not for publication - need to cite sources

September 12, 2011

Sailing with Blind Date, a Harryproa Visionnary by Sven Stevens,

In the proa corner of the sailing community one is expectantly looking forward to a video of sailing with Blind Date, special after the latest rudder modifications. So last Sunday September 11 and together with four guests we sailed Blind Date special for this purpose. The wind was between S and SW and blowing force Bf4 to Bf5 (according to local weather station, our windmeter is in the repair), max GPS speed 12.8 kn.

ed. note: Bf4 to Bf5 = 13-19kn TWS so lets assume max windspeed 19knots

50’ Blind Date max boatspeed 12.9 maximum windspeed 19 knots boatspeed is 0.68 X windspeed
36’ JZERRO max boatspeed 17.8 maximum windspeed 12 knots boatspeed is 1.48 X windspeed

Now, Lets do that again for comparison sake; now with average windspeed instead of maximum

50’ Blind Date max boatspeed 9.5 average windspeed 16 knots boatspeed is 0.59 X windspeed
36’ JZERRO max boatspeed 16 average windspeed 12 knots boatspeed is 1.33 X windspeed

That is downright slow for a 50-footer.

We sailed from Flevo Marina Lelystad to Trintelhaven in the lee of the dyke Lelystad to Enkhuizen. That’s why the water is quite flat without significant waves. Click for the YouTube video.

My Ipad was loaded with a GPS tracker. Click in the pictures below to see the track and speed record. Another click in the then expanded picture brings you to the moving track in Google Earth.

ed. note: Below an inserted sample plot of Blind Date's recorded "high performance track" in the Netherlands. First outward bound ,next inward. NOT even making half the TWS doing so.

ed. note: Interestingly, near the end of the trip, Blind Date had to shunt to get back to the harbor, the angle of the shunt should have been about square on the old upwind track, yet Blind Date is sailing on an almost reverse course, after the next shunt they gave up and started the engine, obviously not fancying yet another shunt without making much VMG.

Also I quote a recent article about Blind Date:

Source: Catamaran and Trimaran Club, The Netherlands
Received: 20th December 2012
Author: Nol Twigt (translation by Sven Stevens)

Sailing a Harry Proa


The picture I had in mind was a futuristic boat of large dimensions. I had immediate doubts by the sailing characteristics. Going for and aft, what to think about that? We were used to Freya, a wadvogel 38 a multi chine marine plywood catamaran, with a small interior. [ Freya was formerly owned by Fredjan]

# 1 First encounter

When entering Blind Date's marina my previous impressions fitted the bill. Blind Date sure looked futuristic. The planview showed a platform of 50 x 27 feet, about twice Freja's platform. Then again Blind Date only weight about 2 tons ,half Freja's weight. The owner Jan Schipper told us he managed to get a different berth, because Blind Date was difficult to maneuver in an out of the harbour. This had to do with the rudder problems, as beam mounted in 2008, the original rudders were way too light. Unfortunately Blind Date performed very poorly with this new setup.

Fredjan and I investigated on the rudder setup in amazement, we saw square carbon tube 80mm x 80mm [ 80mm = 3.15"] which on the waterline turned into a 400 mm x 1500mm rudderblad [ 15.75" x 60"] , attached to rack and pinion, followed by cables to the steering wheels. Breaking pins should sort the grounding scenarios. We again looked at each other with raised eyebrows. At least for Dutch waters 3ft of rudder draft is rendered too much, sure to hit the rudders first, and the idea to float helplessly around, fiddling around trying to get a new breaking bolt installed didn't appeal to us, especially not with blind passengers aboard.

# 2 First sailing experience

We used a light Yamaha 9.9hp and Arka electric engine to get us out of the Flevo marina. When raising the sails Blind Date remained stationary at half wind, for a "normal sailboat" an awkward position, but ideal to stay in position ,Blind Date gives all the necessary time to raise the engine before sailing away. Once Blind Date started to move, Fredjan and I looked again with somewhat raised eyebrows to each other, What was happening here ? We expected on base of the huge length, less weight, and about the same sail area, to have more speed than our own 37.4 ft Freya cat. But it looked like the handbrake was still on. In a certain sense this was true, as both rudders were at a huge angle to prevent Blind Date's bow to turn into the wind. The boat barely made half wind, and as soon as the jib luffed the speed fell under 4.5 knots. The rudders than both stalled, and we had to put Blind Date to a full stop, drop the sheet, till the boat was half wind; next we had to grind in the sheet in order to let the jib fill first, to prevent the boat to pointing straight upwind again. This "half shunt" maneuver failed more often than it succeeded.

#3 Forces acting

Freya was balanced fantastically, 2 very small rudders with limited rudder angle made maneuvering the Wadvogel 38 cat easy to maneuver under all circumstances. I became curious where the difference in handling came from, and started to picture the forces acted on Blind Date. If you look at the whole setup of Blind Date, you immediately see that Rob Denney isn't afraid of big forces. The 17m mast turns in a needlebearing in the nearly frameless leehull [vaka].

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