Dart 15 Forums

nick wrote:

In light winds (less than force 2) sailing two up with jib. Is it quicker to goose wing and sail dead down wind or do you think it is quicker to reach and gybe?
Sametion one up one sail ?
In higher winds it pays to gybe but in the light stuff Im nor convinced.

Dartful Codger replied:

There is probably a mathematical answer to your question in a given wind strength at a given angle, but then wind is never that precise, as it constantly changes in force and direction, so sailing downwind is largely a case of 'feel', but also with more attention to burgee/windex information. Tell-tales are not too helpful on a broad reach, since they generally drop as the wind starts to behave differently across the sail.
The jib provides the 'slot' effect which improves the airflow across the mainsail, making it more efficient, so goose-winging removes this 'added benefit'. Also, given that a catamaran accelerates much more than a monohull when the wind increases, which then brings the 'apparent wind' more forward, it will always pay to go for speed IN A CAT - (not so in a monohull)
The trick is to judge how high or how low to go, and you can only work that out by constantly assessing your progress relative to boats around you, looking at your burgee or windex, and sailing largely by 'feel', bearing off a little as the wind picks up, and luffing a little when you feel the wind dying, so you maintain a good overall speed.
Needless to say, you adopt the same technique when sailing unarig, and remember to sit as far forward as possible to reduce drag.
In short - DON'T RUN IN A CAT.
Hope that helps.
Paul Smith (1961 Beaver S.C)

George C replied:

I have a different perspective on this. With a jib, in the vast majority of cases you need to gybe. A good rule of thumb is to keep the bridle wire tell-tale on or just in front of the bridle wire. It is very occasionally a benefit to run in light winds if there are waves in the direction of travel but this is unusual.

Una rig, it almost always pays to virtually run. By this I mean burgee pointing approximately at the windward rudder. Sailing last weekend with a jib gybing I was overtaken by una-rig boats sailing very close to running as a una-rig is so efficient sailed this way. In my experience you can get good speed with the burgee pointing directly behind you or even almost from the leeward rudder. Chris Black is a good example of this technique. Waves and wind speed have a big impact on the best angle. So keep experimenting and if you haven't got a burgee get one as there are just as many windshifts on the run and you loose less time gybing than tacking so it is even more tactical.

I wonder if Paul has a burgee and if so does he look at it as he points in almost the same direction as me downwind!

Best Regards

George

nick replied:

Many thanks I will get a burgee!! I will have to have a play ,I think 2up you lose a lot of acceleration. I have tried to learn from the hobies but they have stacks more power.I still have a lot to learn
best wishes

James replied:

"Quote" In short - DON'T RUN IN A CAT.
Hope that helps.
Paul Smith (1961 Beaver S.C)"Quote"

Never say never !
In a Dart 16, in very light wind, it usually pays to run.

Dartful Codger replied:

OK so I'm talking Dart 15/Sprint 15 configurations, but remember - running means sailing directly downwind with the sail square across the boat. If you try to do this in a Sprint 15, you will at best deform the sail, which will go 'S' shaped round the shroud wire, and at worst, consume battens at an alarming rate.
Clearly the English language is even more complex than sailing.

nick replied:

Tougher question than I thought.

George C replied:

Well, the common thought with cats and high performance dingys is that you are faster gybing than running. This is for several reasons, e.g. boats can get up on the plane this way which is faster, or the sails work more efficiently (this is true with jibs and asymetric spinakers) or, the shrouds are so far back it is not possible to get the boom out at 90? to the boat, (the correct position for traditional running). This last point is true for a Sprint 15, EXCEPT that there is no boom. If you let your mainsheet (standard length from Steve Sawford) all the way out except for 1 m (amount on the tramp) then most of the sail is at 90? which makes it efficient for running.

I have sailed this way for 10-12 years and have never broken a batton just by letting the sail bend around the shroud and I have sailed in some pretty heavy winds. Gybing can cause battons to break if uncontrolled, but not letting the sail out aginst the shroud, not in my experience anyway.

We could discuss this all day, but it is much more fun to buy a burgee, come along to some Sprint 15 events , experiment and have fun. You never know you may invent a different way of saling fast downwind that we can all learn from! There are definately all sorts of angles being sailed from broad reaching, to dead running (which I do quite a lot) to sailing by the lee, which also seems to work pretty well sometimes.

Happy experimenting!

Dave replied:

It must also depend on the length of the run.

The time it takes to do two gybes and accelerate again is more significant on a short run.

George C replied:

Don't worry, once you have mastered gybing you lose virtually no time at all.

Nick replied:

This is interesting stuff I have found saling deep especially two up again in light winds to be effective but was always mindful of ' dont run in a cat'.
Out of interest I find it hard to believe that the same handicap applies to two up sailing as it does to single handed(one sail) because when returns are made to the RYA is the mode specified if not how do they separate two up from one up certainly in the case of our club I suspect the return is just made as a Sprint 15 .Iwill find out.
Any one got any thoughts?

Dartful Codger replied:

Handicap numbers are always a talking point, particularly when cats sail amongst monohulls, since the performance curve is so different. Hence in winds below 15 mph, a cat will almost always lose out to a monohull, however good the helm, but conversely, given a constant wind strength of at least 15 mph or above, a cat will generally beat the monohull in a race of at least 1 hour.
Regarding the Sprint 15 PYs, the number is the same for 1 sail/1 person i.e. unarig as it is for 2 sails/2-up, since in 'average' conditions, the extra power from the jib is negated by the extra weight of the crew, therefore these two modes are not separated. However, given a windy day and a largish course, the 2-up boat would be favourite to win over unarig, but lose out to unarig mode in light conditions.
Swings and roundabouts I think is the phrase therefore, since you can't really alter handicap figures according to the weather.
Finally, regarding my earlier e-mail on running, I perhaps should clarify that a unarig cat will usually sail deeper than 2-up or Sport mode with jib to make best progress in a given wind strength and direction, whilst otherwise employing the same techniques.
Paul Smith (1961 Beaver S.C)

AndrewHannah replied:

Dear Nick,

I am not sure what point you are making. You seem to be inferring that the two-up two sail handicap, is unfair as against the single hander una-rig. You cite the two-up version has a slight advantage by sailing a lower course in light winds. Are you saying the two-up version should have a lower PY number?

An unique feature of the Sprint 15s, is that both formats race side-by-side on the same PY numbers. It might not work with other classes, but it works perfectly well with us.

Having said this, I am gratified to learn that there is at least one individual in the country that has some faith in those RYA questionaires. I recently had a long chat with a very respectable Sprint sailor who explained what happens to the questionaires once they are returned to the RYA. I have to admit that we both had a good laugh about it!

Nevertheless, I realise that we shouldn't laugh at the well-meaning RYA. I am sure the Sprint 15 association would be very interested with what your club submitted in its questionaire. eg, were there any calculations? We would be equally be interested in what the RYA replied, if anything.

Andrew, Sprint 15 class capt, TBYC.

nick replied:

Hi thanks for your input.I did not cite that 2up could sail deeper and had any advantage over una rig, but from information gained from this thread,I felt that it might be more efficient than the traditional 'prependicular to the wind indicator' route.
As I dont sail in a fleet of sprints py becomes more important in handicap raceing.
If you agree with Dartful, as I do, that 2up is slower in sub 15mph conditions. Most raceing in the UK is done in lighter winds force 3 and below.It follows that 2up then has an incorrect py.
(the national 12 fleet looked at wind stats. for their meetings and concluded it was better to design a light wind boat if you wanted to win the nationals.This is also why Hobie and the vortex classes are adding asymetrics.)
So if the RYA were preforming correctly, and separate figures were produced for 2up and una rig then I think you would see a larger handicap being given to 2up.
However you seem to have information which implies that they are not using the information correctly.This should be taken up by the class with the RYA as sailing on a non competitive handicap is detrimental to the class.
You say the system works prefectly well, but a quick scan of the traveler results shows that two up preform generally badly and I could only spot one top 10 result in 7 years.
My point is I would like a more reflective handicap for handicap racing at club level . I do accept this would then have an impact on 2up vs una rig. But to me it makes an interesting discussion.

AndrewHannah replied:

I'm still as mystified as ever, both as regards motives and rationale. Suffice to say, the association is entirely happy with the status quo. As mentioned in my post of 26/10, the handicap system works perfectly well with us, even if doesn't for other classes.

I didn't know the Vortex was adding a spinnaker. I wonder what the price of a new Vortex would be now? As regards the National 12s, we differ fundamentally insofar as the Sprint 15 is a one-design class.

As mentioned in my previous post, the best course for Nick's club to take, would be to submit their own calculations and conclusions to the RYA. Then we should all sit back and wait. And wait. And wait. And wait..........!

Andrew.