Fast boats and slow boats

[flaming]

I've just noticed that it was a Farr 31, not a 30. It's the 30 that I was thinking of, a Farr31 is (I'm pretty sure) an old IOR design, not a downwind flying machine.
Which probably means PHRF was it's best option.

And I was close, an IMS design from 1994.

http://www.farrdesign.com/321.htm

 

[dt4134]

I've just noticed that it was a Farr 31, not a 30. It's the 30 that I was thinking of, a Farr31 is (I'm pretty sure) an old IOR design, not a downwind flying machine.
Which probably means PHRF was it's best option.

I presume it is one of these. http://www.farrdesign.com/321.htm

Still, it does mention CHS...

 

[dt4134]

You beat me to it.

 

[Bosun Higgs]

Looking at PHRF handicap ratings, the difference between a fast boat and a slow boat is not that big at all. Looking at boats of a similar size

FARR 31 81
X102 120
BENETEAU OCEANIS 321 168
CONTESSA 32 180
ISLAND PACKET 320 198

This means that the out and out racer, the Farr would be about 2 minutes per mile faster than the Island Packet (198-81). In normal conditions, say the Island packet is going 5 knots, that would be about (5 * 2/60 miles=) 1/6 mile, just under 300 meters, after an hour's sailing. Part of the Farr's advantage is probably pointing ability, so on most points of sail, the difference would be even less.

Considering the very different emphasis in design, I find the gap surprisingly small.

Perhaps more surprising is the miniscule difference between the Island Packet 320 and the Contessa 32. The former being 6.1 tonnes, chubby and long keeled - the latter being 4.2 tonnes, pointy, sleek and deep fin keeled. The difference is only 18 seconds per mile, or after an hour at 5 knots, they'd be only 45 meters apart.

(source of ratings: http://www.phrfne.org/page/handicapping/base_handicaps)

I was surprised to see that the PHRF handicap can be run as a time on distance calculation since it means that the allowance for the speed of a faster boat gets effectively bigger as the wind dies and sailing speeds get slower.

If you use the time on time handicap systems such as the PY or the IRC, then the difference between a Farr 31 and an IP320 is 18% or put it another way, when the Farr is averaging 6 knots, the IP will be averaging 5.1.

That said, most of us dont go sailing to get somewhere fast. If we did we would use a mobo. Instead we go sailing to enjoy the sailing, and this is the biggest difference between boats maximised as caravans like the IP and maximised for speed like the Farr. My Volvo car is as fast in a straight line as my Lotus, but one is fun to drive and the other is made by a truck manufacturer.

 

[DownWest]

[. My Volvo car is as fast in a straight line as my Lotus, but one is fun to drive and the other is made by a truck manufacturer. Great comment. Which Lotus?
a

 

[awol]

If you use the time on time handicap systems such as the PY or the IRC, then the difference between a Farr 31 and an IP320 is 18% or put it another way, when the Farr is averaging 6 knots, the IP will be averaging 5.1.

... and if you do the PHRF arithmetic correctly 2 minutes per mile handicap with the Farr averaging 6kts should put the IP320 12 minutes behind after 1 hour or 1nm at 5kts which is, within a ba' hair, the same.