Hi everyone, I recently bought a 6.2m 2008ish neil pryde sabre to replace my nearly stuffed 6m 1996 V6. The V6 was obviously a pretty grunty sail compared to the no cam saber, however every sail I would forget to put on that little strap on the Saber that goes around the mast at the bottom of the sail. However today I actually remembered to put it on, and as a kinda apprentice sailmaker at a boat building place I wondered what the point of this strap was. Upon pulling it on I discovered it adds depth to the bottom of the sail, kinda like letting the outhaul off, but in reverse. So I was wondering what's the normal range people use on this strap, because today it was pretty light when I went out so I had it cranked and the sail was pulling like a train down low, compared to the normal light, gutless feeling it had before, and my arms were getting fairly sore, even fully committed to the harness and straps (don't normally get sore). I'm pretty sure the harness lines are right too because I can sail around 1 handed for ages. So did I just overdo it (there were crinkles in the 1 foot surrounding the strap on the sail, but the overall shape was nice), or I just need to toughen up? And do you guys and girls adjust it like you do the downhaul for each day, or kinda just set it once and forget?
Thanks, Sailingkid
Heavy sail feeling is often caused by not enough downhaul. The leading edge of the sail should be about the same angle to the wind along it's length. This means that the flatter top section needs to twist. If the bottom id bagged out, the top flat, and the leach tight, there will be drag caused by either the bottom presenting too blunt an entry or the top too fine an entry.
This results in that "heavy" feeling.
the way a sail works it's not only the leach that twists but also the foot of the sail.
putting the tack strap around the bottom of the extension and tensioning will tighten up the foot of the sail mainly and tighten up the leach to a smaller degree also. this is not the case on all sails.
so in light winds. crank it on hard.
in heavy winds crank it on not so hard.
then set you sails downhaul to suit the wind.
Have a look at www.severneracing.com/rigging_video.php
According to Ben, due to the position of the block the foot tension sits slightly higher than the foot. Tension is brought down lower by the tack strap.
edit - wrong vid
i must have missed something paddymac. i watched that wentire video and no where did ben s actually state what the tack strap is for.
Thanks lungs, that's the one. Ben and Dave look sooo similar you can easily see how I got confused 
7:15
I have a couple of Saber sails and they are my favourite no cam sail.
I set the DH to max recommended and use a tight tack strap.
Then use the outhaul to regulate power / back hand pressure. I generaly sail neutral OH but the sail has plenty of power and twists of nicely. When thwe wind comes up just crank on some OH.
The Saber is quite a locked in and relatrively light sail to use.
7:15
Bit off topic but the last sail I had with my KA 6.6m Koncept I really downhauled it.Much more than usual so the top 3 panels were flapping and making a crinkle sound.Usually I have them loose but not that much. I also put a little out haul on but not as much as usual. I like to go upwind a lot and I wasn't sure how it would go with less outhaul.
Usually I find that sail hard to pull on once the wind gets up to 15kts odd. 
Wow what a difference! 1st time I've ever felt totally comfortable and blitzing upwind.What a difference downhaul makes!
Best sail I've had for ages.The wind was ideal 15-17kts.
Last few downwind runs were scary with wind at 20kts and choppy with the big board & sail.I weigh 61kgs & had the 6.6m up and others at 75kgs were overpowered with a 6.3m so I was glad to get in in one piece!
^ Less downhaul, more outhaul for upwind. Overall flatter sail.
This is because the apparent wind at top of sail will now be at a very similar angle to the apparent wind at the bottom of the sails.
Opposite for downwind.
(basically flat for upwind, shape for downwind)
