light wind rigging quandary

[cgoudie1]

So, if I understand correctly, your modified sail 'pulls like hell" but you still
don't plane up (I think you attributed this to the chop and "nose diving").

I'm guessing that your mods were to allow you to plane up earlier. Your
modified sail sounds a lot like my old Gaastras circa 1988. Huge warp
near the mast, wind range of about 3 MPH, pulls like hell (I might call that
drag).

The fact that the rig pulls like hell, and is nose diving in chop means
something. Several possibilities, maybe your board is too flat, and
you should modify it for considerably more nose rocker. More likely though
is the unbalanced nature of the rig. with so much warp towards the mast,
I might try the mast all the way back in the mast track. This might pull the
new COE more over the fin, and unwet the board for less nose dives, maybe.
But that may reduce your early planning depending on where the flat in your
board is.

Still wishing you the best of luck in the outcome you desire.

-Craig

[swchandler]

ittiandro,

It's good that you're being reflective and critical in your experiment. Any structural change in the sail's foil shape after your modification will have its consequences.

I've owned some sails in years past that were very convertible in nature with different batten options, including a 3/4 length batten above the boom. However, it's important to point out that the sail was designed to handle the stresses, particularly in the front end shape along the luff. In essence, the foil shape has to be structurally tethered using the right materials so that it doesn't over distort or wear too quickly over time.

I'm curious, did you shape the battens by thinning out them towards the tips? That would potentially allow for the creation of a softer foil shape and transition at the batten ends. Also, how did you fashion stops in the body of the sail for the shorter battens, and where exactly are they placed?

Some photos would be great.

[isobars]

Leech lines were explained by the lofts decades ago as a means of compensating for long-term sail stretch. Is stretch still a problem this century? And does it matter in subplaning (i.e., slogging) mode, which covers everything from 1 mph winds up to planing regardless of the wind speed? After all, it's not the wind speed that delineates subplaning from planing; it's whether the hull is planing or not planing (i.e., displacement mode, aka slogging) at the moment.

[ittiandro]

[konajoe]

A rig that is over-sheeted (stalled) feels like it is pulling like crazy, but goes nowhere. This is a big problem for folks sailing in light winds, even into advanced levels. The idea of sheeting out a little, resulting in less 'pull' sensation, resulting in more speed is strange to get used to. If the rig is stalled, the board may do all kinds of crazy things.

[ittiandro]

[quote="cgoudie1"]So, if I understand correctly, your modified sail 'pulls like hell" but you still
don't plane up (I think you attributed this to the chop and "nose diving").

I'm guessing that your mods were to allow you to plane up earlier. Your
modified sail sounds a lot like my old Gaastras circa 1988. Huge warp
near the mast, wind range of about 3 MPH, pulls like hell (I might call that
drag).

Thanks for your input
No, actually I was not aiming as high as planing, but at something more down to earth ( or to water!) : simply MOVING ! It may sound strange that this problem should beset a sailor like me who, while far from perfection, has quite a few years of experience, after all..And even more strange is the fact that I never had this problem with the older longboards and the nice, small sails designed to power them.

I think that my “ regression”, if I can call it this way, from movement to..rest, is due to the constraints of modern equipment designed for planing, which requires lively winds( mostly unavailable in this area) and relatively larger sails than for longboarding. Also, flat-bottomed hulls don’t bite in the water as much as the older V-shaped ( displacement hulls) and therefore may cause loss of power by way or a lateral drifting vectorial component...
People can say what they want, but unless one is a featherweight, he/she will never be able to plane in 12 knts winds….I weigh 85 kgs and if I want to move, let alone plane, in this wind range, even the charts tell me that I have to start looking at a 9 or a 9.5 M2 sail. The largest sail I have is an 8.5. It gets me nowhere. This is why I decided to modify some of my existing “ planing” sails, undoing their planing bias, with the hope to inject more power in them……
The first one I did, as I reported elsewhere in this thread, is a 5.6 Sailworks Race and it vindicates my reasoning: it has come back to life after shortening the central battens to about a foot from the mast. I was able to sail on it in about 12 knts ! Never happened before ! For sure, I didn’t reach planing, but I hope I’ll be able to get to it by doing the same with the larger Ezzy 7.5 and maybe with the Severne Focus 8.5 . I have nothing to lose, because, as they are, these sails are of no use to me .
I believe that the swath of loose fabric along the luff created after shortening the battens is what gives the additional power to the sail, by creating a deeper shape in the front… Perhaps there will be other problems cropping up, but going from..rest to motion and getting more power and speed from and hitherto dead sail is already a big step .
As to your diagnosis of the reasons why I couldn’t plane, in spite of the strong pull, I agree with you : the mast was probably not enough back or the rig might be unbalanced after the mods, although I don’t quite understand in what sense it may be unbalanced..

Ittiandro

[isobars]

[joethewindsufa]

here is a clip of some gentlemen playing in light winds with 6.x sails
one of the boards IS a BIC 293 and the other a Mistral Malibu
at about 2:30 the fellow is practically planing
and so, it is do-able to go on such a board with such small sails in light winds and have fun
hope the sail experiments work out !!!

https://www.youtube.com/watch?v=5NUDFFrzbmQ

About 12 knots is my wind minimum and here is my clip with a Mistral Equipe and TR-6 8.4 in 20 to 30 kph winds, which i call 12+ knots
however, the difference between 20 and 30 is significant !!!

https://www.youtube.com/watch?v=bOPP5pa4TAc
and my technique sucks

[techno900]

ittiandro said:

[ittiandro]