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mainsheet tension #181944
06/14/09 12:25 PM
06/14/09 12:25 PM
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pgp Offline OP
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How much is too much? I've had two friends, both A Class sailors, tell me I need to sheet my main harder. So, are the two boats similar in this regard? I would say I'm already sheeting hard though certainly not "block to block". It's possible I'm using too much luff tension.

Secondly, Stefan at 75 kb. thinks we could have been double trapped yesterday (I only have the single trap fitted becuase I usually sail uni.) in 12-15knots. Our combined weight is 180 kgs. I'm afraid that if we double trap and "sheet the hell out of it" I'll break something, namely the mast.

I have to say sailing with Stefan is a hoot! The guy has so much energy and is so positive!


Last edited by pgp; 06/14/09 12:31 PM.

Pete Pollard
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Re: mainsheet tension [Re: pgp] #181947
06/14/09 12:51 PM
06/14/09 12:51 PM
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Timbo Offline
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Pete, you might break something but it won't be the mast. It will flex and bend but that's what it's supposed to do. Remember though, as you are sheeting extra hard and with 2 on the wire, you are putting a lot of stress on the fore stay, and the jib halyard, so be sure you look those over when you are rigging it up.

You can break your jib halyard if you don't adjust it for correct luff tension with the main sheeted on hard. The easiest way to break it is to tighten it up real tight while the main is real loose, like at the end of the run, or on your way out to the starting line, spin up, mast is being pulled foreward, you tighten up the jib halyard getting ready for the upwind work...but...after you snuff the spin and sheet in the main, and put two on the wire, you will have moved the mast backwards, and you can really be over-done on the jib halyard, so be careful.

Don't ask me how I know.


Blade F16
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Re: mainsheet tension [Re: Timbo] #181951
06/14/09 01:35 PM
06/14/09 01:35 PM
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Pete

As timbo says, be carefull tensioning the Jib halyard.

As for wind speed and 2 trapping, 15 kts you should be de-powering !!!!

Something very wrong here.

How much pre-bend do you have on?

what purchase do you have on your main sheet?

How hard are you sheeting in?




F16 - GBR 553 - SOLD

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Re: mainsheet tension [Re: pgp] #181953
06/14/09 01:57 PM
06/14/09 01:57 PM
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the tension from the mainsheet translates to the forestay. Max mainsheet tension, 2 dudes on the wire at the back of the boat and you hear a crunch. It will be the bows pulling together due to the angle of the forestay bridle. Been there...

you should maximally sheet the mainsheet although it can be over done. I find that lots of mainsheet tension and trav down a tad is faster than trav midline and slightly off on the mainsheet.

Last edited by PTP; 06/14/09 02:00 PM.
Re: mainsheet tension [Re: pgp] #181954
06/14/09 02:15 PM
06/14/09 02:15 PM
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Hamburg
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For two up sailing, you should have 3mm or better 4mm shrouds and the part of the forestay, which is above the jib luff should be 4mm minimum, the lower part might be 3mm. The shakels 6mm at least. That`s what you find of most double handers. With hulls and mast designed for two, it shouldn´t be a problem.

The main is hard enough, if the leech stands up straight, even with the downhaul on. That`s universal for all sailboats.

Cheers,

Klaus

Re: mainsheet tension [Re: pgp] #181973
06/15/09 01:59 AM
06/15/09 01:59 AM
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Mumbles Y.C Wales U.K
Mark P Offline
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I can't really discuss 2 up but when 1 up I sheet as hard as I can when I can. This usually means until I physically can't pull any more. The sail is as tight as it can go, if I am then constantly bearing up in the gusts or having to ease the main then I pull some more downhaul on still trying to keep maximum pressure on the mainsheet. This technique is only used in medium wind conditions and I all ways try to remember to ease to the downhaul just prior to rounding the windward mark just to save the sail from over stretching the luff. However, I do forget occasionally ;-(

Last edited by Mark P; 06/15/09 02:00 AM.

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Re: mainsheet tension [Re: scooby_simon] #181974
06/15/09 04:32 AM
06/15/09 04:32 AM
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pgp Offline OP
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Originally Posted by scooby_simon
Pete

As timbo says, be carefull tensioning the Jib halyard.

As for wind speed and 2 trapping, 15 kts you should be de-powering !!!!

Something very wrong here.

How much pre-bend do you have on?

what purchase do you have on your main sheet?

How hard are you sheeting in?




Prebend is still to factory setting, whatever that is. 6:1 on the main. I think the next outing there will be very little downhaul.

With 180kgs trapped out, I'd think we'd need full power. But what about rotation? 20-30 degrees? Also, it's probably time for a split-tail main sheet.

Last edited by pgp; 06/15/09 04:33 AM.

Pete Pollard
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Re: mainsheet tension [Re: pgp] #181976
06/15/09 04:50 AM
06/15/09 04:50 AM
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Wouter Offline
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Quote

With 180kgs trapped out, I'd think we'd need full power. But what about rotation? 20-30 degrees? Also, it's probably time for a split-tail main sheet.


Personally, I feel that double trapping with 180 kg on the wire in not something the F16's are designed to do. Any well designed F16 should be able to handle any loads that sailing can put it under ; it is just that I don't think that much righting moment balances well with the flexing of the mast.

At some point, high mainsheet tension will only reduce the draft of the sail while also when straighten the leech. These two effects oppose one another in the feel of power. I believe you feel just as powered up but the craft is overall slower just the same.

I feel sailing that F16's (and yes I'm not a world champ) is more about getting the draft profile and twist profile right then about keeping 2 men on the wire. You trim the sail for maximal drive / speed and you go in or out of the trapeze to maintain that sail trim.

Now I don't feel that unless you sail is cut for 180 kg that you can keep 180 kg on the wire and still have the optimal sail trim for performance.

Basically at 180 kg you have 120% the righting moment then a 145 kg crew trapping. If your sail is cut of say 145 kg then going single trap with reduce the overall righting moment to 105% of the 145 kg crew. It is my believe that this matches the shape cut into the sail much better and you'll probably be sailing with a little more draft and a better twist profile.

This has also been my experience on my own boat. Agreed my mainsail has an error up top, but it just performed better with me hiking and my 70 kg crew trapping then when we both went to the trapeze. Back in the time of these experience I was about 90 kg.

Wouter


Wouter Hijink
Formula 16 NED 243 (one-off; homebuild)
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Re: mainsheet tension [Re: pgp] #181978
06/15/09 05:06 AM
06/15/09 05:06 AM
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scooby_simon Offline
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Originally Posted by pgp
Originally Posted by scooby_simon
Pete

As timbo says, be carefull tensioning the Jib halyard.

As for wind speed and 2 trapping, 15 kts you should be de-powering !!!!

Something very wrong here.

How much pre-bend do you have on?

what purchase do you have on your main sheet?

How hard are you sheeting in?




Prebend is still to factory setting, whatever that is. 6:1 on the main. I think the next outing there will be very little downhaul.

With 180kgs trapped out, I'd think we'd need full power. But what about rotation? 20-30 degrees? Also, it's probably time for a split-tail main sheet.


Pete,

You need to find a tune-sheet for your mast. with a 6:1 I'd suggest you need to pull real hard. but not over sheet. Time to scatter some tell-tails over your sail. I'd start witha like of about 4 about middle of the sail for the top coupe of panels and then about 60-90cm from the luff and also a settof leach teltails. I would also stick some teltails on your mast!

I would also think you do not need much pre-bend, but still plenty of tension in the diamonds to get some power in the rig!


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Re: mainsheet tension [Re: Wouter] #181981
06/15/09 05:17 AM
06/15/09 05:17 AM
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West coast of Norway
Rolf_Nilsen Offline

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Pete,

if you lack upwind speed/VMG, listen to your friends. If not.. smile
They are in a better position to study your leech than you are. If you dont sheet hard enough, you dont have the pedal floored, and if you are racing, you want .
If you are in doubt wether you have enough sheet on, look at the telltales. Are they streaming? What happens if you sheet the main a bit harder, still streaming? Sheet in until they stall, then let out until they stream again. Have your crew on the main and let him work the sheet to the above rule all the time while you focus on the water and helming the boat fast. You probably need more sheet tension than you think, but your telltales will help you, if you look at them that is. I dont like to have too many telltales on the sail/rig. That is just confusing in my experience, and you end up using just a couple of them anyway. Your main probably came with all the telltales you need.

If you have too much or not enough donwhaul on, the boat will be slower than it could be. The only way to tell is to look at the boats around you and spend time in the boat so you get the feel for it. If there are other boats with similar sails/masts and crew weights around, ask about their settings after the race. In 15 knots you probably want the downhaul on quite firmly for best speed.


I would listen to mye friends when telling me that I was not sheeting hard enough for the conditions.

Re: mainsheet tension [Re: Rolf_Nilsen] #181982
06/15/09 05:25 AM
06/15/09 05:25 AM
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pgp Offline OP
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smile I have whip marks across the tops of my thighs! That's from Stefan popping me while sheeting in and out! Part of the confusion is that I'm driving the boat hard and not doing much else. That's Stefan's job!

It's all good! We'll give it another go this weekend in Daytona. If we can get through the surf! wink


Pete Pollard
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Re: mainsheet tension [Re: pgp] #181983
06/15/09 05:37 AM
06/15/09 05:37 AM
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Pete,

DO NOT buy a new sail, for one thing, baggy/full sails do NOT work!! They are dog slow. Just ask people who have done sail development programmes!

You will suffer in the ligher wind speeds, but I would still expect you to be fully/over powered in 15kts (top F4).

As Rolf says, get people to sail behind you and look at the leach profile and how the sails are setting. you should be well powered up in 15 kts!!!

Next time youy are at the boat, take some pictures with the sail up to show us...

Last edited by scooby_simon; 06/15/09 05:44 AM.

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Re: mainsheet tension [Re: pgp] #181984
06/15/09 05:41 AM
06/15/09 05:41 AM
Joined: May 2003
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West coast of Norway
Rolf_Nilsen Offline

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Two other items I would like to comment on:

1: Twist.. In chop twist is faster in my experience. In weak winds, twist might be faster, in strong winds, you will not be able to sheet hard enough to remove the twist anyway smile (mast bends, sailcloth is flexible etc.)

2: Sail design and custom sails for crew weight, dominant conditions, skill level etc.. Dont bother, go with what you have or the class "standard". The margins are so small and the risk of actually buying a slower sail than the class standard is pretty large.

Keep it simple. Simple is fast smile


Good luck in Daytona. Hope you and Stefan get a few hours on the water to practice your boathandling and teamwork before the regatta.

(PS: During strong wind regattas my crew, Frode, sometimes bent his legs and sheeted in by straightening the legs with a stiff body and a super-firm grip. That was with a 1:9 purchase on a Tornado rig. Then he began using his arms and back for small adjustments. Just to give you an indication on how much sheet tension we used at times. Not saying that you want to do this even if we did. We are/was not world class sailors)

Re: mainsheet tension [Re: Rolf_Nilsen] #183150
06/26/09 06:56 AM
06/26/09 06:56 AM
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pgp Offline OP
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We had a blast at Daytona!

BTW, the advice is unanimous; from A Class to N20, everyone sheets much harder than I. Of course, I'm not Stefan! He sheets the hell out of the boat! shocked (and it works!)

So what are the tecnical requirements, especially sailing Uni? Who uses 8:1 blocks? 10:1? Is a tapered main essential? I'm certain a split tail is necessary, as is, the whole traveler car jumps around making sheeting that much more difficult.

Last edited by pgp; 06/26/09 06:58 AM.

Pete Pollard
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Re: mainsheet tension [Re: pgp] #183153
06/26/09 07:18 AM
06/26/09 07:18 AM
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France
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I recently converted from 6:1 to 7:1. It was really easy to do, I just added a spring supported block where the sheet used to finish on the bottom block, and attached the sheet to the unused bracket on the top block. I had to get a longer sheet however, but I reused an old spi sheet I had.

7:1 is better than 6:1, I can get it tighter with one hand that I use to be, and that's an improvement upwind. I think 8:1 would be too much rope to pull. I'm now going to reduce the amount of sheet needed by making a tail to lower the top block and then probably make a taper.

I made myself a poor man split tail (a dyneema loop on one side, the traveler line goes through the loop and attach to the other side). To have the car not move at all when you sheet in was a good improvement.

Re: mainsheet tension [Re: pgp] #183155
06/26/09 07:26 AM
06/26/09 07:26 AM
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West coast of Norway
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Cool! Sounds like you have had a revelation smile
What kind of windstrength did you have at Daytona?

About split tails. They are useful for centering the car, but the car will still move a little bit even with a split tail.

Any friction removed gives you exactly that much more power to sheet in the main with. Tapered sheets reduces friction. Cascade in-boom sheeting might remove even more friction.
If you are not strong enough to sheet hard, more purchase and some strength training is your friend. Adding ridicilous amounts of purchase have its drawbacks!

If you are serious about wanting to sheet harder and your present setuo dont work for you:
1: I would look at the sheeting technique and setups used in the A-class since you have them close to you. Ask the guys how they do it and learn their technique before changing your boat.
2: Begin working out to gain strength (working out is free, so the price is right).

Did I piss you off now?

Re: mainsheet tension [Re: Rolf_Nilsen] #183160
06/26/09 07:34 AM
06/26/09 07:34 AM
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pgp Offline OP
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Originally Posted by Rolf_Nilsen
Cool! Sounds like you have had a revelation smile
What kind of windstrength did you have at Daytona?

About split tails. They are useful for centering the car, but the car will still move a little bit even with a split tail.

Any friction removed gives you exactly that much more power to sheet in the main with. Tapered sheets reduces friction. Cascade in-boom sheeting might remove even more friction.
If you are not strong enough to sheet hard, more purchase and some strength training is your friend. Adding ridicilous amounts of purchase have its drawbacks!

If you are serious about wanting to sheet harder and your present setuo dont work for you:
1: I would look at the sheeting technique and setups used in the A-class since you have them close to you. Ask the guys how they do it and learn their technique before changing your boat.
2: Begin working out to gain strength (working out is free, so the price is right).

Did I piss you off now?


smile No you didn't piss me off! The wind at Daytona was mostly 8-10, sometimes a little lighter. We were getting some crazy puffs that were not so much stronger, but Changed direction severely. Trying to keep speed and come up with the lift, I almost went over once.

Pepin: I'll try your poor man's split tail as my splicing skills are non existant! And now that you mention it, I think I already have the 7:1. It was standard on the boat and I changed it out for light air work and never went back to it! blush

Last edited by pgp; 06/26/09 07:37 AM.

Pete Pollard
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Re: mainsheet tension [Re: pgp] #183161
06/26/09 07:44 AM
06/26/09 07:44 AM
Joined: May 2003
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West coast of Norway
Rolf_Nilsen Offline

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Pete,

there are many ways of making a split tail without splicing. Be creative and get a large needle+sailmakers glove. If nothing else, stitching the tail to the traveller line will do the trick, even if it is a but crude. Pulling the cover of the control line back, then stitching the tail on in different ways is also feasible. Think a bit ahead then Get To It smile


Did you see the gusts coming? Instead of coming up in short blasts, how about sheeting a bit out and sailing through them with greater speed? Depends on conditions of course.

Re: mainsheet tension [Re: Rolf_Nilsen] #183165
06/26/09 08:15 AM
06/26/09 08:15 AM
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pgp Offline OP
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Yes, we could see the gusts coming. I have a clear memory of, not sheeting out, but falling off a bit and going through with greater speed; and watching Matt/Gina as well as both Tigers climb W-A-A-A-Y above us! In this case the gust was usually a huge lift.

laugh Wait! That can't be right!?? (so much for clear memory)!

Maybe Matt will give us his version. He and G. seemed to really take advantage of them.

Last edited by pgp; 06/26/09 08:23 AM.

Pete Pollard
Blade 702

'When you have a lot of things to do, it's best to get your nap out of the way first.

Re: mainsheet tension [Re: pgp] #183180
06/26/09 09:41 AM
06/26/09 09:41 AM
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Hamburg
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Hi Pete,

the best way for me to know how hard to sheet, is the usage of tell-tales on the leech of the sail. If only the top one are absorbt, you sheet to hard. If the low one are absorbt you don't sheet enough. I had to learn that I have to use the proper rotation for a wing mast as well. A wing mast needs to point much more in the direction of the boom than a conventional mast and this will close the top of sail as well. I use the "poor man's split tail" as well and it is absolutly sufficient, but not as nice looking as a true splice.

Cheers,

Klaus

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