IRC yacht ratings for comparison of boat speed.

[fishermantwo]

Couple of days ago I was having a chat with a mate and we got to comparing our yachts. I own a Ben Lexen quarter tonner, he owns a Compass 28, long keel Australian yacht built in large numbers. He made the comment that while its a good boat it tends to be slow when actually going some place. This started me thinking about comparing stock production cruisers. I stumbled on to the IRC web page which had an interesting bit where it explained that the difference of 0.001 works out to be roughly 3.6 seconds per hour for boats with ratings about 1.000. Slower boats around .700 works out to be closer to 4 seconds per hour.
This is fine for the boats that I know the IRC ratings for, what I need now is more web sites that list production ratings. Any other interesting rating stuff appreciated. Australian and international.

 

[halcyon]

Try the following site.

http://www.byronsoftware.org.uk/bycn/byspeed.htm

Brian

 

[gandy]

Or the CYCA handicaps, here. CYCA numbers are the number of minutes start that a boat would need for a one-hour race. Maybe someone else could explain that better.

http://www.cyca-online.org.uk/

 

[moondancer]

IRC is a good indicator but there are 2 drawbacks. Firstly there is not, as far as I am aware, a public list of vessels and their IRC rating. The closest that I have been able to get to it is by going through race results and then looking at the IRC ratings of the boat lists in those races. If you do this for a few races you can get a good view of most boats ratings.

The other factor is that an IRC rating relates to an individual boat not a particular make/model. Over the course of a year our Malbec 240 demonstrator rated at 0.914, 0.908 and 0.903 depending on the sails used. There can be a fair bit of difference between two vessels of the same type.

IRC is better than PN in that IRC aims to give a pure view of the performance of the boat and makes no allowance for the capability of the crew. PN is a handicap based on race results and also allows for crew performance as well.

 

[fishermantwo]

[ QUOTE ]
IRC is a good indicator but there are 2 drawbacks. Firstly there is not, as far as I am aware, a public list of vessels and their IRC rating. The closest that I have been able to get to it is by going through race results and then looking at the IRC ratings of the boat lists in those races. If you do this for a few races you can get a good view of most boats ratings.

The other factor is that an IRC rating relates to an individual boat not a particular make/model. Over the course of a year our Malbec 240 demonstrator rated at 0.914, 0.908 and 0.903 depending on the sails used.

[/ QUOTE ]

Thanks for that. I noticed when I checked club web pages that various production cruisers had different ratings and probably for the reasons you mentioned. Interpolating those figures gives a pretty good indication of the boats speed and has been very enlightening. Interesting how the mass produced boats in the various ton classes now have different ratings, some are more equal than others. They may have been built to a ton rule and theoretically racing on equal terms but some have turned out faster than others. Some of these obviously lend themselves to later modifications after the demise of the ton classes, different keels, taller masts etc.

The object of my exercise though was to find out the real difference between the old style production long keeler like my mates versus all those production fin keelers that I would likely update to. To this end the IRC seems to be the easiest to work with taking into consideration the points you raised.