I figure that is the case... and why should I care what the travel is if it does its job. I can have it full or flat using the DH. I ordered a new Glaser main ( last week so I can compare in another 4 weeks or so.
BTW, I went with Glaser because people recommended it and although I am sure Ashby and Landy make great sails, I decided to stay more "local" in case there is an issue. Also ordered new spin from Glaser.

Max downhaul? <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" /> The ronstan numbers are 2 cm each. Typically I start fully powered at about "3" and adjust as needed from there "5" being the usable max. or everything is happening within about 4 cm. range. Anything more is redundant... <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Does anyone have pictures of superwingmasts with a lot of DH on it?
I have pulled the DH hard on the beach and the upper forth (above the spreaders) ot the mast really bends a lot to the side .... When you tack it causes the mast to make a strange flip (before the tack he is bend to the right for exemple, so after it is bend to the left.) On the moment you tack all that power onto the mast switches from left to right, is this normal?

Regards,
Gill

We must all consider one thing here.

The superwing masts are rather flexible and as such the tuning and control of the mast top is always a play between the mainsheet, downhaul and the initial bend of the mast. If you just pull on the downhaul when the mast is straight on the beach. Then you will not be able to get very far. When you do it on the water where there is ample mainsheet tension producing on initial bend then you can get it very far.

The more the mast is bend initially, the easier it is to put more downhaul on.

It is not usefull nor wise to ONLY pull hard on the downhaul when the boat is on the beach head into wind and with a slack mainsheet. The only thing you are doing there is trying to damage your sail.

Therefor you should always adjust BOTH the downhaul and mainsheet together. This may not have to mean at exactly the same time but right next to one another nevertheless. Always start with the mainsheet when increasing the downhaul and start with the downhaul when decreasing its tension. Of course this is not necessary for small changes; we are talking big changes here, like trying to get to the max.

Gilo, on the water the mast will bang less from side to side as the mainsheet will be "on" and keeping the mast bend through the tack. Simply put not everything can be similated on the beach and this is one of those things.

Wouter

How much rotation did you have when doing this?
I would imagine if you where sailing with max downhaul the amount of rotation would be very little, and this might also influence the amount of "bending"that you mentioned.

Wouter,

are you sailing trough tacks with a tight leech? I think not.. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />
In other words, you will release rather a lot of sheet tension in tacks. Loads on the luff, especially in superlight conditions where the downhaul is really cranked on, will be rather large no matter what you do. I am of the opinion that the luff should be able to take downhaul loads even if you release the mainsheet. Yes, I know what Glenn has said earlier, and I dont consider it good practice going downwind with downhaul even if we used to do so on the old rig Tornado in strong winds...

I had an "eye opening experience" when a former olympic Tornado sailor was testing how flat he could make our new mainsail. Mainsails are tough sails taking very high loads!

You'll be suprised of how much tension is still on the leech even when the mainsheet has been sheeted out. Remember you are sheeting out to get twist in the sail to help accelleration after tacking, not to lower the leech tension to full slack.




If have been more then once surprised about how some "money's" have been able to break stuff through shear stupidity. One reason why I always tell all newbies to take care and think through what they are doing.

My personally ? Yeah there have been occasions were I could play the bohemian raphody on my mainsail control lines.

Wouter

I wouldn't call a former olympian with a bad back a monkey, he knew what he was doing and the mainsail took it nicely. No problem.
It would be interesting to hear Glenn's take on the same issue today as there have been quite some time since he said to always let off the downhaul when the sheet was released. Have other sailmakers expressed the same concern about the sails ability to take the loads from a full downhaul and no sheet?

When tacking in "normal" conditions I let out about 60cm on a 1:9 purchase system (I guesstimate, have never measured this). That should translate to a vertical movement of the boom for about 6cm? I dont know how much straighter the mast will go with a 6cm movement, but I think the bending forces you let out of the mainsheet system will have to go somewhere besides the leech. In the super light stuff we crank on the downhaul a lot to flatten the sail and get whatever airflow there might be to stream over the mainsail. At the same time we dont sheet much before we have accelerated. This should imply that the luff takes most of the loads bending the mast as we know that it's mast bend that flattens modern sails, not cloth stretch. Q.e.d. the luff is tougher than we think. Then there is the age old difference between shaving and cutting of your head.. <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />
PS: We dont sheet out just to let the air accelerate faster over the sail after the tack, but also to shorten the time spent before getting over on the new tack. With a tight leech the main acts like a weathervane working against your helm. Same when going into the tack, sheeting in to help your rudders heading up into the wind (you know this of course, but for the benefit of those who might not know..).

Guys:

I have a computip on Hobie 17. Don't know how that compares to your wingmast? But what I have noticed on both it and the aluminum mast on the Mystere 4.3, is that if I have to much downhaul in light air the battens sometimes will stay inverted on the main and I have to bang it in the draft to get them to go over. Maybe I should be easing a little downhaul as I go thru tack? Any suggestions?

Doug

I'm not going around chasing wraiths. I stick to what I said earlier. The downhaul and mainsheet are a combo and should be handled as such. On the water the effect that Gilo witnessed in his on the beach testing should be significant less because of the way the sail and leech remain tensioned while sailing.

Wouter

With a bit of luck, I'll have some time theis weekend to take some pictures of varying amounts of DH and manisheet tension.

Doug,

I have not noticed the same thing with alu masts, quite the opposite actually. Without downhaul we might have to pull the boom over to windward forcefully to make the battens pop over. Sometimes when going downwind in light conditions we have cranked on the downhaul to make the battens pop over instead of yanking on the boom.

Wouter, mainsheet and downhaul both shapes the main and works together of course. What I am pointing out is that you dont necessarily damage the main by pulling on the downhaul without mainsheet. Turning downwind in a blow on the other hand.. Chasing wraiths? Where did the scientific, argumentative, Wouter go <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />

Hello Gill,

Here are 2 pictures of an Ashby mainsail on a 2005 Blade. One with downhaul off and the other one downhaul (and mainsheet) full on.
This range looks pretty good to me.




Geert

Great photos from Geert. I also have an Ashby main (although smaller); one thing I've noticed in the photos and on my own sail is that you can really flatten the sail. Glenn told me this is so that once you're up to speed you can flatten further and further to absolutely minimize drag and raise your top speed up wind.

I need such a sail !

Wouter

Rolf:

May have to do with the fact I DON'T have a boom. Mystere 4.3 is a boomless rig.

DOug

Hi Guys,

Thank you for your answers!

@ Wouter:
When I tested the DH tension I had the mainsheet on and the boat wasn't pointed in the wind. I can understand that you can verify anything otherwis.
This weekend I go sailing the entire weekend, I'll check the mast carefully.

Geert thanks for the pictures, As with my mast, the tension doesn't bend the mast entirely backwards, but also sidewards.

Have fun this weekend everyone!
And see you at Zandvoort!!

Gilo

Okay,

Well good luck !

And remember each sail is different, you being one of the first Landenberger sails for the alu F16 mast. So you just have to look at how you sail shapes up will sailing and adjust it with small steps each time over a couple of weeks (multiple sailing trips).

One thing i found helpful (but I still need to do alot of tuning !) is to have streams fitted to the leech at :

-1- 0.5 mtr below the top
-2- halve way on the leech
-3- halveway between -1- and -2-
-4- Halveway between foot and -2-

With these you can fine-tune the prebend and diamond wire tension.

You should be able to get all streamers to flow and flick behind the sail at about the same time. Then the whole leech is trimmed well. On my own sail I still have trouble getting the top and middle to stream at the same time.

Prebend (rake + diamond wire tension) is a starting point from where you use the downhaul and mainsheet to further tune you mainsail. It is not unreasonable to expect different prebend settings for different conditions. At first just try to find a good average. When you really start racing then find different settings for light winds, strong winds, medium winds and solo sailing. Often the first two can more or less be combined into one setting.

Good luck !

I still have to take out a week of stuff to get my rig right. And I don't know when I'll do that before the World Cup. I may just not have a chance.

Wouter

Sorry, totally fogot to do this.

Looking at the results of the ECPR did you forget it was a race aswell <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />