I have a Nacra 5.5SL that never had a mast rotator installed. I want to install a mast overrotator. The 5.5 is a boomless boat.



I am looking for information on how high up the mast to install the rotator. Plus any other tips or tricks or best ideas on where to install the cam cleats, etc. I have a standard spinnaker, used occasionally, launched from a bag at front of tramp which might get in the way, if that makes a difference.

I had a 5.5u with the over-rotator. As I recall, it was mounted as low as possible without the bolt actually going thru the mast base casting. There was a padeye on the front centreline of the mast about 8" above the rotator with a loop of 1/8" poly line running to both corners of the rotator to keep it from swinging down and hitting the crossbeam. The cleats were rotating bullseye cleats mounted about 18" out from the mast base on the main beam, using extended bases which put the the eyes about 4-5" aft of the centreline of the main beam. If you have the standard traveler cleating to the centre of the rear beam, it should be the same cleat on the same base.

As for the chute: It has to go out the sides, under the jib sheets, right? It doesn't launch over the front beam but over the juncture between the front beam and the hull? It shouldn't be a problem; the rotator gear is limited to the centre 2-3 feet of the main beam, and a line about 5" behind that. I ran a continuous line that only had a little slack, so I didn't have to be tending it all the time. I also did a distance race with the chute, and believe me, it's really nice not to have to mess with a jib! Of course, I then had to go and buy a Prindle 19...



Anyway, good luck. I'd shoot you a picture, but I don't have any, and the boat is sold now and a good 4 hours drive away

On my N5.8 I have a similar setup to what Andrew described. It work good. If I recall, the Murray's catalog has a picture of the setup.



I have seen some who have a bull's eye instead of the cam cleat 15" on the crossbar, and the rotator line was led a little farther out on the crossbar, such that it could be adjusted while out on the wire. I have never sailed with that setup, so I cannot say how well it works.



David Rogers

Nacra 5.8 w/spin

Here's a photo that shows the cleat I use for the mast rotator, located behind the front beam. I run the line out through a fairlead at the end of the beam so that the mast can be rotated from the wire.

I think the reason that I never felt like it cost me time, either upwind or down, not being able to adjust mast over-rotation from the wire, was that if I was trapped, by definition I was NOT looking for more power, and just let the rotation take care of itself. If it was minimal trap conditions, I'd be in and out anyway, and would just crank on the rotation one of the times I was in, or while tacking. I never tried locking out rotation completely to depower; I bet I would if I still had the boat! Rotation settings were: Upwind-as needed for a smooth entry if I was looking for power - usually this meant the luff track pointing at the shroud or so. Downwind: Same thing; usually meant cranked on hard, even to rotating by hand and then cleating the line to hold it there. Downwind with chute: Always cranked on hard to shift as much loading on the mast to the major axis.



hope this helps

Andrew,



To be honest, my crew (wife) has never used the rotator while on the wire. The fairlead at the end of the beam does, however, keep the rotator line tidy and out of way of other controls (of which the N6.0 has perhaps too many of).

I though my N5.8 had a lot of spaghetti on the tramp, but looking at that pic I realize I could be worse. I guess with the spinnaker bag and rigging, it is worse.



David Rogers

Nacra 5.8 w/spin

Why would you need to add an over-rotator if you are using a spi?

The main stays in an almost upwind configuration when flying an asym. spi.

Many Inter 20 masts have been broken when the mast rotates even a little too far with a spi.

I don't use the over-rotator while flying the spin. Reasons to have the Over-rotator with spin:



a) I've not always had the spin

b) For when I am not using the spin (taking friend out for rides, on windy days when I am not comfortable flying the spin

I just wanted to be sure that anyone reading this thread would not think of adding and using an over-rotator with a spi.

You might want to consider a shock cord type of setup like we use on the Hobie 17 & 20.

They both have the arm located at the bottom of the mast.

The same setup would allow you to have a mast rotation limiter on a boomless boat also.

Go to "http://www.nahca.org/news/tiger_2003_2.pdf" page 5, for pictures of the limiter setup on a Hobie Tiger. You would simply add a loop of line and a shock cord lead forward, to add postive rotation.

Sam,



I agree totally with Andrew's last sentence of his post.



On the original forum, (even before this one), overotating the mast with the while flying the chute was discussed, and by many, including R. Smyth, via Paula Smyth, was concluded was a good idea. Even though the main is nearly centered due to apparent wind, and tight to provide backstay, overotating also puts the vector of load more along the masts stronger axis.



Now you're saying that it's not a good idea, especially since the main is basically going to weather. I don't agree. Depending on the conditions, mainly wind and angle of attack, I overotate my mast while flying my chute.



I also have the rotating hound for my chute, similar to many Tornado's, and the same effect of the 'bail whire' on the Inter masts, which also benefits the loads my masts experiences. My hound height is now about 50% from shroad hoand to the top.



I also drop the mainsheet block prtion of my line and run the traveler portion of my mainsheet line.(continuos line). This enables to power/depower the main, while keeping the backstay tension via the mainsheet on the mast head.



My 2 cents.



Todd Bouton

N6.0na +

#111

I don't think we have the same definition of "over-rotated"

To me that means that the mast is rotated AT LEAST 90 degrees to the boat. That is why those "over-rotator arms" Murrays catalog page 34, are shaped that way, because you cannot pull a mast beyond 90 with a normal arm.

Now you say that your main in "nearly centered" "and tight to provide backstay".

Is that with the mast rotated 90+?

Are you twisting the base of your mast in one direction with the rotator, while the main is twisting the top in the other?



Don't forget, he doesn't have the massive mast your 6.0 has, (what does?) his mast is the same as my 18 sq.

SAM: I have both on my 5.5SL, as you may remember. Both have their place on the boat just not to be used at the same time. The elastic system like you have on your Hobie 17 won't work on a Nacra rotator arm. Your 17 rotator arm faces aft, Nacra rotator faces forward. AND, the Nacra hardrware is a lot harder to rotate than your 17 mast. Elastic just won't do the job.

PS: The new boat SCREAMS, I know why all the 5.5's killed my 17 on the circuit last year, they probably weren't even working hard.

CARY

I rotated the (early light) mast on my Uni significantly past 90 degrees under chute. Yes, the main is trying to pull it back. But with relatively loose diamonds on a non-prebent mast (like most Nacras) the rotation combined with mainsheet tension will put 3 or 4" of bend in the mast, with the added bonus that the spinn hound is now that much farther back - you have "free" mast rake aloft. I flew the chute on the Uni in winds up to about 12-15, but doused rather than trapping. I was trying to save the tender (and irreplaceable, as you know) mast, which came thru with flying colors.



sail fast

Hi Cary,

In the factory configuration, the "V" shaped arm facing aft and cleated to the boom, is a rotatation limiter. When we attach other lines to it to force rotation, it also functions as an over-rotator.

The big bow arm facing forward is used as only as an over-rotator. I don't think any boats come with these from the factory.

On the 18sq, many of us would flip the "V" around forward and only use it as an over-rotator. Some would replace the "V" arm forward with the "bow" arm for better over-rotation.

The elastic design I use was copied from a Hobie 20.

It works very well on the Hobie 20, which has a larger, heavier and tighter mast than a 5.5.

I could flip the "V" bar forward and use a postive lock system like I have on the 18sq. but it is not worth it.

I'll show you at Lake Murray.

You're right about the Hobie setup, Sam,100%. I'm familiar with your 17 rotator. I copied the design for my 17, since I forgot how Mike Murphy had exactly rigged it when I first met you. However, The 5.5 over rotator faces forward, is pulled aft and lateral down to the crossbar and cleated. It takes more strength to keep the rotation arm pulled back to OVERrotate than most bungee is capable of. Glad you're gonna make the race. Looks like we're gonna have a BIG crowd(for us), expecting 40+ boats, and still getting interest and committments. Have a 5 boat G-CAT 5.0 class, and the Hobie 18 MAG fleet is gonna show up in force too. Good prizes, Live Band, and FREE BEER too. Gonna bring your 17 and take on the Murphy boys or bringing your 18sq and race me and the Supercats?

www.seacats.org

CARY