I dont know about the Blade specifically but I guess its pretty much the same on most beachcats. Low - Medium wind: Daggerboard/Shroud Medium - High wind: Rear beam corner.
IMHO: Speed gain between close and spot-on is probably negligible compared to a good start and smooth tack/gybes.
Petey: Higher winds you want it centered. This equals less draft, more twist - less power.
Less winds you want it more towards the daggerboards, more draft less twist - more power.
In your case, I dont think you should have it any further aft than the daggerboards. Reason is you have plenty of body weight to hold the boat down. You want max power so ease the rotation almost all the way out.
The trick is to see a smooth entry point on the leeward side of the mainsail. You can see this by noticing the lee telltales make sure they are flowing straight back and up a bit. The windward tales would be close to stalled.
The trick with this (as with most boat settings) is you need an "index". Mark your tramp at the pointing towards the shroud location. This becomes your upwind default that you will return to for upwind work. Having a mark also allows you to say things like "1 inch behind the mark" instead of pull it on a bit. At the end of each race return the mast the the setting you have been using on the way to the beach and when you get in measure and record the setting in a note book along with wind observations and how you thought you went boat speed wise upwind. You'll very quickly learn where it needs to be.
If your ringer is worth half of what you're not paying him, he/she will automatically tune the rotation anyway, its part of their job.
Re: mast rotation, again.
[Re: ]
#144206 05/28/0805:11 AM05/28/0805:11 AM
As mentioned before, on a wing mast, reduce the rotation to assist with depowering.
As for optimum, fully powered up settings....
Maintaning attached flow around the leeward side of the sail is the most critical and hardest to achieve. You want a smooth flow from the leeward side of the mast to the leeward side of the sail. Attaching some tell tails a few inches back from the mast will assist you in seeing what is happening with the attached flow behind the mast. (see pic)
I totally ignore the telltales when setting mast rotation and just adjust my mast rotation to get my leech to stand-up/fall-off properly. Mast rotation has a huge effect on this. I'm more geared to get proper twist and getting the flow to detach properly from the leech. If I don't do this then my boat "hangs-up".
Mind you the cut of my sail at the top may not be what it is supposed to be. I'm sailing with a Redhead mainsail. I think you have one too Pete. On other F16's fitted with ullman or glaser sails I think you can look at other things as suggested by the others. On the Redhead sail you have to check first whether you twist and draft profile is correct or risk stalling the top early on.
Wouter
Wouter Hijink Formula 16 NED 243 (one-off; homebuild) The Netherlands
1, Attached flow around the back of the mast 2, get the leach to stand up ENOUGH.
Ballpark positions for a peardrop mast
1, Down wind, off; so max 2, Upwind in light I go for max rotation, except in drifers and then have a little less 3, Upwind once on the wire, point it at approx the the shroud 4, upwind in the big stuff point it at the outboard end of the back beam.
I totally ignore the telltales when setting mast rotation and just adjust my mast rotation to get my leech to stand-up/fall-off properly. Mast rotation has a huge effect on this. I'm more geared to get proper twist and getting the flow to detach properly from the leech. If I don't do this then my boat "hangs-up".
Mind you the cut of my sail at the top may not be what it is supposed to be. I'm sailing with a Redhead mainsail. I think you have one too Pete. On other F16's fitted with ullman or glaser sails I think you can look at other things as suggested by the others. On the Redhead sail you have to check first whether you twist and draft profile is correct or risk stalling the top early on.
Wouter
You may be right Wout. I've been setting the rotation as suggested. Sometimes it works, but often my performance to weather is way below everyone else.
Re: mast rotation, again.
[Re: Wouter]
#144212 05/29/0806:29 AM05/29/0806:29 AM
I totally ignore the telltales when setting mast rotation and just adjust my mast rotation to get my leech to stand-up/fall-off properly. Mast rotation has a huge effect on this. I'm more geared to get proper twist and getting the flow to detach properly from the leech. If I don't do this then my boat "hangs-up".
I tend to control the leach with the mainsheet tension and downhaul. Mast rotation I only use to induce twist when I am overpowered and have maxed out the downhaul.
Re: mast rotation, again.
[Re: Robi]
#144213 05/29/0806:33 AM05/29/0806:33 AM
The trick is to see a smooth entry point on the leeward side of the mainsail. You can see this by noticing the lee telltales make sure they are flowing straight back and up a bit. The windward tales would be close to stalled.
Sorry Robi, trying to steal your thunder by repeating what you already have.