Oceanhippie.net - Tom's Blog

As a reluctant participant in the Darwin Sailing Club Handicapping system. 

OTB Beach boats usually come straight from the Australian Yardstick Lists  

Yachts its “Ask Fred”. Fred is our PRIMARY handicapper he is retired from racing, unlike me I have a conflict of interest its a called "Shaw Thing" and it goes. Fred is heavily involved in the club has been for decades, I also know he’s got a database of results and homemade software going back at least 50 years. A better choice I cannot think off! 

I consider my role as “collator of handicaps” I do my utmost to not set any, if I do I use maths wherever possible.  Example I asked Fred and he didn’t have numbers for “Joust” but Dinah Beach did. 

I took the handicaps for a boats in Joust’s division with BOTH handicaps at DSC and DBCYA took their DSC handicap and divided it by the DBCYA handicap to get a ratio and multiplied it something like: 

((Shaw Thing DSC / Shaw Thing DBCYA) + 
(Silverjack DSC / Silverjack DBCYA) + 
(Even Karma DSC / Even Karma DBCYA) + 
(Terminal DSC / Terminal DBCYA) + ) / 4 * Joust DBCYA = Joust DSC 

No handicaps are ‘Right’ they don’t work like that. I hope to make the fair. 

Why not just use the same number at both clubs? 

 Because ultimately handicaps are correction factors applied to a finish time. NOT a ratio of speed differences between boats either they’re less that 1 and the time goes down or they’re greater than 1 and the time goes up. But where the 1.00000 is is different between clubs. Sailsys and other ‘global’ databases are helping this but they drift on pivot boats and other factors. 

Pivot boats. 

For the sake of math, software, or the handicappers sanity when adjusting handicaps its usual to leave one handicap the same and push the others around to match it. If its chosen by a ‘good handicapper’ than this pivot boat will be both regular racer and reliable, we hope the software does the same thing*. This is how the different series or clubs deviate. Different pivots push different ways. When you have small fleets and inconstant attending that’s REALLY hard. I always try and compare to Zanzibar if I can reliable and consistent boat good all rounder (as opposed to my one trick downwind pony) I call this the Zandicap(tm)

If a handicap for a boat doesn’t change this is probably the ‘pivot boat’ 

Is it a performance based handicap?  

Yes and no – the software algorithms are, certainly. But an initial handicap has to be entered into the system. This is probably based on what Fred or failing that the internet thinks your boat should be able to do. We have such small fleets that there are very small datasets for the algorithm to get its teeth into. And DSC has a done some really dumb things to destroy the algorithms over the years. 

How to wreck the algorithm: 

The Cockup of the Sea - We used to take the duration for the Saturday Race + Duration of the Sunday race for cock of the sea and add them together. Or if you only did one day add 12 hours. No one told the Algorithm – it just saw one boat with a 4 hour time and another with a 14 hour time and changed handicap to compensate. Doh! 

The No Point Regatta – We used to count the SUM of the Results for the East Point Regatta as one set of Points in the Classic Series. And *Ahem* rigged a race too look right. Usually that would be setting fake finish Times 1 minute finish time for boat 1, 2 for boat two, 3 for boat 4 etc. The algorithm doesn’t know they are fake it thought they were real times! 

So the moral of this story is if you want to ‘sandbag’ the best way is to have someone fix the results in a dumb way. 

Hang on Tom just entered FAKE times into SailSys for the Patrons Trophy, has he just done the same thing…… No, he didn’t because he entered ‘proportional’ times. The average lap times I entered were fake, but fake in proportion to the boats actual performance so the algorithm is not broken – also there only one race in the series and I told sailsys to ‘hold the handicaps’. 

Hang on we had OTB and Big boats on the same course and the handicaps aren’t even similar:

- The big boats TCF (time correction factor) higher = faster and a big number is 1.2

- The OTB Yardstick LOWER = faster and a big number is 130?

How does that work?

Maths my friend Maths. 

You know the RL 24 Rumline? Well you probably don’t but it has raced as a Trailer Sailor and has a PHS number, Its an RL24 SK (Swing Keel) and that design as (had) has an AY (Australian Yardstick). 

So we work out the ratio between a OTB Yardstick and that of an RL24 SK and then multiply that by the PHS Number of Rumline and bingo. 

Of course if you can come up with a better way then we should do that and I resign. (Oh I did that two years back) 

Any yes there are many, many other ways to poison the handicap well, but remember a race with messed up results doesn't just mess up that race we live in the age of computers it messes up future races too.

*I for one welcome our robot overlords..... 

I, like Fred, have written software, its not as good has his but it is here

(I resign)