Judders
Active member
So I clearly need the forum to point out where it's going wrong!
Pretty pleased with my sail shape
- Thread starter Judders
- Start date
G
Guest
Guest
I'm not an expert, but I'd go for more twist in the main - ie. open up the leech. Also, it looks very flat to me - which is good in F6+, but I suspect has too little drive for lower wind speeds.
All IMHO, and prepared to be shot down by the racers
All IMHO, and prepared to be shot down by the racers
Judders
Active member
I see what your saying but this shot actually was taken after I had moved the car out but sheeted in quite hard, in attempt to lower the centre of effort. I think we picked up a tiny bit of pace as a result.
fireball
New member
Flat sail in light airs is good too - otherwise the wind just gives up .... /forums/images/graemlins/tongue.gif
Judders
Active member
The top tell-tale is not flowing; now okay, it's a momentary thing but I wonder if I could get better value out of the top of the sail?
G
Guest
Guest
I think the theory (at least one of them) is that the higher up the mast you go, the higher the wind speed. And increased wind speed means that the apparent wind angle is more on the beam the higher up the mast you go. So you need some twist to mirror the changing angle of attack of the wind the higher up you go. The fact that the top telltale seems to be curling off to leeward might be an indicator of that?
flaming
Well-known member
Are you hard on the wind when this pic was taken?
If so the boom looks a long way off the centre line.
If not then I would add more twist to keep the flow attached at the top of the sail. When you're not hard on the wind you want all leach teltales flying, it's only hard on the wind that the top one should just be stalling.
Depth looks set for reaching, a bit more outhall wouldn't hurt for windward work.
Halyard tension looks ok though.
If so the boom looks a long way off the centre line.
If not then I would add more twist to keep the flow attached at the top of the sail. When you're not hard on the wind you want all leach teltales flying, it's only hard on the wind that the top one should just be stalling.
Depth looks set for reaching, a bit more outhall wouldn't hurt for windward work.
Halyard tension looks ok though.
Lakesailor
New member
I used to get that crease at the forward end of the top batten. I found that increasing the pre-bend in the mast using the forward lower shrouds helped a little in that respect.
PeteCooper
Well-known member
The draft is too far forward. Maximum draft should be roughly 50% back from the mast on a main.
gardenshed
Member
It isn't possible to critique your sail in isolation from all the other factors (strength of breeze, sea state, are you footing off or pointing etc). That said, the sail looks quite good and the only change I'd suggest is to fit a tapered top batten or softer top batten. That may reduce/eliminate the crease at the inner end of the batten. All the other comments (position of draft, twist etc) can be trimmed and tweaked by playing with the traveller, mainsheet, vang, cunningham, halyard tension & outhaul.
looks like you have a very good starting point to tweak from
looks like you have a very good starting point to tweak from
Judders
Active member
It's a broad reach in a light breeze.
tome
New member
If it's a broad reach you are over-sheeted, agree also that the sail is too flat for light winds. The tell tales don't do much to help on a broad reach
doug748
Well-known member
All your battens look very flat. Do you have them in the right way round?, ie the thin end should be towards the mast
jimi
Well-known member
On a broad reach, you are over sheeted, outhaul nd kicker are too tight. Depending on wind strength it may even be good to lose some halyard tension. De sheet until luff starts breaking and then marginally sheet in. You want the top tell tail fluttering about 80% of the time and the max draught about 40ish % back.
However I've never sailed on the broads so I'm no expert!
However I've never sailed on the broads so I'm no expert!
PeteCooper
Well-known member
Well you need to ease the halyard a fraction to move the maximum draft back a little. I was told many years ago by a sailmaker that on a small(ish) sail like this a full length batten for the top batten improves sail shape at the head. This is a cheap and worthwhile modification as it prevents the sharp angle at the front of this batten that you can see in your 'photo. If you were to e-mail your 'photo to your sail maker, which appears to be Kemp, they would give you some guidance on correct trimming.
peterb26
New member
Just open the throttle a bit more /forums/images/graemlins/smile.gif
Twister_Ken
Well-known member
Head scratch.
If it's a broad reach then you are oversheeted, but why are the leech tell tails setting?
If it's a broad reach then you are oversheeted, but why are the leech tell tails setting?
flaming
Well-known member
[ QUOTE ]
Head scratch.
If it's a broad reach then you are oversheeted, but why are the leech tell tails setting?
[/ QUOTE ]
I was just thinking that, looks more like a beam reach to me.
Head scratch.
If it's a broad reach then you are oversheeted, but why are the leech tell tails setting?
[/ QUOTE ]
I was just thinking that, looks more like a beam reach to me.
savageseadog
Well-known member
Have you got the leech line on too hard?
Oldhand
New member
Top batten looks far too stiff and I am impressed you seem to have achieved appreciable leech tension in spite of the topping lift appearing tight... The only time a topping lift should have any tension at all is to generate twist when going to windward in extremely light winds IMHO.