Mast rotation 4 boomless cats necessary 4 racing?

For downwind, yes definitely.

on my supercat 19 i use a mast limiter.... and down wind i use it to rotate the mast more.....

Definitely a plus on boomless Nacras up and downwind.

How about w/ a spin? The traveller is not out very far on spin boats off the wind.

I have trouble conceptualizing (?) the issue of mast rotation downwind because people set it as if the wind were really coming from the side when, especially with the spin, it actually isn't by the time you have apparent wind. So, according to wind flow, it should just be a little out from where it is upwind but everyone seems to blow it completely and let it go almost 90 degrees. Who knows though, just thoughts...

Could someone post some photos of the system. I am interested in installing one on my N 5.8.

Nacra 14sq the rotation becomes needed downwind in the light. Once the wind is up enough to force it around you are better off concentrating on not making mistakes and keeping your head out of the boat.
Up wind the in-haul is what sets the mast rotation so do not give it a thought as far as the spanner is concerned. Get the in-haul and main tension right and you are sweet. Again, less mistakes and mucking about inboard is faster.

Actually, you MUST have it with a spin. Otherwise, you can't control the mast rotation and it could rotate to weird angles and cause breakage. On a boat with a boom, that can force positive rotation with sheet pressure, it's not necessary to lock in the mast rotation.

Thanks. Any preference which way to mount the rotator? facing aft or forward?

I had a 5.5 with a spin. Mast rotator worked fine, but you have to watch it and limit downward movement, as it could get caught on the spi pole.

An eyestrap about a foot above the mast rotator on the front of the mast with a rope or wire leading down to both corners of the rotator arm to hold the rotator up will solve that problem.

yep, but I used a bungee

I have rotation-inducing hardware on both my 5.7 and 5.5uni, generally considered mandatory for downwind control of sail shape on boomless rigs. I'll take a picture wednesday & post.
I mount the rotator facing forward. And you must have lines to keep jib sheets from tangling.
Cleat position for rotator should be where you can easily release just before a jibe. I have a continuous line, so I can cleat & uncleat from either side, using H240 swivel cleats and bullseye fairleads. You'll need a special mounting pad to mount the swivel cleat on the NACRA round beam.

I made my own contoured mounting pads by cutting the material out with a hole saw. Then I taped 60 grit to the beam, and rubbed the pad back and forth. In just a couple of minutes the base pad contour matched the beam's contour.

cool idea, thanks.

I recently took my swivel cleat & pads off to service the old swivel cleat, and noticed corrosion on the aluminum beam under the pad. Any ideas on how to avoid corrosion like this? I'm used to seeing corrosion where SS screws go into Aluminum, but this was a 2" diameter circle that will eventually eat through my beam!
What about cleaning it before mounting, then using silicone or something to seal it and keep salt water out?

A simple and cheap way to stop this problem..clean the effected area, apply a thin film of

Calsium Starite

a polimer based grease.(clear lithium will work too) These soap based greases resist water and will stay put forever ! clean around the area after re-assemble with MEK or 111 tricloro.

Find a DuBois Chemical or Johnson-Diversey rep in your area..he or she will be happy to give you a small sample (-1oz.)if that fails, I will mail you some myself..

Another significant advantage (almost as important as the increase in speed!) is the Mast rotation limiters purpose as a depowering tool. <img src=

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Pics wold be much appreciated!

Jim, attached pic is how I setup my 5.5 Uni. Front rotator, blocks and front crossbar mounting blocks.

I over-rotate downwind. Only use upwind when I need to induce a rotation angle.

Sail fast, Tom G

Thanks.

I will have to be creative attaching cleats as the tramp wraps over the front crossbar.

Jim:
YaGonna Sail the TWM? We'll help ya tune yer setup there.
CARY
ACAT 29

Hey Cary, where you been hiding? Did I hear you are racing an A cat now?? Fill me in on a PM. Thanks. Tim <img src=

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I hope we will be ready by then, but it will not be easy.

Jim.

Nothing difficult about this. Fit the cleats with rivnuts. That way they can be easily removed when necessary

And cut holes in the tramp?

yes, you'll have to make some kind of hole in tramp, if it wraps over front beam, and you want to mount to front beam.
Actually this could be very small hole/grommet, to attach a turning block at the location where previous photo shows a swivel cleat, and then mount the swivel cleat out near end of the beam, past where the tramp is. Least damage to tramp that way.