First Sea-Trial

Last week we left Kiel for the first longer sail on Proasis. Our triangular test course brought us from Surendorf to Marstall (Denmark) to Schleimünde and back to Surendorf. The total distance of approx. 60nm took us two and a halve days due to very light winds (sometimes even no wind).

We spent the nights on anchor exploring places where almost no other vessel can go: Without leeboard and rudders Proasis has a draft of only 15 cm. This allows to anchor in knee-deep water.

On anchor in 30 cm deep water right next to a sand bank.

We are very happy with Proasis’s sailing characteristics. As soon as the wind is above 8 kn she’s easy cruising at 4-6 kn. Top speed at about 15 kn of wind was 8 kn. In lighter conditions she feels underpowered but thats not a surprise, the polytarp sail is only 13 sqm. We might get an assymetric spi in the future.

Wake at 7-8 kn.

The helm needs not much attention, the tiller is simply fixed in a certain position and the boat keeps on sailing on a steady course for hours.

The white line is our adjustable auto pilot.

Proasis sails upwind well at a tacking angle of 115° (could point higher but would loose speed). Thats not exactly where we want to be (100° would be nice) but a good starting point taking into account the cheap and wrinkly polytarp sail and the leeboard issues (see below).

Three upwind legs, the tacking angle can be estimated. Will be optimized in the future.

Shunting turned out to be a very simple and reliable maneuver (at least in winds up to 20 kn, havent tried in stronger winds yet). It never went wrong and can be done singlehanded without any issue. The Rudders are inverted almost automaticly by pulling one line for about 2 seconds.

Ready to shunt the sail. A video and detail explaination of the entire process will follow soon.

The most important downside of every shunting vessel is most likely jibing downwind. Instead of simply shifting the sail from one side to the other, a proa has to come upwind, perfom a shunt and bear away again. Compared to a simple jibe on a conventional yacht thats very slow but we take it as part of the game 🙂

Sailing intoo the Schlei mouth, thunderstorm ahead.

Living on proasis is quite comfortable for two. During the entire trial we never went ashore. Sailing, eating, sleeping and repeat.

Messy bunk, we need to optimize the interieur to keep things organized.

Despite our very pleasant sail, Proasis is not perfect yet. Following tasks are on our list for the next trial:

  • Leeboard: The foil shape is to thick causing lots of drag and poor performance. We have to make it thinner.
  • Mast: Needs some stiffening, we’ve observed to much flex.
  • Sail step: We have to reposition it sligthly further forward to improve the balance of the boat.
  • Interior design: We need more cupboards, hooks ect. to organize our stuff.
  • Electric installation: We have non yet. We plan to install a solar panel, battery, navigation light and charger for chart tablet.

4 thoughts on “First Sea-Trial”

  1. Looks like a good trip, thank you so much for giving details of how Proasis sails. I will be very interested to follow your experiences with the boat in cold, breezy, northern European waters.

    Do you think you may eventually eliminate the daggerboard? It seems that you have good efficient rudders and I would live in constant fear of grounding the board in shallow waters.

    1. Thanks!

      No for sure not. The hulls are designed for shallow draft, not for lateral surface. Without leeboard she points 15° less. The rudders are also no meant to act as leeboards, only one is down at a time.
      Grounding the board would only result in a stop, it’s to solid to break or damage anything.
      The key to a good proa is balance. We nailed it pretty well but need to make some small adjustments for perfect balance. Will keep you updated!

  2. VERY cool Drua! Congrats on a very cool design and build. It seems like a sibling to the Rob Denny cargo proa. How is Proasis different, besides the cabin?

    What is the length to beam ratio of the hulls? What is the payload?

    And of course everyone wants to know how fast…

    I’m interested in how it handles with so little rocker. How is steering? It seems like it would have a high prismatic–so little hobby horsing. Is that right?

    I wonder about pivoting lee boards. I have one on my Gary Dierking Wa’apa 16′ tacking outrigger canoe. I love them for the ability to dial in CLR to balance the boat on most points of sail. I even use them to help get through a tack. It would be fun to try them on your boat. For experimental purposes, at least, installing one on each hull would be cool–you could try all combinations.

    Lovely work, guys. Looking forward to seeing more.

    1. Hi Chris, Thank you very much!

      There are many differences to Robs design: Asymmetric hulls, rocker in the bows, traditional sail, different rudder setup (double kickup), lashed beams and so on. We trie to merge traditional with modern features to adapt the Micronesian way to our local conditions on the baltic sea.

      The Leeward hull is about 8.6 m long and 40 cm wide at waterline. That’s a ratio of 1:21.5. The ratio of the windward hull might be a little bit less. She has a displacement of 500 kg and can easy carry 500 more. If necessary and placed in the leeward hull more would be possible but we have not tested it yet.

      She’s most certainly not a race with that 15 sqm polytarp sail but a relaxed cruiser. At 20kn of true wind we’ve reached more than 10 kn, 7.5 kn upwind and 9 kn dead downwind. Detailed measurements will follow soon.

      Prismatic coefficient is very high indeed. That’s on purpose because on the baltic we often get very short and steep chop. A nightmare for hobby-horsing boats like small Wharram cats. Proasis does not pitch at all and her motions are very gentle. Steering is fine but we won’t win a slalom race (sharp turns are not her favorite). After all its not so critical because a proa never has to come about. I see it as advantage to have a hull that turns very slow because it gives you a lot of safety margin and time for shunting. We’ve never failed to shunt so far.

      We’ve abandoned the pivotal leeboard early in the design process because it gets difficult to control hat higher speeds (Rob Denney tried it in full scale). Proasis got a fixed leeboard on the inside of the hull (outside position would interfere with shunting).

      We will come up with some videos about all details and handling soon, so stay tuned and subscribe to our youtube channel 😉

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