, that would make for a cost of 12000€. That is a sum of money which I absolutely do not have, and couldn’t even come close to racking up with a student job on the side.. The 6m boat on the other hand could be built in my garage, by building the middle 5.5 meters of it and gluing or bolting on two 25cm end-pieces, right at the end.

Figuring out how to support the rig on such a tiny hull proved tricky, but of the 4 available options, a supporting strut on the windward side, is the easiest to build and to operate. KISS. An even simpler and cheaper solution would a traditional Polynesian crab claw rig, but reefing is a bit of an issue, and with a lofty Hobie 16 mast I can get a heck of a lot more sail area on the boat than with a single crab claw sail. I’m going to need a bowsprit for that gennaker though… 🙂

Giving up loads of interior space and comfort doesn’t bother me so much, but with the reduction in length you take a massive loss in seaworthiness. While the maximum speeds of either design probably would not be that far apart, the average speed of the boat will also suffer significantly, even more so because the average number of hours where the boat is moving forward will also be less, on account of more in-port days (heavy weather) and I figure getting such a small boat to sail by itself under autopilot would likely be quite a challenge, at this size it’s more of a beach-catamaran than anything else. All that said, there’d be little sense in trying to build a boat I can’t afford, and if anything, the smaller boat would promise a real adventure!


Building a voyaging proa on a student's budget