A Cute Little Proa

I spent about 4 hours today drafting a fresh design from scratch, to look into the possibilities of a much smaller design. I love how enormous the rig looks on that little boat, and I think she came out really cute! 😉


As it stands, my 9.2m design would cost around 9000€ and 600-800 hours of construction time to complete (with the ama already nearly done). I don’t have anywhere near to that amount of money. This much smaller design would take way less than that, and would be much cheaper in its upkeep as well. If I could keep condensation and moisture in the tiny cabin under control, then even this boat might be enough for a solo run around the Baltic. Here are the specs of this design:

specs

The underwater design is machine-optimized using the Galapagos evolutionary solver, which comes as part of the Grasshopper plugin for parametric modelling in Rhino. I spent quite a lot of time building a parametric model for proa hulls, and incorporating a couple of nice tricks, but now that I have it set up it’s amazing how good the numbers on these machine-optimized hulls turn out. I’d probably need another couple of hours to update the loading list and do the mass estimates for this design, but that’s for another time. 🙂

Cheers!
–Marco

 

Aboard the Dragonfly (pt. 2)

As it turned out, the conditions on Thursday, the 7th of April, were far heavier than anticipated. Shortly before we decided to head back to port, we saw 32 knots on the wind instruments. We were up against pretty steep 1.5m sea, despite deliberately having chosen a route which was just 2-3 miles leeward of the coast, and with good water depth. Having motorsailed out of Middelfart with the jib, we had the headsail up. In those conditions we would probably have needed no jib at all and the mainsail in its second reef. Due to a jammed roller we’d have to tie in the 2nd reef manually though, which would have been problematic to say the least, in those conditions.

Under jib alone, the center of effort was way too far forward, and as a result could make only very limited progress to windward. After driving the bow through a wave, the anchor locker was flooded, and we were concerned about the locker’s hatch being damaged if we did that a few more times. Further along our route, we’d have been in much more open water, where the wind and the seastate likely would have been heavier still, so Daniel decided that discretion is the better part of valor, and we headed back to Middelfart once more. It was the right call to make. Heading back, was like any afternoon sail, with the wind and waves form behind, things were pretty relaxed and we made port shortly thereafter.


The rest of the day we just hung around and had a relaxed day in port. On a side note, I’d taken seasickness tablets (50mg dimenhydrinate) twice the day before, and once that morning (and they really worked), but despite being far below the maximum recommended daily dose, I really felt their side-effects that afternoon. Common side effects (>10% of cases) include sleepiness and muscle fatigue, and while I had a bit of that the day before, I wasn’t of any use when we docked that day, I was just lethargic to the point of not wanting to even move anymore. On top of that I was feeling down and a bit depressed, and ended up wandering off on my own for well over an hour, to try and clear my head a bit. I certainly recognized that gloomy state of mind from many years ago, but I couldn’t really understand why I suddenly felt that way again, and why I was having such a hard time working my way back to a positive mindset. Later that afternoon I read through the list of side-effects: depressive mood, in 1-10% of cases… Go figure… A few hours later I was right as rain again. It’s certainly something to take note of for the future though!

The next day we got up, and looking at the wind we knew that all of our efforts of that week were going to be royally rewarded! 🙂 On Friday we had perfect sailing conditions with 10-20 knots of wind at a true wind angle of 90-110° for most of the day. We never sailed higher than 60° or lower than 120° TWA, despite threading our way through several islands and channels. We had waves on the beam or on the stern the entire time, and even had as much as a knot of favorable current at times. That day we sailed 63 miles in just under 10 hours, without jibing or tacking once. That was pretty neat!

Overall I learned a tremendous amount on this trip, especially about the interior layout of a 9 meter boat, which is knowledge I’ve been busy applying to my own design, since I got back. I think Daniel, who intends to circumnavigate the Baltic Sea in his boat this summer, has picked a great vessel for the job, and I think he’s got a great experience infront of him. I’m really thankful to have had the opportunity to sail with him and Hilke so early in the season, and I’m eager as ever to get out there on my own boat!

Cheers,
— Marco

Aboard the Dragonfly (pt. 1)

Recently Daniel and Hilke, two friends of mine, bought a Larsen 28. It was stationed in Hobro, Denmark, and they asked me if I wanted to come along to get the boat from there to Kiel in Germany, its new home port. Despite some concern over the low air and water temperatures at this time of year, it was an offer I was happy to accept. A little after noon on Thursday the 31st of March, the train roared out of the station, carrying me toward Eckernförde in northern Germany. It’s Hilke’s home town, and after rendezvousing there and loading all the gear and ourselves into a larger car, we headed for Hobro on the morning of the 1st of April. I’m sad to admit I didn’t get up to any mischief this year, but the trip went smoothly and we proceeded to clean and do some repairs on the boat, as well as loading it up and getting it ready for craning. It was in the water Saturday evening, and after some final preparations and a test sail, we headed off on Sunday afternoon.

It was sailing upwind in light air, which was a good start to get to know the boat a boat. With a bit of motoring, we made it from Hobro to Hadsund by nightfall. In the following days we sailed to Grenaa, Hou, Middelfart, Middelfart (again), Damp, and finally Kiel. Conditions started off with light air upwind sailing, with the wind increasing significantly over the course of the week. On the leg from Wednesday Hoi to Middelfart we sailed upwind in 13-18 knots for most of the day, but encountered sustained winds over 20 knots later on, which hindered us from continuing under sail. The boat doesn’t have any storm sails yet, and the jib with a double reefed main proved too much when sailing to weather. Thursday morning was peaceful, and with the same forecast as the day before, but better shelter from land and deeper water, we felt pretty optimistic about the day.

 

I even took a few minutes of video, reflecting on the trip so far, and looking forward to another day’s sailing.

— Little did we know just what we were heading into…

Something is Cooking…

I’ve been busy the last few days, with preparations and shopping. Oriented strand board (OSB) is not a boatbuilding material, but can anyone guess what I might be up to? 🙂

A Brief CAD Session

With exams coming up, I certainly have more pressing matters to attend to, but I decided to do a bit of CAD today anyway. For the last few months I’ve been working on a genetic algorithm to help optimize the underwater shape of the hull, so it’s been ages since I last did any modelling work. My overall design concept has changed quite a bit over the last few months though. I’ve been doing a bit of reading, a lot of thinking, and I had the opportunity to visit the ‘Boot’ trade fair in Düsseldorf last weekend, where I got to see a few high performance catamarans and trimarans up close. All those accumulated ideas on paper, had me itching to finally do some CAD work again. 🙂 I started from scratch, and in a little over three hours I created a model which incorporates several of those ideas and influences.

While this is more of a ‘rough sketch’ than a real design model, it was a good opportunity to try out the new dimensions (9m long), a new waterplane shape (using a cubic bezier curve) and a new deck design using conical sections. I’m happy with the way it turned out! While this bow is very fine (with an opening half-angle of only 8°), it’s probably one of the most voluminous bows I’ve ever drawn for that angle, which is a really good thing.

Somewhere down the road I’ll do a proper version of this design. At present the bottom of the beams are only 50cm above the waterline for instance, which is way too low, they need to be at least 10-20cm higher up, to avoid being driven through waves. Arched beams could be one way to resolve that issue. I might give the boat a little bit more freeboard as well (it’s only 70cm at the moment), the hull will also get full length spray rails to make it a bit drier, and possibly even a knuckle, to make the boat a little wider above the waterline. All in all though, I’m optimistic that this will make a very neat design in the end!

Cheers,
Marco

Building a voyaging proa on a student's budget