Help me understand down wind on the tornado

hey guys, I was just watching the tornado finals on TV this afternoon and it was awesome. One of the things i noticed when the guys were sailing downwind with the kite up was that the skipper was playing the mainsheet quite a bit. This was especially clear in the footage of Ashby and Bundock going downwind. This is totally new to me as my focus has always been on the spin and treated the main as a sheet and forget. Can any tornado sailors enlighten me why the play the main so much?

Isn't the main supposed to be on tight so that the mast doesn't break from the strain of the kite? What are the skippers trimming to? the tell tales? Any info would be really appreciated. TIA

I'm surprised no-one has chimed in on this one - perhaps they're celebrating or commiserating...

I'n no expert, but I try to keep the main trimmed downwind. John Pearce put it best for me: "the sails don't know they're going downwind" - so trim them! Having said that, the spinni is the main engine, but the mainsail makes a difference too, especially if you're trying to lift the hull.

Yes, the main is acting as a backstay - but it doesn't have to be tight like the shouds - just don't let it go. And if you do, grab it quick!

The Tornados did the same under spi with the alu mast, but then it was risky. It was easy to break a mast if you overdid it. With the carbon mast the risk of breaking the stick is much lower so everybody do it.

The idea is to realease some sheet in the gusts when you become overpowered. The Alternative is to release the traveller somewhat or turn downwind. The traveller is a very coarse trim adjustment and turning downwind is even worse. With the mainsheet you have very fine control and it is fast. Letting the sheet out a bit in the gust and then sheeting in again to a nice trim is fast.

I always play the main down wind when sailing 2 up with the kite. Gusts come, shifts come and the flow over the mainsail changes. Easing the main also effects the shape of the kite as the top of the mast moves and so moves the head of the kite.

So, to an extent (depends on how strong your mast is) you can play the mainsail to keep the telltails flying. Let everything out and the mast might break so take some care.

If I had a spare hand I would play the mainsail down wind single handed on the F16. I will sometimes change it downwind if I am not on the wire or when I gybe.

great thanks for the advice guys. I'll try it at this weekend's race and see how it goes.

Please be careful with your mast. Let it out too much in a gust, and you might break it.

hey Rolf, on your f16, are u using an ahpc section? what is too much? sorry i know it sounds like a funny question, i'm hoping to find the approximate limit without having to actually experience it, i f you know what i mean

Do you hold the sheet in your mouth?

Sorry ckuang, I dont have a number for you. On the T we set the mainsail so the telltales streamed and went from there. Often that was with the traveller out 10cm and some sheet. More than one armlength of sheet released from that setting was more than what we wanted to try. I have seen some of the alu wingmasts really bend forward with the sheet released completely but that is neither fast nor safe. I dont have any advice but watching the mastbend and dont do anything scary.

I dont have a F16 yet. I have sailed tornados until last fall, then we began building some F16s. We hoped to launch this summer, but alas. Now we aim for next summer. We have a building blog here: http://woodastic.blogspot.com/
I have been hanging around the F16 guys for a very long time, but have not taken the jump until now. Our masts will be Tornado sections cut down to size.

I would say, unless your mast builder says otherwise, an "armfull" is the most you should let go unless you can afford some desctructive testing. I would define an armfull the distance holding the sheet whith your fist touching your chest to fully extended, so maybe 2 feet or so.

Rolf, you should come down to Singapore to sail the F16 championships we have here in January/February. It would be a nice break to the long winters no? But yes, have been to your blog quite a few times.

Thanks for the advice guys. I'll give it a go this weekend sans the sheet in mouth thing.

I can run you through it on the beach if you want. But will be a bit hard I think to swap boats on the water though!!!

Travelling to Singapore during our winter would be great, but I could not even afford to go to Mumbles..

Help me out here

You ease the main to depower the spinnaker?

Shouldn't you sheet in to centre the mainsail and reduce the area affected by the wind because easing the sheet presents more surface area?

If you are still overpowered don't you then ease the spinnaker sheet?

The way I see it, the main contributes to a lot of the heeling forces when sailing downwind with spi. Easing the main will remove drag and heeling forces. You depower the boat, not just the spi. The main also create some drive, so there is a balance.
If you sheet in and oversheet by doing so, you are creating even more drag which only helps in slowing you down and pulling you over.
Sheeting out on the spi is of course first priority. I think you need to put the whole thread into context to make sense of it.

Just my take on the topic.

It is complicated........

First consider letting out the kite and nothing else...

It flogs and you loose power but the whole rig becomes unstable. If you decelerate, the kite then starts to power up again (maybe).....

What happens if you oversheet the kite?

You loose power and so you may reduce heeling moment and thus prevent a capsise or pitchpole, but you then have tight sails and may be in trouble as the rig loads up as you might simple blow over sideways as the apparent wind moves aft as you slow down.

IMO, you need a mixture of the two.



Now, consider what happens when you free some mainsheet and do not change the kite. Letting some mainsail out you reduce heeling moment and drive (remember if you decelerate you may bring the sail back into the sweet spot and then power up again). BUT also what is happening at the top of the mast?.... Less sheet load means the mast tip moves forward (and maybe away from you). BUT the distance between the head and the tack of the kite has reduced and so the shape of the who kite has changed. This MAY also flatten the entry of the kite (most kites flatten as you ease tension in the luff).

Time on the water is key, but initially I would suggest dumping an arm full the kite until you get batter and can then combine oversheeting the kite with dumping small amounts of mainsail and then re-shet kite and mainsail and you will then also learn when you cannot over sheet the kite. It takes time to work it out.

For once we disagree Simon. I think an armful to be the max, but very soon you will want to begin easing just 10-20cm before sheeting in again. It is all about feel for the boat and the conditions. Anyway, key is to not accidentally adjust rudder angle while sheeting the main.

I dont know how much the mast moves while sheeting the main going downwind and how that changes the spi shape. Never been in a position to study that.

Rolf, Are you talking about the main as in "an arm full"; if so I agree, I'd never suggest dumping the main in the gusts unless you want to buy a new mast...

I agree that sailing down wind and playing the mainsheet, you MUST stear carefully at the same time. I think the T medal race action from the Games where it shows Bundy putting the mainsheet in his mouth so he can still steer with one hand while playing the mainsail is a classic demonstration of sailing down wind 2 up.

[quote I think the T medal race action from the Games where it shows Bundy putting the mainsheet in his mouth so he can still steer with one hand while playing the mainsail is a classic demonstration of sailing down wind 2 up. [/quote]

'cept he was on the tramp...thus only 1 up ;-)

From a post today over on the TornadoCat Yahoo forum from Oskar Johansson (Team CAN helmsman):

And finally some online coverage of the Tornado medal race: http://www.youtube.com/watch?v=6xiQUFRM8QM

I don't speak that language, but it was still better commentary than Gary provided. <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />

Comments are very good and insightful. I think it might be one of the danes who tried to qualify in the Tornado who comments?

'cept he was on the tramp...thus only 1 up ;-)

From a post today over on the TornadoCat Yahoo forum from Oskar Johansson (Team CAN helmsman):

[/quote]

Mike, you've lost me with the part I highlighted bold above.

Does anyone know why GER put it in the p155 as Ben so eloquently put it?

Also, does anyone know if all the on-board footage was captured and will it be released?

Mike, you've lost me with the part I highlighted bold above. [/quote]

I bolded the pertinent words of your post...a classic demonstration of downwind sailing 2 up...but Bundy was sailing 1- up <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />

According to what I heard, they hit something in the water and had damage to their rudder system. Game over..
Rumours say a big jellyfish. It is all rumours for now though.

I can not imagine that all the footage will be released. The producing company paid money for their rights, and they will probably not see enough money in it to cover the cost. I dearly hope I'll be surprised!

Oskar stated GER hit something, popped leeward rudder (damaged it) and went over.As for the on-board footage, don't hold your breath for an official DVD distribution from NBC...there's no Michael Phelps content afterall.

The best we'll have it what's on-line now.

Maybe they hit Michael Phelps?

I bolded the pertinent words of your post...a classic demonstration of downwind sailing 2 up...but Bundy was sailing 1- up <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" /> [/quote]

No he was 2up; Gashby was playing the kite?

If I was sailing 2 up; I would be doing as he (Bundock) was; If I was one up, I would have the mainsail cleated and playing the kite.

If I summarize correct, most of you would prefer to ease the main (a little) and the kite and would not steer down? So increase speed and keep the same heading?

Gill

Yes, if possible, sometimes you have to use the helm anyway though. Might be becouse of waves/chop or an extra strong gust.

Both if possible.

When I was sailing my Hurricane 5.9 with the kite up we would try and bear off, easy the mainsail and also (maybe) ease the kite a tiny amount.

Same comments as I made on the F16 forum really, what happens when you bear off, the apparent wind moves forward; but if you have a hull in the air, you need to either bear off, ease the mainsail or a bit of both. I'd go for a bit of both if I could, I'd then re-trim the mainsail while the crew continues to drive the kite.