March 10, 2016

MK II Sail - Downwind Feedback


By Roberto, Wavedancer, and Brett
Here's an update from Roberto who has been testing the new sail on Lake Garda:

The MK II in the foreground was slower.
My personal experience is still doubtful. I like the new sail upwind in 6-16 knots and downwind in the range 8-16.  But I found it awful downwind below 5-6. Downwind and in very light air experienced two problems:
  • The leech remains closed as shown in the picture.
  • There is too much draft forward in the sail, just close to the mast.
You can reduce this draft by pulling hard on the vang to bend the mast but this makes the first problem worse. My outhaul in the photo is too loose but pulling it only makes it worse. The sailor with the older sail was definitely faster.

On the same topic, here's a question from Wavedancer and a reply from Brett: 

I am still wondering about the fold (top to bottom) near the luff downwind in light air (~5 mph). Should I try to get rid of it by putting on a lot of vang, or just let it be? Wavedancer

Just make sure you have your Cunningham set-up to be VERY loose for downwind. Even if you have to go forwards and push the sail up the mast. Don't use vang to remove it otherwise you are over-vanged downwind and will suffer. Brett

3 comments:

  1. I can see the difference in the picture and the old sail certainly 'looks right'. But what would happen if Roberto slacked off the kicker some (maybe more than he is used to) and got the out-haul tension right?

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  2. Tom, I cannot be 100% sure but I think my kicker was already off ( see the bome how high it is). I also expect nothing very useful by tightening the out-haul to release the leech. Maybe it is necessary to use it more as Brett said

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  3. Hi Roberto,

    The picture is certainly interesting but I can't 'see' the kicker tension. Are you really saying that only the weight of the boom is tightening the leech? I am sure the experimenting will go on.

    My only experience with the new sail is competing against one in the Uganda Laser Open just over a week ago. My borrowed boat with a well used old sail managed to beat the new sail over 10 races, mainly in marginal planing breezes and the usual sharp chop of our bay on Lake Victoria. But there are many variables and it proves nothing about the sail.

    I do find the new sail interesting. I guess that many sailmakers could have designed a faster Laser sail but it is quite an achievement to realise one that is 'better' but not obviously 'faster'. My experience with new stuff is that it can take a time to learn its characteristics and make it perform well. (Examples are in Lasers are the Radial rig and XD controls). The more people are working on it, the quicker the understanding will spread. When that happens, I think the new sail will be seen as 'better'.

    Happy sailing

    Tom

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