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us7070

J133 IRC ratings

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I assume there is a simple answer to this...,

 

USA;

 

Sirensong: 1.1470

Antidote: 1.1480

Bachanal: 1.1490

 

From American YC Spring Regatta scratch sheet (2007)

 

UK;

 

JB 3: 1.113

Jivaro 1.13

Jellina 1.109

Black Jack 1.126

Jacana 1.108

Jump 1.119

 

From 2007 Cowes-Dinard-St Malo Race

 

 

What's going on?

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I thought that, but 0.030 is quite a big difference. If the UK boats just use 100% gennys and the seppo ones have 155s that migh do it

 

Another UK (Northern Ireland) based number "Spirit of Jacana" 1.118

Having raced with them on and off over the last 2 years, they only have non overlapping headsails.

And from racing at the J-Cup in Plymouth the other week. Jump was on the same sailplan as us at 1.119 and Jellina was using a roller non-overlap at 1.109

 

Steve

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Its looks as though the weighed (Endorsed) European boats are slightly heavier than those weighed in the US, I am told this is due to difference in interiors.

i.e. Antidote in the USA is 8447kg & J B 3 in the UK is 9342kg

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Another UK (Northern Ireland) based number "Spirit of Jacana" 1.118

Having raced with them on and off over the last 2 years, they only have non overlapping headsails.

And from racing at the J-Cup in Plymouth the other week. Jump was on the same sailplan as us at 1.119 and Jellina was using a roller non-overlap at 1.109

 

Steve

 

 

interesting...

 

they seem to do very well w.r.t the rating under this sail plan.

 

of course maybe they can get a way with it because the UK is (generally) breezier than western LIS, where the US boats are located.

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That US list may not be completely up to date. One boat in that US list has had its upper spreaders shortened by 3"; also differences between jibs. Can't comment on the US vs. UK ratings.

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Its looks as though the weighed (Endorsed) European boats are slightly heavier than those weighed in the US, I am told this is due to difference in interiors.

i.e. Antidote in the USA is 8447kg & J B 3 in the UK is 9342kg

Yes, I think it's the J/133s where the French built boats are quite substantially heavier than the US built ones.

 

(not in the office this week)

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Yes, I think it's the J/133s where the French built boats are quite substantially heavier than the US built ones.

 

(not in the office this week)

My understanding is that Jump [uk boat] is american built and is 600Kg lighter, but that doesn't account for the rating difference

 

maybe gravity is heavier in the UK, or perhaps the water is more dense - that must be it, it's the water density

 

Jen?

 

J

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I should know more about this as I race on Jammy Dodger IRC 1.115 , but as far as i know the US built boats are lighter, and they use larger overlapping headsails rather than our 105% ones.

Obviously we need a little more wind to power the boat up but anything over about 8 kts TWS is enough too drive us upwind at 6. something and that is a low mean for Uk average wind speed.

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My understanding is that Jump [uk boat] is american built and is 600Kg lighter, but that doesn't account for the rating difference

 

maybe gravity is heavier in the UK, or perhaps the water is more dense - that must be it, it's the water density

 

Jen?

 

J

In fact scratch my last post Jem is right! the water here is much saltier so we float higher thus shorter water line length..

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I should know more about this as I race on Jammy Dodger IRC 1.115 , but as far as i know the US built boats are lighter, and they use larger overlapping headsails rather than our 105% ones.

Obviously we need a little more wind to power the boat up but anything over about 8 kts TWS is enough too drive us upwind at 6. something and that is a low mean for Uk average wind speed.

 

it's clearly not just weight - must be a different sail plan

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Spirit of Jacana and Jump are both US built.

 

I know the French built boats like Jelina (I think) and Jammy Dodger are significantly heavier as the French believe there is a benefit on IRC here without significant performance drops.

 

Sheeting on the main is different (German on European funny enough) and the Euro crop typically have carbon booms and discontinuous rigging, but sail plans, rig sizes and anything else I can think of are the same (apart from a nice machined aluminium table leg with J in it!!).

 

Some of this equates to a couple of points in favour of the Euro boats but is not reflected in either results or performance to any degree.

 

The 30 point difference I cannot explain.

 

The first Euro boat was Jeronimo which had (I believe) a taller rig, deeper keel, bigger bulb (of sorts) and more sail but she was always rated higher. Unless the US guys are buying this option from France but I doubt it.

 

WTM

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Canadian boat I've sailed on has 175 sqm chutes and 155% gennies and rates 1.150. We reckoned that with the A/C, hot water, inverters, back-up batteries etc. we were looking at 20,000 lbs in sailing trim. It had a carbon spar. God (or the Johnston bros) only knows about the weight difference issues. It seems a bit of a shambles in my view, but I don't know what the class thinks, if there is a class organization.

 

The 133s I saw at the J-Cup, all had direct-to-winch mainsail sheeting and overalpping sails (Plymouth was a drifter).

 

Not sure about mainsail size but is this a sensitive measurement in IRC? Seems a mystery to me why the NA boats are so much "faster" as far as IRC is concerned.

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maybe gravity is heavier in the UK, or perhaps the water is more dense - that must be it, it's the water density

 

The beer certainly is and that's got to come from somwhere.

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This is what copy certificates were invented for... £10 each (limited to 5 of any single design).

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Yes, I think it's the J/133s where the French built boats are quite substantially heavier than the US built ones.

 

(not in the office this week)

My understanding is that Jump [uk boat] is american built and is 600Kg lighter, but that doesn't account for the rating difference

 

maybe gravity is heavier in the UK, or perhaps the water is more dense - that must be it, it's the water density

 

Jen?

 

J

 

don't forget Jump was the first 133 in the UK i think? has the sail number GBR133R

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Yep Jump was built in the USA but she had non overlapping headsails and smaller kites, even smaller than the European built 133s which were considerably heavier

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