Handicap - A Final Solution?

Originally posted by Daniel Holman Originally posted by timeonthewater IMS..when I was yacht racing was called the International mystery system. Problem was, it was impossible to fathom for the mere mortal.. Far too many parameters, affected your handicap.   Without the Deckman computer on board, we simply had no idea of how well were were racing, because our new racing mindset was now programmed to racing against the VPP's, and straight-line speed. Boat on boat action was avoided to a certain extent, unless we had the full after guard team, the tactician and navigator working full time to call whether it was worth tacking for speed, tactical or fleet advantage. 500K later....the one design J24 fleet racing was far more enjoyable You wouldn't wish VPP and polars on any club racer/race officer to make an IMS style handicap system work Graham..go sailing.  None of this matters    You could make a "one number" yardstick from a VPP, and use it in precisely the same manner as PY, but what I was driving at was that it would be every bit as imperfect as PY in trying to give a single number for all boats on all courses on all waters in all windstrengths.A stopped clock tells the correct time twice a day and all that.

Very true, but if there was some theoretical supplement to the PY then it might be useful for classes with fewer actual returns. Also, it is not beyond imagination that, say, Merlin Rockets will lower their hull weight rule. Rather than enjoying years of banditry whilst the returns come in, it would be possible to get a reasonable estimate of the delta.

Originally posted by Daniel Holman Wrote this in the other thread oops! Physical testing of dinghies "in the field" would be impossible to do in a scientific and meaningful manner whereby you could quantify every aspect of the aero and hydro characteristics accurately enough. Big boat IMS (and I believe subsequently IRC) handicapping sought to handicap the boats based on their VPPs - i.e velocity prediction programmes - maths models of the aerodynamic and hydrodynamic components of the yacht which can resolve the equilibriums for any speed / heading / sail set to effectively produce polar charts from which theoretical times around theoretical (perfect triangle or ww/lw or point to point) courses. Most polars that you get on leadmines to steer and trim to are derived from the VPPs that have been created rather than physical testing (far, far more expensive given that you'd have to do extensive wind tunnel and towtank / CFD analyses to populate all the physical models). There is no reason why you couldn't run every dinghy class through a vpp, apart from effort and expense. Trouble is then, what windspeed would you decide to take the relative handicaps at? Thats a can of worms to start with. Also, the VPP number will have to be given for whatever course config (i.e. ww/lw; specific point to point etc) that has been fed into the computer. I don't need to overstate the disparity in performance between most classes depending on time spent on which leg of the course or wind strength.

Not only but also......

Some rich guys in the USA sponsored the research that resulted in the MHS (later IMS, later ORCi and ORR) VPP in the 1970s and the current developers of the ORR and HPR rules are still sponsored by wealthy East-coast USA owners. All these years later, VPPs still aren't very effective for boats that plane or (worse) on/off plane as the latter is a significantly harder problem to model. Nor are they very good at predicting the relative performance of boats with significantly different typeforms which is why HPR(and IRM before it) is highly type-forming by intention. Dinghies are wildly more variable in typeform than modern racing yachts. Nobody has paid for development of an effective VPP for dinghies and I doubt anybody is about to do so.

The idea that some simple spreadsheet is going to produce numbers more reliable than PY is a fantasy.

P.S. AFAIK IRC is not VPP-based (in the sense of generating polars). You certainly can't apply to the IRC rating office for polars corresponding to your IRC certificate (whereas for ORCi you can).


Edited by blueboy - 08 Sep 13 at 9:43am

Originally posted by iGRF Originally posted by yellowwelly Originally posted by iGRF Is the only way to avoid the chaos that continues to annoy and aggravate at every turn. Try class racing... really it's so much nicer to know it's you, not the boat or the arbitrary number that need some work. Been there, done that, got the T shirt, and now without a huge amount of training it just means if it's light I win if its windy you win, just a body weight procession. Which is why I find the whole racing not only against the man but his spreadsheet and the system so compelling, and it's Friday, shall we do tidal lee bow again?

I suppose that some of this matters if you cannot see where you are going or spot the next mark. Not a problem with point and shoot pond racing.

 great post