Dart 15 Forums

Bob (for Mark Sanders) wrote:

Mark Sanders sent this in to Nick & I. I'm just putting it on the chat site to open up the debate.



Hi Boys,

There follows some thoughts with respect to sailing the "15" 2 up.
It's a well known fact that the "15" sails best in una rig, one up. With a crew onboard the handkerchief jib just does not seem to compensate with the additional weight. Personally speaking and to prove a point, I achieved 13th place at the Herne Bay Nationals sailing one up, this year at the Whitstable Nationals I came joint 30th (alongside Hilary) sailing two up. I could of course be sailing worse these days, age, weight, short term memory now all going against me but I think not.
Having said that, sailing two up is good fun, there's someone to talk to for instance (you don't have to be a "Billy no-mates" to sail a 15) and the "team spirit" kicks in too. I can't help but think we are missing an opportunity here, there must be loads of parents in the same position as I who want a performance boat, one & two up.
So what am I getting at?
(Draft Proposal): Why not allow the fitting of a gennaker for the 2 up boats and if it was to take off, have separate race starts for them at TT events and at the Nationals.
Now I know, suggesting this type of thing in a strictly one design class will result in requests for many of my bodily parts to be removed, but I think it could be a big step forward for the Class.
Look at the Tornado for instance, it has revitalised what was an ailing class in the face of stiff competition from the new "sport" classes.
I've made initial enquires with respect to the carbon fibre combined chute/pole made by Full Force Boats for the Tornado, if it turns out to be silly money well at least I tried, but I think keeping the 3rd sail off the tramp is desirable, less cluttered etc.

Your thoughts on the above would be much appreciated.

Kindest regards

Mark "Mad Dog" Sanders

Simon Liston replied:

I'm with 'Mad Dog' on that one - well certainly as far as getting more power available when sailing two up.

Most of my Dart sailing has been of the social 'cruising' type or taking the other half and kids out so it's not normally too much of a problem *however* when sailing with mates of equal or, and it's hard to believe, greater weight than myself the Jib doesn't really seem to contribute much. (In fact one friends has commented that his wife has under garments that would eclipse the jib - I've seen her and it's true! )

That said, and showing my ignorance of such things, I have no idea what you're actually talking about and what it would comprise - is it a simple pull-up/pull-down kind of thing?

As for the silly money I guess it's bound to be as everything seems so expensive - The pole will be at least ?300 [carbon fibre anything doesn't come cheap] plus fittings at at least another ?100 and of course the sail at ?400. I guess 'silly money' is a relative term - being wednesday and a double rollover my viewpoint may hopefully have changed by about 8pm tonight

p.s. It will of course cheese a number of my dinghy owning friends off further as they think the Dart is more than fast enough already!

Mark Aldridge replied:

I'm all for more power, but I think you're forgetting something!

The maximum velocity of a Dart 15 as with other cats is on the Reach, be it broad or fine what happens is that with too much power the bows bury and over you go - Pitchpole.

I'm a heavier sailor who enjoys the faster conditions, but with too much sail at the front, you're in trouble.

Take a look at the Inters, Shadow, Spitfire etc as they all have greater bouyancy designed into the bows to compensate for the extra pressure exerted when more sail area is powered up...

In lighter winds however.......

Mark Aldridge
Dart 15 #1966

Gordon Goldstone replied:

Gennaker on a 15?
If you come down to Queen Mary you might see one.
Some of you know I've been messing around with a gennaker project at Queen Mary this summer.

I still wanted to sail single-handed, so for ease of use I decided to have a go with a furling asymmetric sail fitted on to a straight, nothing fancy, aluminium pole. I had the sail made for me, it's not big, probably around 8 sq m. It's not perfect by any means, but it goes well, and is very easy to use even single-handed as it just unfurls or furls up in seconds. It looks like the jib furled up but longer. I've dispensed with the jib and I've now got less rope round my feet.

I can tell you that the angled sail lifts the bow on a reach but watch out for strong sudden gusts, as at that moment, the rapid acceleration and hull lifting send the bow down and call for immediate bearing-away action! You learn quickly! Once the boats up and going it lifts the bow and drives forward. Personally, I think it's a lot of fun and I prefer it to sprinting.

As for costs, I've spent ?200 on the sail, ?50 on the pole and probably ?100-125 on the other bits. I've gained a lot of knowledge since I started this but I'm still not sure if this is a good solution or not. I?ve learnt that there are several plusses and minuses.

I'm tempted to have a go with a MK 2 version now I've learnt a bit and I've love to see a version with one of those new chutes that I saw on all the formula 18?s at Grafham. Whether it works well or not depends hugely on where in relation to the wind you want to sail. It?s no coincidence that all these boats with big asymmetrics only want to sail up and down wind, that?s all they can do unless the wind is light. For 2 ups and cruising I reckon a moderate size gennaker would be great fun, for single-handed it?s a bit more exciting.

Gordon.

An Interested Enquirer replied:

So just how much benefit does your interesting experiment provide - do you leave any fellow fifteeners at Queen Mary in your wake? Or is it a case of too early yet for you to have worked out which angles and trim goes best in different conditions to be able to get the most from the rig?

I'd guess that the latter could be quite an issue to sort out without extensive trials alongside a Sprint boat for comparison.

I'd also like to point out that I think there's a significant difference between optimum sailing technique on a standard 2up or Sprint Dart 15 and a 1up Unarig. Is some of Mark Sander's lack of performance 2up at Whitstable compared to 1up at Herne Bay down to this factor rather than the known disadvantage of 2up in less windy conditions? Did Mark do better on the windier days when the advantage should have been in his favour?

But I do agree that 2up is no good in lighht conditions.

Gordon replied:

Dear interested observer
I wish I were leaving everyone behind in my wake, I wish, I wish. Unfortunately it doesn?t seem that simple. I?m sure that it?s quicker, but not always. What I have learnt is
1. That getting the balance between sail area, wind strength and sailing angle to the wind are key.
2. If the wind and the sailing angle combine to give a situation where you need more sail area, then this will work.
3. But, if the wind?s very light, it can still be quicker to sail straight downwind rather than sail the angles.
Obviously depends on how big your gennaker is, but that?s the whole thing about getting the balance right. If you only want to sail up and downwind, it?s not such a difficult compromise, but if you want to include a square reach you need to downsize your sail a bit.
Regarding my personal experiment, after a bit of practice I?m fairly sure that my new sail (7.5-8sq m) is still too small to give a really appreciable downwind gain. Also, I?d like it to be able to get out on the wire on a reach. I haven?t yet figured out a ?safe? technique because things start to happen very quickly as the sail starts working. I suspect more courage is required.

George Stephen replied:

Gordon,

I must try to get my act together and arrange with you a date so you can try out your genniker rig directly against my Sprint in a series of specific comparative reaches and runs, ie other than in a race. Surely this will help progress.

I've been reluctant to Sprint because of my shoulder problem, but as it's stood up fairly well to today's sailing (well done on beating me twice with both of us in standard unarig cats!) I think I should try Sprinting again to see if I can avoid the severe problems which have previously occurred.

George

Rick replied:

Just about to start my third year racing the Dart and would like to ask some advice
Regularly race against RS400?s and ISO?s so cannot win but try to reduce margin Over the line as an indicator to how I am progressing.
However there appear to be different ideas on the best way to sail down wind on the 15 with uno rig.
I have tried to sail the angles same as the isometric boats and also run straight down to the mark and have to say the direct approach does seem to be best to me, but is this correct or should I persist in reaching back and forth.
I have another cat to race against this year but as it is a Hobie 14 complete with twin trapeze and isometric I don?t expect to see it much apart from at the start.
Any guidance would be appreciated.
Rick

Dartful Codger replied:

Hi Rick,
Sounds like you've been there and done that, and rightly reached the conclusion that it is better to sail the more direct route to a down-wind mark.
Dart 15s do not perform well on a dead run, and it is a precarious angle to sail on anyway, since a slight wind shift could cause an unintentional gybe, possibly with dire consequences if sailing in a force 5+ at the time !
However, if you only sail a broad reach angle, or follow the ISOs, then although your speed will increase dramatically (from a dead-run angle), the apparent wind generated is not enough on a 15 to compensate for the much greater distance that you will sail to get from A to B.
It is therefore a question of compromise and feel that will determine the optimum angle to sail, but it will be somewhere between a broad reach and a dead run, but never one or the other - if you follow ! The fine tuning is down to detecting subtle wind shifts, so you always sail on the correct tack, but don't forget - practice makes perfect !
Best of luck
Paul Smith (Beaver S.C) South Yorkshire.

Rick replied:

Hi Paul

Thanks your advice, good to know that I am doing the right thing.
Start practicing again this weekend, hope to attend some of
the traveler events this year to see close up how you professionals do it.
(if I can convince the wife that we need a road trailer rather that the hall redecorated)
Thanks again your advice.

Rick

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