Mini Ocean Racing Scow

[ancient kayaker]

Doug: it still looks closer to spherical to me than any other bow I have seen. As the boat heels it looks like the wetted surface is reduced and the lines become narrower, more like a canoe, perhaps providing a similar drag reduction benefit to a heeled multihull. I believe a flat-bottomed sharpie hull behaves similarly; but that's only conjecture.

 

[Doug Lord]

747 Scow

Doug: it still looks closer to spherical to me than any other bow I have seen. As the boat heels it looks like the wetted surface is reduced and the lines become narrower, more like a canoe, perhaps providing a similar drag reduction benefit to a heeled multihull. I believe a flat-bottomed sharpie hull behaves similarly; but that's only conjecture.

====================
I agree with your conclusions-I just can't really see what I'd call "spherical"-
but no matter: its an incredible design.

 

[sharpii2]

A round-bilged scow seems to have a number of advantages, extra forward buoyancy allows it to a press of sail, it maintains neutral helm when heeled, and it has more hull volume and deck space.

Does it have any disadvantages compared with a hull with a conventionally shaped bow, or is it’s lack of popularity just because people think it doesn’t look like a proper boat?

A garvey would be be similar I imagine and easier to build but - other than in dinghy size - might have less manners in a blow. I haven’t sailed either typs but am interseted in more informed opinions.

The main disadvantage is going up wind in a chop. Nothing like having a meat cleaver bow to slice through those rollers, instead of slamming into them.

This is the main reason a scow is not considered all that seaworthy.

This boat is really more pram-like in its plan form.

Prams are a compromise between a scow and a sharp bowed boat. They are popular as boat's dinghies as they tend to be shorter for a given amount of displacement and are easier to stow.

In the case of a mini, the pram like hull has more bearing area forward and planes easier. It also has more initial stability (more sail carrying capability).

Even with the same sail area, it can be faster down wind. It can carry its sail in stronger winds, and, since the bow rocker tends to force the bow up, it is less likely to bury its bow and broach.

 

[ancient kayaker]

Makes sense Bob - thanks.

 

[Gary Baigent]

Paul Whiting and Murray Ross used to say about their Half and One ton designs, that the hull began planing right from the bow; see lines drawing ... and that was back in the late 1970's.

 

[Doug Lord]

747 Scow

Raison is now 96 miles ahead of second place and 148 ahead of third.

UPDATE 10/29/11: as of this post David is 118 miles ahead of second and 148 miles ahead of third. 255 miles left-speed around 6 knots. 37 hours.

http://tracking.transat650.net/carte/etape-2.html

 

[Doug Lord]

747 Scow

David is less that 12 miles from the finish and doing 9 knots! He will win!
Congratulations David Raison!

http://www.charentemaritime-bahia.transat650.net/en/

Great pictures of a smiling David Raison: http://www.charentemaritime-bahia.transat650.net/en/media/photo.html

 

[Doug Lord]

Will this boat be the next breakthru?

Picture: built by Isotop, designed by Hugh Welbourn, the first DSS equipped mini. Much narrower boat than a "normal" mini. May have close to the RM of the Scow with the retractable foil deployed---

 

[Doug Lord]

747 Scow

From the race website tonight: http://www.charentemaritime-bahia.transat650.net/en/news/939/raison-wins-in-bahia.html

A jubilant David Raison sailed past the comitee boat shortly before 8.00 pm tonite to take line honors and win the 2011 Charente Maritime/Bahia Transat 6,50. His sailing time along the 3 120 milles course is 17 days, 6 hours, 13 minutes and 32 seconds, at an average speed of 7,53 knots. He beats Yves le Blévec record time on this specific leg by 23 minutes. His overall time on both legs of the race is 26 days, 3 hours, 9 minutes and 40 seconds, at an average speed of 6,80 knots.

Quotes : "This is my fourth try on this race. I come out a winner, and in full day light. Its been a tough one, for me and for every one else. Yes, I've had my doubts, when I was ahead by a hundred miles and hit a windless spot.I thought everybody was passing me. Some other time I had to step on the brakes real hard when the boat was slamming away, and yet, I was gaining on everybody.
Yes indeed I have the feeling that my boat is like a kick in a bees nest of naval designers. The question is wether or not we'll see 60 footers based on my design. This I do not know. There 's so much to study.
All along the race I've tried to follow the advice a former "Minist" once told me : Rigor and discipline. Then you get the job done! But what a joy to be here and to see you all! This has been the toughest race of all.

click on image:

 

[Doug Lord]

Mini Scow lookalike sorta

A design by Uffa Fox I found on the front page of SA. A Mini mini scow sorta.
The Dyer Dhow I learned to sail in was sorta like that forward except a bit more chine.

click on image: (lower pix Dyer Dhow)

 

[Gina_S22]

Hi Doug Lord!

My oppinion DSS is illegal in Mini Rules:

J-2-b Maximum beam: 3 metres including mobile keel(s), rudders, daggerboard(s) and mobile mast(s) (including spreaders) regardless their position, boat maintained without heel.

The wing max width is 3 m.

 

[Doug Lord]

Mini DSS

Hi,Gina, I don't know the dimensions of the Isotop boat but lets just say it is 5'
(1.52m) wide or so. That leaves 4.85'(1.48m) for the retractable foil.
And one other thing: Hugh Welbourn is a well respected and competent designer-he would not have designed a boat that used the foil w/o being sure that it would measure in.

 

[Gina_S22]

Thanks

 

[peterchech]

So the boat would be narrower on the beam to accomodate the foils? Faster upwind maybe, but wouldn't you be losing planing area in this mostly downwind race?

 

[Doug Lord]

Mini DSS

So the boat would be narrower on the beam to accomodate the foils? Faster upwind maybe, but wouldn't you be losing planing area in this mostly downwind race?

==============
Peter, the enormous lift provided by the board would reduce the required planing area as well.