Sailing faster

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Sailfree

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When being taught to race Dinghy's Mike Mac always said ease , ease, ease to go faster.

Now on big boats and with a speed log I am finding the fastest speed is when I feel slightly oversheeted.

Is it a difference between dinghy's (to keep them upright) and keel boats or have I missed something?
 
I was always also taught that when sailing dinghies and I apply the sam principle with my cruiser and I think it works. My mate always oversheets and I used to sail rings round him when we had similar boats, and I always reefed earlier and also went much faster.
 
When you say "when I feel slightly oversheeted." do you mean heeling a lot, or oversheeted with respect to the tell-tales? Many modern yachts will heel a long way before it slows them down much. Older designs often benefit from increased waterline length when heeled.
It also depends if you are trying to get to windward. The speed/height tradeoff varies from boat to boat, with crew weight and windstrength.
You can go too far in either direction. Either good instruments or a bit of one design racing will help find the best compromise.
In my current dinghy it is thought fast upwind to play the sheet alot rather than steer up in gusts. You would need a very fit crew to do this to the same extent on a 40ft yacht.
Also a lot of yachts have vangs/kicker that are not as powerful in proportion to their dinghy counterpart, so you have to use the mainsheet more for leach tension, which you may percieve as oversheeting, particularly the lower part of the sail.
Keep experimenting and watch the VMG!
 
[ QUOTE ]

You can try over or undersheeting, but correct trim is correct trim...



[/ QUOTE ]

That is the point I am alluding to. Correct trim on a dinghy seems more eased to me than correct sail trim on a keel boat.

Need to get back and do some more dinghy sailing this year.
 
Its very difficult to tell without seeing it. You may be oversheeting to counter an excessively baggy sail, or your mast may have too much rake making the sail shape wrong and you are trying to correct this using the mainsheet.
Additionally, are you using the same type of sail (fully battened, semi battened, furling?)

Ultimately you should sail to your tell-tales - if you don't have any then get some stuck on (on the front 3rd of the sail and the leach).

Jonny
 
Possibly, never thought about it before but could be the case if you try to sail a keel boat in the same way that a dinghy needs to be sailed. Most dinghies have planing hull forms which are designed to sail fastest upright. Because they are light and sensitive to sheeting position to keep on the boil the old saying 'when it doubt - let it out' means that you should constantly ease the sheets and sheet in to keep the sails at their optimum angle of attack. Keel boats on the other hand are designed to sail at their optimum with a degree of heel. The hull shape is designed so that the maximum immersed waterline length is at around 10-15 degrees of heel. Their mass and inertia means that they are less sensitive to the constant variations in wind speed and direction and constant tweaking of the sheets in the way that is best for a dinghy may well result in slower progress.
 
It depends entirely on the boat design.

I used to own and race a 707 and on those you oversheeted the main to the extent of stalling the head. Why? Cause the loss from stalling the head a bit was made up for by decent forestay tension created by the main sheet and the opening of the slot.

Before that I had a twin trapeze skiff and on that you could not oversheet the jib at all, because the slot got killed.

Point is that every boat is different. The only way to know is to sail against a similar boat and try out different trim to see what's the right combo for your hull and rig.
 
Another major difference between dinghies and keel boats is that dinghies can plane or at least increase their speed beyond water line length limitations more easily than a heavy keel boat.
This means that at higher speds efforts to get more speed are less rewarding in a keel boat than a dinghy. However efforts to sail closer to the wind are rewarding in a keel boat. So it can be better to pursue pointing rather than speed unless you are way below hull length speed limitation.
In ther words when on the wind once you havee reached a reasonable speed concentrate more on pointing.

Also in a keel boat if you heel the boat then inevitably you get a weather helm. This requires correction with the rudder which causes drag. So at some point the losses from leeway and rudder drag when heeling exceed those gains by sailing the boat hard with heel. So less sail or looser is better.

We tend to sail a keel boat to the average wind so when hit by a gust a combination of luffing up and easing mainsheet I find is the best way to handle the gust. If you rely on luffing or luff too much there is the great danger of being put about. If you rely on easing the mainsheet then you may miss out on some lift to windward and even more important a wind shift that is in fact a lift.

So very much in racing the boat goes faster to windward with more concentration on the part of the helmsman and more effort put in by helmsman and crew. This especially so at the end of a race when you are tired.
Lastly when racing never under estimate the drag of weed on the hull. That is a speed killer. good luck olewill
 
You are measuring speed using the log, and that has only an indirect relationship to the VMG towards the mark. So you may well be going faster on the log but slipping sideways all the time because you are oversheeted and actual;ly getting to your objective slower.

As people have already said, one way to judge is to race against similar boats and see how you do. The other is to set a reasonable mark in your gps as a waypoint and then try various sail settings reading off the vmg.

There is no reason why a cruiser should be different in principle from a dinghy - getting max power from your all white sails is the same in both cases, and all to do with the position of max draught and laminar airflow etc. But achieving that situation in any particular hull results in differing angles of heel and differing ratios of forward to sideways movement. So you have to back off from the ideal sail trim to some degree to get the best performance through the water. And cruisers are almost always more compromised than dinghies whose main design objective is usually performance not accomodation.
 
Another differentiator between dinghy & yacht that's not been mentioned yet is wind shear, where the apparent wind direction at the masthead is different from deck level. It usually manifests itself by not being able to get the top leach telltale to settle with the lower ones. We found it happenned a lot on our (then) 33 ft fractional rig.
 
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