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2 per 1 trap Asy's - where to next?
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oldarn View Drop Down
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Posts: 440 		Post Options Post Options   Quote oldarn Quote  Post ReplyReply Direct Link To This Post Topic: 2 per 1 trap Asy's - where to next?
    Posted: 14 Oct 09 at 12:30pm
Originally posted by Skiffybob

I think you'll find that Jim is actually talking about
back in about 1989/1990 when the first Cherubs put sprits on. The kite
sail area was the same as a symmetric kite, and the conventional kite pole
was 9ft long (so almost as long as the bowsprits).


[

So I would suggest that Jim (an certain other old gits on this forum)
actually know more about these subjects than you think, having been
here and tried it on development classes many years before the SMOD
market "invented it".



Surely it's not unreasonable to refer a boat with a 9ft pole not to be
normal!

As an old git myself I do appreciate reading and learning fro the likes of
Jim.

Regarding classes that have abandoned goosewinging, clearly it saves the
SMOD manufacturers cost, while in some cases considerably detracting
from the downwind performance.

A couple of years ago I discussed with a SMOD manufacturer the benefit
of having swinging poles on some of their slower and small kited
dinghies. The answer was simple. If it costs more than £25 then forget it.
So now this SMOD bonanza is over, there are left hundreds of
disillusioned boat owners who end up at the back the fleet and more than
likely requiring a tow home and only because of the meanness of the
manufacturers. Surely many of those boats were not fit for purpose, not
even having a goosewinging system.
.




thefastexcitingrunningasymmetric
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Skiffybob View Drop Down
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Posts: 842 		Post Options Post Options   Quote Skiffybob Quote  Post ReplyReply Direct Link To This Post Posted: 14 Oct 09 at 9:49am

It's not about PYs though, it's about the shape and weight of a hull and how it sails.

Coming back to the point about the Cherubs, back in 1991, they only had 13 sq.m kites, and yet the fixed bowsprit boats still won. This is because Cherubs were (and still are) designed to plane and not to dispacement sail, so the difference in speed is HUGE (more binary than any other boat I've ever sailed).

So if you take the Alto for instance, you have a long moderate hull which dispacement sails quite fast, and it's planing speed is not a huge leap up from that (same with a 400), so it will always pay to go deep.

That's why a fixed bowsprit on something like a 505 is a complete waste of time, and will be slower in pretty-much any conditions (and will get completely slaughtered in lighter stuff).

Which kinda brings us back to the thread, where for me a good 2PST club boat will be fundementally a dispacement hull with either a symmetric kite or have a swinging pole (so 420,505,Alto,Fireball,Laser 2, etc.), which perhaps explains why these classes are remaining strong at club level with good fleets.
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 14 Oct 09 at 9:40am
Thanks.  I guess the swinging pole reduces the PY by about 5 points?
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oldarn View Drop Down
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Posts: 440 		Post Options Post Options   Quote oldarn Quote  Post ReplyReply Direct Link To This Post Posted: 14 Oct 09 at 9:19am
Originally posted by Peaky

Oldarn,


Any feel for how much less time it takes to do a leeward leg with the
pole fully swung in a force 2-3? Or conversely, how much smaller your
kite is than it would have been if it was on a fixed pole? I'm just
interested in how much of a performance gain there is.



That is a mammoth question. At Deben YC upto 3 AltOs race, and usually
2. We have several times done the comparison. On a one mile running leg
back up the river we have several times done the comparison. In any wind
other than almost no wind (when it is necessary to do shallow zig-zags)
the running boat wins hands down. Our kite size is 17m2.

My judgment is that swinging a pole is of significant advantage on boats
with PY's down to 900. i.e.L4000 and 505 speeds. 505's swing their pole
on club courses and sometimes on W/L courses. Of course PY's relate to
kite size and perhaps a kite size above which there is seldom any benefit
might be around 22m2.
thefastexcitingrunningasymmetric
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Skiffybob View Drop Down
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Posts: 842 		Post Options Post Options   Quote Skiffybob Quote  Post ReplyReply Direct Link To This Post Posted: 14 Oct 09 at 8:37am

I think you'll find that Jim is actually talking about back in about 1989/1990 when the first Cherubs put sprits on. The kite sail area was the same as a symmetric kite, and the conventional kite pole was 9ft long (so almost as long as the bowsprits).

There was a train of thought back then that the symmetric solution would be faster round the course because of being able to go deep on the run (which turned-out not to be the case), and there was another thought that a swivelling bowsprit would also help on the runs (Dave Roe's original boawsprit on Norwegian Blue was a wing-wang). This also proved not to be the case because of the hassle, the extra weight and complexity, and the VMG.

So I would suggest that Jim (an certain other old gits on this forum) actually know more about these subjects than you think, having been here and tried it on development classes many years before the SMOD market "invented it".
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Ross View Drop Down
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Posts: 1163 		Post Options Post Options   Quote Ross Quote  Post ReplyReply Direct Link To This Post Posted: 13 Oct 09 at 11:42pm
Cherubs are normal dinghys, just a far superior normal.

Jim is talking about the more 'conventional' '97 rules
Cherubs.
Ross
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 13 Oct 09 at 10:54pm

Oldarn,

Any feel for how much less time it takes to do a leeward leg with the pole fully swung in a force 2-3? Or conversely, how much smaller your kite is than it would have been if it was on a fixed pole? I'm just interested in how much of a performance gain there is.
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Posts: 440 		Post Options Post Options   Quote oldarn Quote  Post ReplyReply Direct Link To This Post Posted: 13 Oct 09 at 9:50pm
Originally posted by JimC

Originally posted by oldarn

I'm not in a position to critcise the
swinging poles in the 400 or 4000, but I
respect the design ability of Phil Morrison and suggest that it is not the
system that is stupid!


Three points.
1) I have the luxury of tens, maybe hundreds more RS400 races than
Morrison did when he designed the thing. Hindsight is a very powerful
evaluation tool.

2) The job of the designer of a one design boat is to design boats that
will sell. There is no doubt in my mind that the swinging pole helped shift
a lot of boats when asymettrics were new. It made (and obviously still
makes) a difference in people's heads - the most important place.

3) Look at the angle between the tip of the pole and the mast next time
you sail an RS400 or 4 Tonner. Thats the crucial measure for sail set and
its suprisingly small. Then next time you are on a pole kite boat see how
much difference that small a change in the angle the pole is pulled back
makes to your vmg...

Like the boat or hate it, the device on the Alto is significantly different,
although to my mind if you're going to have a pole kite have a proper one
and get the rag right out from behind the mainsail...

The advantages of being able to quickly and easily gybe into gusts
downwind in the light are often underestimated. If you always gybe
towards the gust then the gust fan takes you lower as well as faster. The
extra hassle of gybing a pole kite makes a lot of difference. I learned that
the hard way the first year of sprit kites in Cherubs, when, expecting to
easily win the first light airs open with the only modern boat with a pole
kite, the sprits exploited the gusts better and I was stuffed!


I'm sorry Jim but you do talk a load of twaddle.

Re. 1, Are you saying you never swung the pole. Please answer yes ot no.
I don't go in for critising other boats but you deserve a medal for sailing
in such an uncomfortable boat so often and in particular when on your
knees praying that it would go deeper. I suggest you will find foresight
more useful than hindsight!

Re.2 So was the swinging pole just a con to sell more boats? I appreciate
you are speaking only for yourself (I hope)) when stating the benefit of a
swinging pole is only in peoples heads. I, and I'm sure others, find them a
benefit on the water.    I suppose it's the difference between seat of the
pants sailing and text book sailing.

Re.3 I don't mind how much difference pole swing makes to vmg, I prefer
to get to where I'm going in a shorter time and not at a faster speed.

The AltO kite can come out almost as far as a symmetric, but are you
aware they are a different shape, and don't forget the vmg ?

As regards your last para. I don't particularly wish to know the oddities
about sailing a Cherub since they are hardly a normal boat.

This interesting diversion from the topic and into goosewinging and
swinging poles has led to Jim's view that designs are only to sell boats.
This is born out by the multitude of mainly useless and unwanted
asymmetric classes littering UK clubs and pushed onto the UK by greedy
SMOD manufacturers. And it is this mess that has helped to destroy TPST
asymmetric club class racing.

thefastexcitingrunningasymmetric
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Posts: 8956 		Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 13 Oct 09 at 6:14pm

Originally posted by alstorer

Originally posted by Lukepiewalker

Most assymetric classes have banned such scandalous behaviour...

Really? Other than the notorious case of the 200, care to name any that have specifically banned it?

Fevas have, I believe.

The reason I've heard for banning it was that when coming into a leeward mark with some boats goosewinging and some playing the angles, things got somewhat dangerous. The more cynical reason I've heard was that goosewinging was so much faster in practically all conditions it had to be banned to force people to reach.

As for goosewinging a Firefly in a force 6 with a following sea, I've not been quite so sh1t scared in a while. Gybeing downwind in a bowsprit boat is rather easier.
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alstorer View Drop Down
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Posts: 2899 		Post Options Post Options   Quote alstorer Quote  Post ReplyReply Direct Link To This Post Posted: 13 Oct 09 at 5:54pm
Originally posted by Lukepiewalker

Most assymetric classes have banned such scandalous behaviour...

Really? Other than the notorious case of the 200, care to name any that have specifically banned it?
-_
Al
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