spinnaker repair worth bothering with a new irc cert?

[apward]

After repair my spinnaker is smaller by 2.11 metres. Will that really reduce my irc rating?

Total area= 79.20 metres

rating office says. We cant really advise you. You'll have to pay to find out whether it does or not.

 

[Racecruiser]

After repair my spinnaker is smaller by 2.11 metres. Will that really reduce my irc rating?

Total area= 79.20 metres

rating office says. We cant really advise you. You'll have to pay to find out whether it does or not.

They won't say of course because it's a 'secret' rule although designers and sailmakers have a pretty good idea of what does what in rating terms. You can do a trial cert application to find out or leave it until renewal in 2016 - think I would talk to the sailmaker and see what he thinks will be the effect. Must be worth a couple of pips reduction I reckon.

 

[apward]

I have a big race in Aug so need to get the new cert now. -2 pips would be worth it. My guess is that No won't change. Anyone else have an idea?

 

[flaming]

I would expect you'll get at least a pip. Worth while having the other sails measured as well if your going down that route, laminates shrink with age.

 

[Triassic]

My understanding is that such a small reduction in the size of your spinnaker will have an almost insignificant impact on your rating. If however it was your mainsail it would be a different matter. When I first obtained a rating for my boat I noticed that it had a higher TCF than another boat of the same model, so I queried why. Bearing in mind I was rated at 1.185 and the other boat at 1.145, so that's a difference of only 0.040....... This is what I was told.

Triassic lighter weight (47kg), 0.010 = 27% of difference
Triassic larger spinnaker (1.67m2), 0.001 = 2.7% of difference
Triassic larger mainsail (2.4m2), 0.020 = 54% of difference
Triassic larger genoa 0.6m2, 0.006 = 16% of difference

So having a spinnaker that was 1.67m2 bigger was worth 0.001 on my rating.

 

[Racecruiser]

My understanding is that such a small reduction in the size of your spinnaker will have an almost insignificant impact on your rating. If however it was your mainsail it would be a different matter. When I first obtained a rating for my boat I noticed that it had a higher TCF than another boat of the same model, so I queried why. Bearing in mind I was rated at 1.185 and the other boat at 1.145, so that's a difference of only 0.040....... This is what I was told.

Triassic lighter weight (47kg), 0.010 = 27% of difference
Triassic larger spinnaker (1.67m2), 0.001 = 2.7% of difference
Triassic larger mainsail (2.4m2), 0.020 = 54% of difference
Triassic larger genoa 0.6m2, 0.006 = 16% of difference

So having a spinnaker that was 1.67m2 bigger was worth 0.001 on my rating.

I'm no expert on the IRC calculations and especially when it comes to multihulls - there could have been other factors like overhangs in the mix but what you say is consistent with one or two pips for Apward with his spinnaker coming down by 2.11 m2. We reckon each pip is worth around 3.5 - 4.0 secs per hour so if he gets a reduction of 2 pips that will be worth 21 - 24 seconds over a 3 hour race which could be worth having but is not so advantageous as doing everything right in the 3 hours!

Out of interest was it the rating office that told you about the %age differences?

 

[Triassic]

My rating is done by MOCRA, I think they have their own formula because as you say there are differences for multihulls, but I'm told they all work in a similar fashion. I know MOCRA have revised some of their workings because over the winter my rating went up to over 2...... and I didn't change a thing!

And yes, it was the rating officer that gave me those figures.

 

[apward]

Well the amendment has been applied for. Here's hoping for a reduction in pips. A few seasons ago my number went up between seasons without any measurement changes.

 

[apward]

After repair my spinnaker is smaller by 2.11 metres. Will that really reduce my irc rating?

Total area= 79.20 metres
.

The results are in.

The amended IRC rating reduces by just a single point.

 

[Racecruiser]

The results are in.

The amended IRC rating reduces by just a single point.

Shame it wasn't 2! Good luck with the big race ..........