The Case for a VPP style handicap system.

Originally posted by Presuming Ed Originally posted by JimC   The curse of all these rules has always been that it seems easier to design a boat that is slow, but not quite as slow as the rule thinks it is, than it is to design a boat that is quicker than the rule thinks it is. Saying the same thing, IMHO. Main difficulty, AISI, is that the understanding of the basic sweet spot in terms of speed producing factors - length, beam, displacement, sail area is found relatively quickly. If you make a boat that's all around faster than the rule thinks it is, you've just got one iteration further down that road. But in a modern world where the designers' VPPs are much more sophisticated than the rule writers', that's actually a road that gets travelled pretty quickly. (The other option is a one-trick pony.)

Originally posted by Daniel Holman One thing that the PY can capture to one extent- at least for an average venue in a certain wind strength average sailors etc etc - in a stopped clock tells the correct time once a day kinda way.A VPP based system could never capture this sort of effect without serious fudging.BTW, pretty sure the wolfson unit has a dinghy VPP - why not have a chat with them about implementation and codifying every racing class in the UK Graeme?

Not such a bad idea, I'd like to know more about what factors their system employs, from what I've managed to garner so far, the traditional VPP's allow for heel and far more wetted surface than dinghies, so we need our own formula, like whatever it was that produced those V twin predictions. My thinking for that was rather than expect everyone to measure to that great a degree a certain bottom 'type' could be selected from a list.
like say Shallow parabolic rocker, type 1, type 2 etc. to add to the sail size, number, length, beam righting moment stuff.

Then once you have a solid base formula that the given boat has, it could at least be referred to by The PY muckers before they start applying all their stats.

So a given boat would have a 'scratch' number, it wouldn't stop the current system of clubs varying it according to their conditions, or ambitious organisers attempting to swell their numbers, but it would at least have a number calculated as a base point and the number would have a direct boat to boat relationship which is what is missing at the moment as some boats get left on the sidelines as the chatterati have their way with fashion fads of the moment depending on who is campaigning which class.

So to anecdotally explain what I mean, take the Blaze and the Phantom which were quite close, they both had different points of good performance, they were 1046 and 1047, both have been modified, both have been built in modern methods, but because the one performed better inland than the other they now have a mucked about differential, that couldn't happen under a maths based system and if it did, it could be ignored at clubs such as ours where there remains little difference the one with the other.

Edited by iGRF - 24 Dec 13 at 1:56pm

I have a dinghy VPP... Its not particularly good yet.

There is a lot of misconception surrounding VPPs, but a lot of the concerns expressed on this thread are valid. They can be fantastic tool if you can manage their shortcomings but expecting them to do too much is where they usually fall down.

Use of VPPs when designing keelboats has yet to result in the perfect boat. Probably because there's no such thing as the perfect boat.