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Planing in 12s.

Started by Jimbo42, 29 Nov 2006, 06:42

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Jimbo42


Lukepiewalker

I suppose it depends why you are asking.
I have heard it suggested that a hull which planes early doesn't necessarily have the ultimate top speed.
And I've never noticed much of a 'hump' when I had my twelve... certainly no where near as noticeable as on a GP14 or similar... so ti could be we have already evolved dynamically humpless hulls.... ;D

Jimbo42


Lukepiewalker

Ah...
Could you make some kind of a 3d pie chart.... I like pies.... ;D

I suspect the problem will be a lack of quantitative data, qualitatively people will probably be able to give opinions on which boats plane earlier than others, but I fear raw numbers may be elusive....(whistle)

On the crew weight front I believe designers draw the lines with a crew weight in mind, so maybe the designers can chip in on that front. I suppose it comes down to what happens to the underwater shape when overloaded....(think)

Anyway, I'll shut up now and let someone who actually knows what they are talking about chip in
(stars)

John Meadowcroft

There is an argument for the Final Chapter as it is perceived to be a good weight carrier.  I infer this to mean that in marginal stuff it is not so bad for heavier people as other people as other designs.  Our experience sailing heavy is that it goes very nicely downwind when it is substantially not planing conditions, but loses out to a Feeling Foolish when it is more puffy.  Whether this is because the hull form is doing something special is another question.

The real secret of the Final Chapter is probably that you dont have to be fat to sail one!

Otherwise I think strong contenders will be Baggy Trousers and Feeling Foolish or is just the good sailors that had those or is it that the Baggy was regularly sailed very light.  

meds

Jimbo41

Thanks for your input lads.

Is there anyone out there putting any serious numerical effort into this type of thing? You perhaps Davidg? I know you have a thing about N12 foils.... ;)

Cheers,

Jim.
 

Mikey C

Data logging is most definitely illegal in a 12...
Carbon Toys for fast girls and boys!

//www.aardvarkracing.co.uk

johnk

Illegal only while racing surely?

JimC (Guest)

Realistically the only thing you could really do would be an extended program of tow tests like the Bethwaites do. Its a lot of hassle which is probably why they're the only folk who've done it. But it probably explains an awful lot about why their boats average better than the average SMOD. It would be most interesting to tow a selection of Cherubs and Nationals and get some data...

Jimbo41

I think that's a pretty good idea JimC.

What do others think? We could have a go on a lake this Summer. Say one Feeling foolish, one Final Chapter, Numinous, Enigma, Baggy, Man O' War and with a whole host of different crew weights???? For some perhaps as interesting as dragging a teabag around on a long piece of string - not everyone's cup of tea  ;) For others perhaps a revelation.

The only thing is it would only deal with hull profiles and not rig-hull combinations as well as position of the wind..... :-/

Jim N3130 and N3470
 

Alex D

My favourite approach is a long knotted rope and an hour glass. I have problems counting the knots while  holding the main sheet at the same time.... but at least the hour glass floats. 8)
Alex <br />(ex N3455, N3246)

Mikey C

I think varying the weights will only muddify matters somewhat. Best baseline would be to test all the boats with one crew weight. You can then test (with rib/gps/scales) how much resistance at certain speeds and try and plot the results but you would have to do it from a gantry to the side to keep the rib wake seperate.

Rig is irrelevant to the question, as is really the angle of wind.

Whats an Enigma? Not heard of that one.

My top planing list would read something like this:
Big Issue
Baggy2
Foolish
Baggy
Chapter

I think in marginal conditions some boats get to plane earlier, but others go faster before they start planing which can lead to swings adn roundabouts. If you can get your boat on the plane its all good.
Carbon Toys for fast girls and boys!

//www.aardvarkracing.co.uk

Jimbo42


JimC (Guest)

If you guys can organise things and its reasonably handy for me in the South Easy then I could drag along my 70s Farr Cherub as an alternate, should it be welcome.  Be interesting to see how a more planing shape would compare. I'd expect the Nationals to be much more slippery at most speeds though. And Mikey C could take a look at my Bethwaite wing mast [grin]. With discipline and a GPS one could probably get through tests far faster than was possible the way Bethwaite used to do it with a measured distance and a stopwatch.

Jimbo41

An alternative date for me would be the middle of Easter - I'll be picking up N3470 at that time....

Anyone interested appart from JimC and one other of whom I know?

Incidentally, the other chap's a member of the NTOA and is doing a degree in Marine and composites at Plymouth uni. We might be able to get a little support etc....

Cheers!

Jim N3130 and N3470 (riding along on the crest of a wave.... 8))
 

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