I am sailing with adjustable diamond tension on my Blade and the times i did sail it now i changes constantly the tension when it is needed special up wind. The problem is that you don't have enough hands to change it down wind. On my boat it is possible to change the diamond tension from trapeze so i am flexibel when i am going up wind. I found out that the alu mast is responding more dramatically on the diamond wire tension than the carbon mast i am using on my A class and the reason for this is , is that the alu mast is not that close in stifness in compare to the carbon mast A mast.
The exact set up on how to handle in sudden wind conditions i still have to find out for the alu mast. There is some sailing needed this winter.

Regards,
Hans

Paul and Wouter,
The F16 is just insanely fast off the wind.I only concern myself with the proper angles and not slamming into what appear to be stationary objects (non spin boats), when sailing downwind.

We're at an important juncture with the wing masted solo F16's in that the old Taipn 4.9 advice to foot and go for speed to "A" mark is no longer fast.The new generation F16 mains (atleast my Glaser),can sail higher than anything except the Acat and best VMG is definitly achieved by sailing high and just short of pinching.My problem is that in light stuff lots of downhall and light sheeting is slow in even small chop (just no power in thesail).Additionally, the fact that the mast rotation cannot be seamlessly rotated into the luff curve of the sail says to me something is wrong with the cut of the sail and wingmast synergy.

If I could set the wingmast and sail luff curve properly, rotate for a bit more power, keep downhall moderate and have the power to plow through chop that'd be very fast.Slackening the diamonds with the innovation pictured would give me more draft in the middle of the sail and the proper rotation etc.

If this is wrong thinking,please chime in before my drill battery is charged!

PK

Hans,

You're onto something important here! When time permits (say within the next half hour or so), i'd love a pic. of your adjustable diamond tensioner.Have you thought about trying longer spreader arms as well ?

Paul Kilkenny

All,

Hans has been sailing many years with such a diamond wires tensioning system on his boats. He is one of the best guys to ask for his experiences in this field.

With respect to the drill, leave that tool in its box for at least a few more months. Well, at least that is my advice.

The comment made by Hans works both ways.



First intepretation is that alot can be gained by such a setup
The second intepretation is that just as much can be lost by using such a setup in the wrong way.

It is a double edged sword.




That is my opinion also. I'm increasingly "forgetting" to work the other adjustments as keeping the spi driving hard all the time turns out to be faster anyway.





We are never going to be able to point with an A-cat unless in extreme conditions. We've got that spinnaker setup in front of the boat and going up the mast. We'll always have more windage when going upwind. So my viewpoint is to get/stay as close as possible and then deploy the BIG GUN after A-mark.

But lets analyse we you got now and see where your rig is held up





Assuming that you have sufficient leech twist, I intepretate this to mean that either you have too much or too little draft in various places on your sail. It can even be the case that you have too little in one place and too much in another.

Can you decribe how you rig looks in these conditions. Does your draft distribution look uniform when going from bottom to top. Does you leech sudden bend to leeward at any place on the leech. To what percentage would you estimate the various drafts ?





What exactly are you saying here ?





How much rotation are you using in the really light stuff ? More or less then when sailing in say 8-12 knots ?

Why do you want to keep the downhaul moderate. What happens that you don't like if you pull more downhaul then this ?


Power in chop comes from increasing draft in the middle of the sail, pretty much were the prebend act is strongest. You can try to reduce this by reducing diamond wires a little and see how that goes. In effect the system in the picture will do nothing else; it only allows you to adjust it while sailing instead of on the beach.

If these test don't improve things then getting such system on your mast won't help either.


Pretty much what you are looking for is to set the top of your sail right by setting rotation and a combo of significant downhaul and little mainsheet tension. The very bottom of the sail is then set by the outhaul and the middle is set by having the right prebend set.

Apart from this you don't have any other controls that are easy to fine-tune, but when needed you can start including spreader rake and spreader arm length and when push comes to shoove different diamond wires can be fitted or even the hound fitting can be moved. But the last modifications are actually quite complex to get right.


When I look at this picture of your sail I have a nagging feeling that you sail is extremely flat.



Assuming your boom is on the centre line of your boat then your mast is almost fully DE-rotated and therefor there will never be more draft in the top of the sail then this. That is when assuming your mainsheet is not on tight here. Rotating your mast now to get more profile and more power will actually only depower your rig more. This happens as the top will present it more flexible side to the downhaul and sheet load and bend more towards the rear taking out more and more luff curve making the sail flatter. That is my initial assesment


P.s. are you still using the Taipan mast settings or the ones Jay gave you ?


Wouter

Paul,

I would debate the benfit of adjustable tensioners during a race, mainly becuase it is just 1 more thing to worry about and distract you from actualy sailing. Some of the A cat guys swear by them but mainly as a quick rigging adjustment if the wind speed changes drastically between races when you are out all day. It may be a cool device to use to test sails though to find that median sweet spot.

The new big head sails need stiff masts. The A guys are really finding that out, gone are the days of tuned masts for sailors weight. As Hans pointed out the Aluminum mast is not nearly as stiff as the new carbon ones. Everything you can do to stiffen it up seems to be quicker. The Taipan class rules were 700mm spread. We started here and I am now using arms that are about 10.5cm longer than the Taipan length spreader arms and it seems to really help. The top of the mast is where you then have to really concentrate to keep the rotation in tune with what shape you are trying to keep in your sail. Just a slight bit too much rotation and the top of your sail will go board flat AND not twist off. We only over downhaul in the very light stuff (when the crew has to go leeward)for a flat sail. As soon as we can almost both sit on the same side I am filling up the pocket with more rotation, less down haul and a slightly looser sheet. Keep that smooth transition of the mast and sail luff you mentioned at all times up wind.

This suggests to me that you are using 3 mm 1x19 wire for your diamond wires, is that true ?





I think we can do something about this without having to get a new mast section. It won't be major but it can well be a sizeably step in the right direction.

I'm trying to develop/validate my model and I can very well use more experiences like this.

Wouter

I did some quick measurements on the Glaser sail in the photo. Photo analysis is never 100%, but the the best of my efforts gave:

Twist: 4deg
Camber top: 10.9%, position: 33.5%
Camber middle: 12%, position: 35.6%
Camber bottom: 11.6%, position: 40.5%

Measurements was done on the sail itself, disregarding the mast. Add about 2% draft to include the mast (rule of thumb on regular teardrop shaped masts, dont know about the SuperWing section). This results in a final draft of about 12-14%, not a very flat sail in my opinion. To compare, my own Tornado main cut for a heavy team was designed with app. 10%draft (+2% for the mast = 12%)


Was this sail designed primarily for uni-rig sailing, or sloop?




Adjusting diamond wire tension is something we do between races if the conditions change dramatically. Using a tension adjuster like in the photo on the A can be worthwhile as they need the extra power downwind. Spi boats dont want an extra full mainsail going downwind, we want to keep the slot open.

That is what my model says as well.

The A-cats can accept larger induced drag forces when they are beating downwind as their apparent wind angle (over the mainsail) is alot more perpendicular to the direction of the boat. Here the drag is not trying to slow the boat down anymore but rather trying to push it to the side. A direction that is easily resisted by the daggerboards against a very small in-line drag penalty.

F16's however with the spi tend to have the apparent wind over their mainsail rotated much more along the centreline of the boat so any increase in induced drag is immediately transformed in in-line drag and will try to slow the boat down. In most case it will therefor be better to keep the mainsail breathing freely with a relatively low draft to cut down on induced drag. Exactly the same as when going upwind.

Up till now everything makes sense.

Wouter

Gosh,

I've written down five questions posed by you guy's in the previous few posts that are central to my problem (will loosening the diamonds in light wind make my sail faster/ more powerful).Fact is,I need to collect some more data and be a bit more thoughtful about sail shape.I promise to do so and report back.

I am quite sure that the Glaser main has made me much faster
to the windward mark.Infact, if I sail even a mediocre race(sadly demands of a new job have me aspiring to mediocrity of late) i'm in with a chance to win.I've attached finish times for one of the two mediocre races I was able to muster at the Alter Cup Qualifier (attached).Top two H16's are former national champions,the Acats ar really well sailed and will be top twenty or better at Islameralda, the Tiger started well was sailed agressively and nailed every lift first all weekend.A snapshot of the F16s speed by comparison...

PK

Cool thing: I suspect we're not close to tapping the F16's potential for outright boat speed!

I see that you made a photo finish with the leading A-cat for 2nd and 3rd place, Paul.

2nd A-cat elapsed = 26 min 40 sec
3rd F16 (paul) elapsed = 26 min 41 sec

Very Nice

Guys, we are getting somewhere now.

WOuter

Nice racin' Paul. Of course, there's that growing sentiment about our rating.

Hiya Doc,

I attached one of my two half decent races. Saturdays tally was a 13th (first until I reached off toward the wing mark on the last lap*),a second, a 14th (pulled rotator line through my mast and had to sail overotated in 17knts.),and a third. On Sunday Zinnia slapped my cheek and said, " be consitent!" so I sailed consistently worse than I have in a very long time...
Boys, do whatever you want to the PN - i'm sailing with Paul Alani for now on...

Paul

* PRO set a windward - leeward with no B mark