Jib vs. genoa in VERY light air

Sail trim, rig tuning, and related topics.

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chris_z
Posts: 46
Joined: Wed Dec 31, 1969 8:00 pm

Post by chris_z »

Was reading an interesting thread on the Sailing Anarchy forum yesterday regarding which headsail to use in VERY light air (0-4 knots). The theory was that using the jib was better than the genoa because it would keep better airflow (such as it is at 2 knots) going as it would not be flapping around like the genoa does.

Any thoughts? The last few Wednesday night races have been real drifters, looking for a little more boatspeed upwind. Downwind is fine, we sail the asym like a gennaker on a close reach and scream by the other boats.
bslick
Posts: 11
Joined: Wed Dec 31, 1969 8:00 pm

Post by bslick »

Last night was one of those races, 3 knots true wind. We sailed the boat low and loose. The genoa was out side the life lines. We were 7 minutes ahead of the second boat. The jib likely would have had better shape allowing us to point high but in that light of air hi is slow. Anything under 15 true #1 is, and always will be my sail.
chris_z
Posts: 46
Joined: Wed Dec 31, 1969 8:00 pm

Post by chris_z »

Yeah, we were sailing at anywhere from 50-55 degrees off the true wind, everything fat and happy to keep the boat moving. Wind read 2.4 knots, boat was moving thru the water at 2.6, so I cannot complain too much!!!
alex
Posts: 5
Joined: Wed Dec 31, 1969 8:00 pm

Post by alex »

Hey there,
I was reading your thread about Genoa vs Jib.
When you talk about n.1 what do you refere to? You mean the class n.1 Genoa, which, if i'm not mistaken is a 105% of the J, or you refer to something larger?
Here in Italy we don't have many 109s so we race in IMS (very bad rating due mainly to the asim), and use a big 140% Genoa on a furler.
My question is: how much speed do you loose by using a 105% instead of a 140% in light air?
What, in you opinion, is the windspeed at which the two sails are equivalent?
Thanks for any indication.
Alessandro
chris_z
Posts: 46
Joined: Wed Dec 31, 1969 8:00 pm

Post by chris_z »

Alessandro,

We only get to do one or two one-design events a year, the other 40 or so races we do each year are handicapped races, either PHRF or IRC.

For our boat, the #1 is a 155% genoa. We have two, one for light wind (0-8 knots) and the other for medium/heavy (8-15 knots).

If we keep doing a lot of PHRF we will add a #2 in the form of a 125%, which will cover the puffy conditions we often get here (10 knots in the lulls, then a gust for 5-20 seconds of 15-20 knots).

Our #3 is the class 105% jib, it is very heavy duty, made of carbon with a double-sided taffeta covering. The thing is pretty strong, and we use it when we know it will be 15 knots and building.

We have never used a 140, so I can't tell you the speed drop-off from the 140 to the 105, but a couple of times we got the forecast wrong (or the wind was different out on the race course than it was in the harbor, and we showed up in 5-8 knots of breeze with the 105. We got KILLED by the other boats around us with 155s, they all rolled us and took off like we were standing still.

For us, the crossover point is usually 12-15 knots. At that point the 155 Genoa is generating too much power, and we seem to get better VMG with the 105.

Of course, being from Italy I am sure you know much more about Genoa's than we do here in the states.

Sail Fast!

Z
alex
Posts: 5
Joined: Wed Dec 31, 1969 8:00 pm

Post by alex »

Chris,
thanks, that's very clear+usefull.
As you can imagine I am completely new to handicapped racing, and was very envyous of the one-design 109 competition I thought you had all around the US. Well, at least I'm not alone, it seems.

One problem we have with the IMS handicap rule here is that, since we use a furler, we can only use one haeadsail, in our case the 140% Genoa we registered. The only sensible option in windy conditions would then be to reduce the mainsail, no matter what. We haven't tried yet with strong wind, but it sounds a bit strange.
Probably, getting our handicap given on a 125% Genoa would be a better allround bet for IMS racing.
Or we will only participate toIRC events (not many in the Northern Mediterranean). There is no such limitation with the IRC rule, is there?
Thanks again for your precious help, and ciao from Genoa (yes I'm from Genoa, Italy!)
Ale
chris_z
Posts: 46
Joined: Wed Dec 31, 1969 8:00 pm

Post by chris_z »

Alessandro,

I am surprised IMS only lets you use one headsail. In IRC (like PHRF), your rating is determined by your LARGEST headsail, but if you want to, you can use a smaller sail. I Don't know the IMS rules all that well, but I know that rule 205 defines how many sails you can carry while racing. Even if you use a furler, you can still do a headsail change if you need to. We usually do ours downwind. When we reach to windward mark and set the spinnaker, we drop the headsail. We then fold it up, bring it below and bring up the new sail. Then, when it is time to douse the spinnaker we hoist the new headsail and then do the douse.

Check into the rules, I would think it would be dangerous to sail with only a 140, especially if a storm comes up and you have heavy (25-40 knots) winds.

Does anybody else here know IMS rules and restrictions on headsails due to roller furling?
alex
Posts: 5
Joined: Wed Dec 31, 1969 8:00 pm

Post by alex »

Chris,
thanks again.

I've looked into the IMS rule again.

"Appendix 9-Cruiser/Racer Heavy Items Pitch Gyradius Allowance Scheme", says that "....a gyradius increment of 0.0005*CANOEL will be credited PROVIDED THE FURLER IS USED IN ASSOCIATION WITH ONE HEADSAIL ONLY. ...".
This can be interpreted, but a fellow 109 italian owner told me he'd been disqualified in a race for changing headsail...

Now, I think the question still remaining would be: can one use only the specific genoa (140 in my case) which he's declared when registering in the simplified IMS scheme, OR
one can choose a smaller headsail at the beginning of the day and use that one, provided, one doesn't change it, during that particular race/day.

And another interesting question for which I miss an answer is: does the size of the credit you are given for using the furler justify the limitation that it implies?

I'll try to get some IMS answers also through other channels, so as to clear the questions for all in the Forum.
I don't want to create confusion here!
Thanks to all

Ale
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