Dinghy Development

Originally posted by RS400atC But when it comes to inertia in a dinghy, take say an RS 400 weighing about 130kg ready to sail, most of us are going to be adding around the same again in body weight. So even if you could halve the boat weight, you'd only lose 25% of the inertia. But for the same length you'd make less waves and have less drag the whole time you were moving. Most classes have a minimum weight for a very good reason!

About 6 years ago I volunteered to crew one race for Andrew Leigh at Burghfield Sailing Club in his RS400.

I am not the most petite of people and at the time i was 6ft5 (still am) and weighed a couple of pounds under 20 stone in weight. Andrew was exactly the same. Our all up crew weight was just under 40 stone or 250ish kgs and combined height 12ft10.

I can confirm that the boat did not accelerate very fast and going up wind the pole was just clear of the water!

Going downwind in quite a blow with the kite up we were planing but you could literally see a ditch in the water behind us.

Thanks mainly to Andrew's sailing skill we did not come last and despite our weight we were faster downwind than some others as we were able to power thru where others feathered tho it is a miracle that nothing broke.

An observation was that with our 40 stone gybing an RS400 gave you the impression of the stability of an aircraft carrier. It was a great experience tho not one I expect to repeat any time soon even if I have lost a couple of stone.

You can't seem to make dinghies down to any sort of sensible weight, 18 kgs is heavy ffs where I come from, so don't ever think you could make them light enough even if you did build the hull out of unobtainium or that new stuff, forget what it's called, a replacement for carbon that just got developed, your damn sails are so heavy and the masts are mostly jokes, who was it said the Finn mast was technical, shut up, they are that way because they have to support most of you lard boys and your great bulk sitting there displacing far to much space.

The reason I wanted it light is just simply the launch and recovery drag, never mind the performance boost, not sure about solid rigs either, they seem OK in high apparent wind, but where we dwell, they don't seem to deliver the low end torque, I'm going to find that out shortly if my soft version of exactly the same sail does deliver the early acceleration either off the line or after a transition I'm looking for at the moment for my lake and puddling dwelling, if I sit on top of someone out of the line I expect them to stay sat on and not sail out from under me.

Oh, I'm back by the way, I can see you've missed me, slipping back to your normal ways of talking total bollox.

Edited by iGRF - 06 Feb 13 at 2:31pm

You just have to look at the boost in performance of Sail Rocket to see that wings are more efficient in certain conditions, and the wing masted C class cats benifit because class rules only allow 300sq ft of sail/mast on a 25 foot boat, so they need all the efficiency they can get.

But, a monohull on a small pond? I don't think the efficiency of the rig is the deciding factor on speed.

Originally posted by iGRF You can't seem to make dinghies down to any sort of sensible weight, 18 kgs is heavy ffs where I come from, so don't ever think you could make them light enough even if you did build the hull out of unobtainium or that new stuff, forget what it's called, a replacement for carbon that just got developed, your damn sails are so heavy and the masts are mostly jokes, who was it said the Finn mast was technical, shut up, they are that way because they have to support most of you lard boys and your great bulk sitting there displacing far to much space. The reason I wanted it light is just simply the launch and recovery drag, never mind the performance boost, not sure about solid rigs either, they seem OK in high apparent wind, but where we dwell, they don't seem to deliver the low end torque, I'm going to find that out shortly if my soft version of exactly the same sail does deliver the early acceleration either off the line or after a transition I'm looking for at the moment for my lake and puddling dwelling, if I sit on top of someone out of the line I expect them to stay sat on and not sail out from under me. Oh, I'm back by the way, I can see you've missed me, slipping back to your normal ways of talking total bollox.

Ah Graeme, glad to be back?
It must be of great comfort to you that, should the bike/ board game slow down terminally, a long glittering career in international diplomacy awaits.

Anyhow, what does an f1 tub weigh? Ie all except engine and transmission, wheels and suspension? I don't know but I'd guess at least 100kg, one of them is tiny , loads smaller than your average boat. In any case they'd weigh a lot more than a snowboard / mountain bike.
Those boys would have us believe they know their onions, and are paid as such - they can't be wrong too can they?

Originally posted by RS400atC Originally posted by getafix Said it before, will say it again. The next big step in dinghy development is the roll-out of 'solid' wing rigs for dinghies. More efficient. Needs less replacing than flappy sails (in theory). Could be made modular so you can store them. You can put all kinds of hocum on why this will happen but the fact it's all over AC at present, it will 'trickle down' at some point and offer a real way forward in single, double and multiple crew dinghies and keel boats. Sails are just wings after all..... I'm not convinced. Solid wing rigs have been tried many times since the 60's, they had a spate of success in the Little America's Cup, but in most cases even wing masts have been found inferior. Several people have tried wing masts in Merlins I believe, where the area of the mast is a potentially welcome boost to sail area. Sails are more than wings, sails have to operate over a wide range on wind speeds, and most crucially, wind speed gradient, implying a need for a controllable amount of twist. Sails also have to be reversible to work on either tack. I'm not sure, the AC rules might well influence the choice of a wing rig? Weight is going to be a problem when scaling down to dinghy size I feel. Maybe it will trickle down via cats, but if you were designing a 15 or 16ft dinghy from a clean sheet of paper, could you make it faster in a range of conditions with a wing rig?

Good points. However, I think we're nearing the point where the technology (at a price) will meet the design capability and previously it was one or the other, but you couldn't have both.  Agree about the narrower wind band, but I think that by the time the technology arrives in dinghies to stay, the wings will be modular and therefore will be easily 'made' by the sailor prior to launching in order to suit the conditions.  A drifter will still be pretty boring for the speed junkies and likewise a howler will still have some looking for the bar while others are practically straining at the leash to get out there.

We know wing sails can be more efficient, I'm thinking that the convergence of technology at a price point (i.e. low weight carbon-fibre structures and films) with modern design (including trickle down) will make this the next big step in dinghy development