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Board » Technical Discussion » LP and the 2017 Iceland TR.

Posted by sol Posts 296 Registered at 2008-08-14 11:08:14	2017-03-02 13:47:22 - LP and the 2017 Iceland TR.
	In response to rumskib 2017 Iceland TR report. I’ll start with my congratulations for another rumskib win as also for the remaining podium place holders. Apart from choosing the best starting hour and boat trim, one of the clues to get a good result with this kind of go fast boats sailing on the Polar “red line” zone, is the maneuvers management. The reason was explained, again, by rumskib on his race report - attached here for posteriority - and, has to do with the SOL LP. I don’t get tired to repeat it is totally unreal to have a boat of this kind only recover 100% Polar Performance 30 minutes or more after a normal gybe at high speed (note: “normal” here means, like IRL, from downwind sailing to downwind, as an example: from TWA = -151,00º to TWA =151,00º). The actual trend in design for racing sail boats (mono or multihull) is the use of foils. With those appendices you get one big effect coming from a tremendous decreasing of the boat wetted surface and consequently, the minimizing of the hydrodynamic drag bringing not only a good burst in boat acceleration but also a higher speed above the water. In this respect and in the present, SOL was already losing the right direction, not to mention the near future. I’ve made some calcs - pls see second file attached - assuming some simplifications, for having an idea of an normal gybe vs. a “pirouette” one, being the last a way, or better, a trick (there are others) to elude the SOL LP penalty. When SOL races are increasingly decided by the second, there’s not much left to think/say about the right orientation SOL should implement, something that I’ve already pronounced in previous coms. Anyhow, I repeat here my suggestions as rumskib had misunderstood part of my words in his report. Stop the LP penalty (like you do for the ice boats races) and start applying penalty for the skippers who use/abuse on abundant boat maneuvers. My comments were/are clear. The lack of sportsmanship does not come from the tricks skippers use to elude the LP but, to something rumskib and other already know: extra maneuvers abuse. João/psail Attachments Normal_gybe_vs._a_pirouette_one_1.pdf (53.6 KB) Iceland17_REP_rumskib_1.pdf (69.9 KB)
Posted by JB Posts 305 Registered at 2013-03-07 08:54:34	2017-03-02 13:51:36 - Re: LP and the 2017 Iceland TR.
	The previous com was from me (psail) logged as "SOL". My apologies for that mistake. João/psail Sail Fair.
Posted by kroppyer Posts 346 Registered at 2010-02-05 15:25:55	2017-03-03 02:41:45 - Re: LP and the 2017 Iceland TR.
	"start applying penalty for the skippers who use/abuse on abundant boat maneuvers" I agree, BUT: (1) this needs to be automatic (no human interaction, no protesting other people on "tacking too much") (2) the penalty needs to be in the form of a slower boatspeed. That's the only option I see. Boat must [in my opinion] have free movement: you must be able to tack back within 10 seconds after you see you made a sign error for example. (3) a penalty for manoeuvres [whether it's abusive or not] may not allow for tricks: A single command to change course must always be faster than some series of commands. (4) the penalty must be predictable in a sense that users/sailors/solers can have an intuition of how large the penalty will be before they decide to make the manoeuvre or not (5) all frequent, significant course changes must be penalised: polar hopping (without changing tack) every x seconds corresponds to changing sails every x seconds, which is [I think] just as much of an abuse as changing tack every x seconds and should thus be penalised similarly. The system we currently use to penalise manoeuvres (what you call "LP") actually passes requirements (1), (2) and (5) except in very light winds. But it fails on: - requirement (3): because for example the two step gybe and three step gybe are sometimes faster than a simple "one step"-gybe - requirement (4): because for example the 93%-rule is not intuitive I'm interested to see - ideas for new "manoeuvre penalisation systems" that pass all 5 requirements, - arguments that one of the requirements is not essential, or - arguments that we need more requirements.
Posted by JB Posts 305 Registered at 2013-03-07 08:54:34	2017-03-03 11:03:47 - Re: LP and the 2017 Iceland TR.
	Viva Huib, Good morning and some further comments on this controversial subject. (1) Protesting. Well, it’s part of all skippers’ rights, namely. They are consigned in every Sail Rules I’ve memory. Is also a fact (of life) the possibility for our committed faults being judged by our peers, and not exclusively by SRC. More fair than this isn’t possible. Does SOL want the effective appliance of SRR to be the exception? I don’t think so. (2) Penalty. Huib, madly tacking/gybing along a rhumb line, especially taking profit of an inadequate boat LP formula, by miles just cannot be confused to a simple TWA signal error input/accident or, a bbq recover ops. It is intentional. It is unsportsmanship conduct so, obviously, should be penalized. And not necessarily in your prescribed (only) format: BS’s reducing. Unless the LP automation drives the BS to plain zero in a short time and for a long, long period it won’t fill the penalty intentions. Here I’ve a large doubt this can be auto implemented (hope my feeling is wrong…). Anyhow, an auto LP should be boat dependent, not BS one. Otherwise, and again, you just can’t cope with the extremes. As an example, foiling boats, especially when tacking under foil speed (note: mind you also the large jump in Polar before reaching foiling cruise speed), and the heavy’slow ones (where the “crime” pays - vide Tall Ships races episodes). While waiting for the desired “auto LP” penalty implementation and just using the basic principles entrusted in Clause 69, under a filled and valid protest (1) a simple option for this penalty is: “DSQ”. You just need two things: 1 - Extensively public information of the rule even if the rules unknowledge shouldn’t be fundament for escaping their effects; 2 - Keep for every racing boat (just during eventual protest procedures times) a detailed log’s record as de facto protest/s should be analyzed in post-race period. (3) and (4) are pacific and desirable, me thinks. (5) Is highly disputable in the light of the foiling boats trim for reaching/maintaining foiling speed (recommend all to look for a foiling boat Polar). Resuming. The actual LP penalty went on the excessive side bringing much worse effects than the ones we wanted to avoid. João/psail Sail Fair.
Posted by kroppyer Posts 346 Registered at 2010-02-05 15:25:55	2017-03-06 00:45:05 - Re: LP and the 2017 Iceland TR.
	Maybe our disagreement is in the original problem, not in how to solve it. I'm OK with boats tacking an unrealistic amount of times, as long as it slows them down. A winning strategy should never include a clearly unrealistic amount of significant course changes. If you want to make a saw-tooth-track, you're very welcome, but be prepared to loose ground quickly. That's how I think it should work. (Currently it doesn't work like this, should some uninformed reader wonder ) I have a feeling you don't agree with this, and that's why you want a more rigorous/extreme solution to the problem. It seems you don't want people to be able to do an unrealistic amount of course changes at all, but I don't understand what the problem is here. Please enlighten me, or correct me if I'm wrong in my assumptions
Posted by JB Posts 305 Registered at 2013-03-07 08:54:34	2017-03-07 18:20:08 - Re: LP and the 2017 Iceland TR.
	Good afternoon Huib and all. Probably we don’t disagree, at all. There is one original sin: the LP formulation. This issue results from an inadequate SOL LP function - it massively fails because it depends exclusively on initial BS immediately before any maneuver. Unrealistic amount of gybes/tacks is …. unreal, de facto and it should be penalized, which takes us to the penalties options. The actual penalty system (SOL LP) doesn’t work on the “extremes”. It has to be reformulated by some means and, from what I understood, it involves recoding the SOL “engine”. The million dollar question: when it will happen? While we wait for that answer my suggestion was practical and temporary (till the code issue is solved): apply simple and fair rules. Like IRL people are free to sail whatever they like. It’s their right but, there are the “olympic” minimums, or better, responsibilities, the ones coming from rules. João/psail Sail Fair.
Posted by kroppyer Posts 346 Registered at 2010-02-05 15:25:55	2017-03-08 04:38:00 - Re: LP and the 2017 Iceland TR.
	The calculations that determine performance loss and recovery can be changed quite easily. However, there are some restrictions the new formulas need to satisfy, otherwise it might become difficult to implement them. One of these restrictions is "no memory": recovery and loss are based purely on the last known state of the boat, e.g. we can't keep track of when the last course change was. I believe that it's possible to design a new set of performance formulas that do not allow for tricks, penalise frequent course changes, and still satisfy the easy-implementation-restrictions. As we seem to agree on the problem then, I believe that changing the performance calculations is the solution to the problem. I hope you agree (if not, I'm interested as to why this does not solve the problem in your opinion).

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