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Definition of Planing

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JimC View Drop Down
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 27 Mar 19 at 4:13am
Originally posted by Peaky

   Why not just allow one pump per gust (ignoring that definition difficulty for now) .

Because given the gust definition difficulty it would basically be allowing continual kinetics. Just consider the average light airs run...
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Post Options Post Options   Quote 423zero Quote  Post ReplyReply Direct Link To This Post Posted: 27 Mar 19 at 12:59pm
Going back to the Enterprise, would it be better described as skimming?
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Post Options Post Options   Quote jeffers Quote  Post ReplyReply Direct Link To This Post Posted: 28 Mar 19 at 2:09pm
Originally posted by 423zero

Going back to the Enterprise, would it be better described as skimming?

More likely pushing the level of the lake down.....
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 28 Mar 19 at 7:24pm
Originally posted by jeffers


Originally posted by 423zero

Going back to the Enterprise, would it be better described as skimming?

More likely pushing the level of the lake down.....


That's the Comet Trio, isn't it? You can plant spuds behind it in a blow. Feels fast, though!
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Post Options Post Options   Quote mozzy Quote  Post ReplyReply Direct Link To This Post Posted: 30 Apr 19 at 10:32am
Originally posted by Peaky

I donít know. I donít think these 200s are, but others may disagree.

200s planing?
Looks like he's just about to get planing at 1:26, if the crew would just move out... but generally no, not planing 

I'd say the Ent was.  

Here at 0.33 you can see me not planing after a gybe, and then a big pump to initiate it... Plenty of 200 planing in that video (but it is 20 knots). 

Dan's calculation a few pages back is probably pretty accurate for the speeds required to achieve planing... but, my feeling is you drop off the plane at a speed below that which it takes to get over the bow wave (maybe Dan could comment if that is correct). And although 12 knots sounds a lot you can get instantaneous speeds easily over 12 knots in a 200 even in less than 15 knots of breeze, but lasting for less than a fraction of a second. 

When you shift your weight back violently and give the sail a pump it pushes the boat over it's bow wave. The boats average speed may be well less than 10 knots, but in that moment it's quite easy to get well above. Once out you can keep moving back and the boat will support itself planning on the wider flatter aft section at speed below hull speed. 

For example, assuming you get up on to the plane at 12 knots, but drop off it at 9. If you can ooch or pump to get over the bow wave by achieving 12 knots for a instant when otherwise you were doing 8 knots, you can then, with the same energy sustain steady planning at 10 knots due to less hull drag.

Generally I find a pump when you get hooked up on the back of wave really does help, but timing is crucial. It gives you an instantaneous boost which gets you over the lip. But, every action has an opposite reaction. Pumping is very energy inefficient, you might push the boat forward 2 foot in a pump, but then it slips back 20 inches when you ease the sail and restore your body wait to original trim. Slipping back 20 inches isn't an issue when the pump got you on to the plane at sustained 2 knots faster speed, or gets you on to wave which carries you 50 meters... but if you're not timing these pumps to take advantage of additional gains, then not having your sails or weight correctly trimmed during the pump can be more disruptive lose you those 4 inches which you invested a heap of energy in by pumping. 

In the very light winds, when you're hardly moving, then pumping, even if you're only clawing yourself forward a few inches at a time is a lot faster than sitting stationary, and you have very little true wind to worry about neglecting anyway... but few regatta's are raced in this, although I accept it makes up a lot of peoples club racing and is where, I think most of the concern with allowing free pumping is.

Above is really discussing 'macro' level pumping. With a large body movement and full arm length of sheet. It takes about 1- second for the pump and 5 seconds to slowly move back to the pre-pump position. You then get the fanning style of pumping you see on the 470s and windsurfs upwind which don't give a large instantaneous jump in speed, but input an extra boost of energy continually in to the sails. I think this is very hard to achieve in a dinghy though as you need a full persons body-weight in direct link to the rig... you don't see the finns doing it as most their body-weight is supported by a heavy hull. 






Edited by mozzy - 30 Apr 19 at 11:28am
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Post Options Post Options   Quote Fatboi Quote  Post ReplyReply Direct Link To This Post Posted: 30 Apr 19 at 12:37pm
Originally posted by mozzy

  you don't see the finns doing it as most their body-weight is supported by a heavy hull. 





The Finns are not allowed to pump upwind - written into class rules. 
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Post Options Post Options   Quote mozzy Quote  Post ReplyReply Direct Link To This Post Posted: 30 Apr 19 at 1:22pm
Fair enough, bad example then! 

But still, i recon it would be hard to achieve what the 470s do in most hiking classes. And it's fairly obvious if someone does it at club level.... so much so I don't think it's much of a worry for club racing. 
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