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F18 mast position with spinny up

Posted By: waynemarlow

F18 mast position with spinny up - 05/03/15 03:02 PM

Not having owned an F18 before, where is everyone putting the mast rotation when the spinny is up. Coming from using an A class mast where one simply lets off the mast rotation and the mast generally goes fully out and that is considered to be the strongest axis for the mast, is the F18 any different ?

Some at my club are saying that the mast shouldn't be let out significantly from the upwind position but my worry is that should on A Class terms put the mast into its weakest position. Am I correct on this.

Thanks
Posted By: Karl_Brogger

Re: F18 mast position with spinny up - 05/03/15 03:57 PM

You let it out all the way.
Posted By: Todd_Sails

Re: F18 mast position with spinny up - 05/03/15 07:30 PM

Agree with Karl, ^ he peaks catamaran.

Karl, I hope to see you at Rock lake Memorail weekend?
Are you in the GT300 this year?
I'll be there WITH my 1/2 ton truck! ;-)

Posted By: David Ingram

Re: F18 mast position with spinny up - 05/03/15 11:15 PM

The above comments are correct and present the strongest profile to the loads being applied by the spinnaker but are not necessarily the fastest. This has been hinted at by comments related to mast breakage with the N17 and even Macca made a comment that you trim the mast rotation to the mainsail trim. So... how bad do you want to win and are you willing to replace your mast and mainsail?
Posted By: Anonymous

Re: F18 mast position with spinny up - 05/03/15 11:45 PM

^^^ What he said^^^

90 degrees is safe, around 60 degrees is fast. You'll need to experiment and adjust to find what is right for the boat and conditions.

Same goes with your main sheet. Firm and cleated is safe, constantly played is fast.
Posted By: waynemarlow

Re: F18 mast position with spinny up - 05/04/15 03:39 PM

Thanks guys, just thought I may have the wrong settings, but our letting full out is in that 60 - 90 degree range so we are'nt far off.

I've been playing travellor rather than main sheet, simply cleating the main at just off upwind tensions and letting the tell tails dictate the travellor settings.

Our courses are so short and congested with slower boats that sometimes it just better to get my head out of the boat and sail on a set tension than to bother to try and adjust all of the time.
Posted By: Karl_Brogger

Re: F18 mast position with spinny up - 05/04/15 04:57 PM

The problem with dropping traveller is that you aren't really changing the shape of the sail, just the angle of attack. Another issue is that you are presenting more sail to the wind coming from behind if you stuff it and the apparent wind comes around. You're actually compounding the problem of putting more pressure on the bows. Easing the main will open up the top too, but you're also changing the shape of the sail through the middle to a more powerful shape, which can help pull you out of the bows plowing through the water scenario and get moving again..

You should pretty much just be dropping off traveller to reach up, like if you're overstood, and can't carry the angle you need to make the mark. Being a singlehander, I don't trim the main downwind unless it's really out of shape.
Posted By: John Williams

Re: F18 mast position with spinny up - 05/06/15 01:07 AM

Think of the traveller as a gross adjustment and the mainsheet as a fine adjustment. You really will go faster trimming the main - unless you're surviving or overstood (violates Kirk's First Commandment of Catamaran Racing - thou shalt not overstand the gate), the traveller is a crutch... and crutches ain't fast.
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