IOR v todays boats

Originally posted by laser193713 (Carkeek 40) is in Class 0. IRC rating 1.267. There is an Elan 40 from 2004 in Class 4 at 1.025 and the rating list for the NZ 1 ton Revisited class begins at 0.926 for what I can only presume is a non updated boat, some of them are much faster according to IRC which means they must have been optimised and modernised.

What it really means is the Carkeek 40 is a big dayboat with zero possible after-life as a cruiser and which you'd be bonkers to race offshore.

The NZ 1 ton class allows boats from different IOR eras e.g. IOR 27.5 and 30.5 foot raters. That may explain some of the differences in IRC ratings. Remember also these boats have benefit of shed-loads of age allowance so comparing them to a modern IRC hull and design is somewhat misleading.

I'm not saying that a modern IRC or ORC optimised 40 footer isn't significantly quicker than a late period IOR one tonner but the difference isn't as large as you are suggesting.





Edited by blueboy - 22 Aug 15 at 12:30pm

They are much wetter boats these days though, and much less comfortable. Remember, the physics of sailing haven't changed, these boats just don't carry around a library of almanacs and beautiful teak galleys. Many of the 1 tonners had all of this. The materials available these days maybe account for 5% of the performance improvement. If you took a mould of an old IOR special and made it in new materials with carbon masts and sails etc that is all you would gain. What the materials do allow is much wider boats, much lighter boats and much less drag from foils and spars and rigging. The biggest differences are in light wind performance and downwind performance. This is why so many people thing that modern boats are dog slow upwind. Just because the beats take 20 minutes and the runs are taking 5 minutes for some of the classes these days doesn't mean they are slow upwind, it just shows how fast we can get boats going downwind these days. 

Round the island now takes around 5 hours, rather than 7 ish for a 40 footer... Good enough?

Edited by laser193713 - 13 Aug 15 at 12:07pm