Positive Mast Rotator

Does anyone have a slick positive mast roation system that they'd like to share? How does it bypass all the jib and spin stuff....

Here is a good system I've seen on Infusions:

Place a micro turning block (surface mount) on the front cross beam either side of the mast so the line will have a good angle from the rotator arm to the turning block. Then run your positive rotator line from one side of the arm, through the micro blocks and back to the other side of the arm.

Install micro cleats with no fairlead/eyestrap a little outside these turning blocks on the front cross beam. This is what you will use to cleat of the line and hold positive rotation on the windward side of the boat. When gybing, uncleat it and then sheet/recleat on the new windward side.

You can also introduce a safety in case you forget to uncleat it (which could lead to mast damage on a wing mast): splice or bend some very skinny tweaking line to the either end of your positive rotator line and use this to tie to the rotator arm. This way if you forget to uncleat and there is a lot of force on the mast trying to rotate the correct way this skinny line will break at the knot on the rotator arm. I used a similar system on an A-Cat and it probably saved my mast on a few occasions.


------------------------------------------------
..*Cleat*..*block*.../.m..\...*block*..*cleat*..
.....................|.a..|.....................
.....................\.s../.....................
---------------------|\t-/|---------------------
.....................|....|.....................
.....................\..../.....................
......................\../......................
.......................\/rotator arm............


Chris.

That my friend is brillant! The tweaker line should be mandatory.

tshan:

I think if you need positive rotation on your mast then maybe some rethinking about your setup is in order. I have not seen a posirotation system on an F18.

Maybe sailing way to low if you need the mast out that far. Most of the time the sheet will be pretty tight and the traveler closer to center than not. The force of the main sheet will probably be enough to push the boom forward, pushing the mast to where your rotation line is loosened to.

If you sail in lots of light wind and have to sail down wind in some long channel then maybe a rotation system is in order.

Dan

A positive mast rotation system is needed in the light and sloppy stuff. I typically have a soft main which does not keep the rotation where I want it. The positive mast rotation system will keep your wing mast exactly where you want it.

I had a similar system described by Chris on my 2006 F18 - I used it in only one or two events, but it was essential at the time I needed it. I haven't yet put it on the new boat, but will certainly be doing so soon.

I used 16mm micros attached at the inner jib track post as my turning block instead of using fixed blocks as Chris describes above.

We are adding a positive rotator if for no other reason to keep the rig from moving while sailing in light winds upwind in swells. it makes it easier to trim the jib and stabilizes the shape of the main. We used the system on the T-cat in conditions when the rig was slopping around or would not rotate to the prefered trim position.

It is for the really light stuff when there is not enough pressure to hold the proper mast rotation or when there is some periodic chop by bass boats going by at 70 mph. Just to keep the wingmast from banging around.

I am going to try this set up first as it doesn't require a lot of permanent fixtures (no eye strap on the front of the mast needed). Additionally, I am going to make the "gold" line a bungy, so I "should" be able to rotate the mast without disengaging the rotation system (assuming I can get a strong enough bungy to work while stretching enough to manually tack/gybe the mast).

It may not work, but it seems to be the simplest system to try first.

Tom,

I don't think the bungy will be strong enough. You don't need the eye strap like you said. You also do not need the block just tie one end of the line to the cleat and go around the mast and put the other end through the cleat.

How far back should the cleat be placed?

Nacra used to supply this as standard but now don't bother on the infusion. me or my helm keeping our foot on it seems to work

On distance races that can get really old - especially after a few days. For a down and dirty positive rotator on the Tiger I have a line tied from a jib track post on the port side. This line loops around the rotator arm and has a small ball on the end that is passed through a loop tied in the line to hold the rotator arm pointed at the shroud (the normal negative rotation system provides the ying to this yang). When not in use this is tucked into the port front tramp pocket so it can't cause a snafu.

We only use this in light conditions to maintain correct rotation, or light/medium sloppy where the rotator arm is bouncing back and forth. It is very quick to hook up or disconnect.

Why just on the port side? 'cause our multi day distance races are on the east side of the US and head north so you spend a lot of time on starboard tack.

Going around the cans I do as you suggest - use my foot or the crews. Positive rotator systems do not aid boat speed when you forget to take them off before gybing. We had overtaken Accelerated Chaos on the way to Daytona this year and then short gybed back to the beach and wondered why they got ahead again. It took a few minutes for me to realise we had sailed the entire port gybe back to the beach with the positive rotator holding the mast the wrong way. In my defense I had lost the lenses to my goggles overboard and was blind as a bat.

Chris.

This is what I used on my Hobie 17. Don't know if it will work on the F-18, but it was real simple to use and was self tacking and self gybing.

Doug