I'm posting this thread on be half of my friend.

He has a Nacra 5.5 sl 1996 make and it's time to buy new sails.

He is playing with the idea of changing the sail plan

1. Main sail with square top and more sail area.
2. Smaller Jib that will enable to install a self tacking system. (losing the mess on the tramp)
3. losing the bridal foil
4. Adding a spi

He dose not race at all. Class legal is not an issue.
He is attached to his boat and will not sell or change it.

Has any body done something like that before?

How will the modifications to the main and Jib effect the sailing experience on that boat?

Will the mast take the modifications?

Is this a good idea?

Thanks,

I think the Nacra 5.5 is an excellent platform to upgrade. It was always a sweet boat.

If I had one and wanted to do the same, I would do the following:

1. Contact Randy Smyth at The Smyth Team or Jay Glaser at Glaser Sails to design a new fathead main and smaller jib. The geometry of the 5.5 fits well with current F-18 sail plans. The spinnaker design and shape could also follow F-18 trends.
2. The mast should work fine with those modifications.
3. The boat will be faster with the new mainsail and easier to sail in high wind.
4. I would consider going to a boomed rig with a floating clew similar to what has been done on F-18HT, A-Class, and some Tornados. You'll simply get a better looking mainsail with a boomed rig.

Hope this helps.

Bob Hodges
A-Class USA 230

I would leave the bridle foil. It allows you to put the jib lower on the boat and reduces the stress on the hulls. Also its a good place to tie the spin pole to.

Yes definitely get a boom with the new sail.

Does anybody know how to contact Mr Smyth?. I have not been able to get info on his loft. Jay provided a quote for my P19 following the setup described and was very helpful and informative.

The jib on Nacra 5.5 & 6 is huge, so may be this is the reason you want to reduce stress on the hulls. But ones you cut the jib it is not necessary???

What is the advantage of putting the jib lower?

Found this on the web, I guess he done it

"Flippin Fearless" looks like an older Nacra 5.2. The Nacra 5.2 had the center bar that ran between the center of the front and rear cross beams, had no brial foil, had a boom (vice boomless 5.5) and had straight spreaders on the mast instead of spreaders that angled towards the rear. But I am not personally familiar with "Flippin Fearless"

I agree with the mods on the original post except for removing the bridal foil. It is supposed to reduce the stress on the hulls. The other advantage was to have a lower jib attachment point so you could have more jib sail area. The 5.5 does have an overlaping jib (goes past mast) but it not nearly as large as the Nacra 6.0's jib. If he would be using the spi extensively, the jib size could be reduced to allow for the self tacking jib without affecting much. I did not add self tacker, but hooked the jib bocks to the tramp to get rid of the wire across the deck. The Spi poll can be put under the bridal foil without problem. I do not know how much spi load the mast will take. I only run my spi at light to moderate breeze (up to 12 mph) because I am afaid to stress the mast more as it was not designed for the spi.

My Nacra 5.5 modifications are at nacramania.com

Patrick,

What type of boat is that in your personal thumbnail picture to the left ?

It doesn't look like a nacra 5.5.

If I had to guess I would say that that is Hollis Caffee old boat.

With respect to Flipping Fearless, I think that is Nacra 5.2 as well. I think it is Jake Kohl old boat so he can shine light on this mystery for us.

Wouter

Patrick,

I'm already familiar with your web site, I think it is great and have a lot of interesting and useful information.



In fact the only reason I think the bridle foil should go is because you mentioned on your web site that the bridle foil is getting in the way of the spi line while jibing





The question is:

Is the bridle foil there because the designer wanted a big Jib?

If yes,

Ones I reduce the sail area of the jib, the bridle foil is not necessary???





maybe this link can help?
http://www.floridamultihullsailor.com/hagar_web2005/hagar2005_p1.htm

Wouter,




Very observant. You caught me. Yes that is Hollis Caffee old boat. I have bought it and am bringing it up to the Chesapeake bay area. But thats a topic for another place.

Erez,


Unfortunately I can not answer the structural need for the bridal foil. The 5.5 began life as a Uni so possibly was not engineered to take the stress pulling the bows together, and the bridal foil was the answer. Or maybe it was just to put the jib lower to get more jib sail area. The safest route would be to keep the foil, but there have been many Nacra Uni's that have had spinnakers put on which probably put a lot more force on the front hulls than the jib, and I have never heard of a failure, so it might be safe. The Nacra's are built fairly tough. My guess is the mast would fail before a hull if the spinnaker was overstressed.

See my private message in the www.catsailor.com mail box

Wouter

"Flippin Fearless" was my 83 (maybe it was an 82) Nacra 5.2. The sails, a square top pentex mainsail and a dacron jib, were made by Calvert Sails in Florida - they did a really nice job. Frank added the spinnaker (I think it came from an F17...not sure) and the snuffer. Before doing so, he removed the decks and rebuild some of the substructure in the hulls - they were getting a little soft.

As far as the bridle foil goes, the current ones (N5.8, N6.0NA) do very little to reduce the stress on the hulls. The short bridle wires that go from the hull to the foil are still angled inward almost as much as they would be if they were part of a more traditional bridle/forestay arrangement. This angle is what dictates the inward stress on the hulls. The main focus of the foil is to allow a larger jib that runs lower where you can extract more power from it.

I would go to a top sailmaker. I would probably use one of the f18 sail designs and make the front of the boat fit. The big advantage is, existing F18 sail designs have been tested. I have had 5 custom sail rigs built. 1 out of the 5 was SURPRISE, you didn't think of that

Based on 6.0 experience, getting rid of the overlapping jib will help upwind performance, a lot. Adding the sq top main will move the center of force aft. It will probably load up the rudders and you will have to experiment with mast rake


I would keep the foil. The 5.5 bows are pretty flexible.

i had a n5.5 uni about 10 years ago and loved it. wanting a bit more juice downwind, i built a bow foil, added a very lightly built spin pole and installed a reacher (on a roller-furler w/ 1:2 reverse purchase furling line) and went to town.

it was really quick downwind in light stuff (faster than wind speed by a good bit and didn't seem to suffer too much upwind. in windy stuff, i knew (all too well) that i could pitch it quickly, so i put the hiking stick under my butt and steered w/ the two sheets. seemed to work well.

the bow foil was important because the angles of the forestays changed so radically with these mods. the stock 5.5 uni forestays joined about a foot below the hounds, so a much lower join would radically change the loading.

i mentioned that the spin pole was very lightly built. i did this as a visual stress cue for over-enthusiastic skippers (me). when it started to look like a pretzel, it was time to back off.

i think the subsequent owner upgraded the pole and soon had a two piece mast. good times.

Hi,
I have purchased and owned a 5.5 uni and two 5.5SL's - great boats!

My advice, for what it's worth:

If he's not racing, he can do what I did when I was not racing - eliminate all the criss-crossing wires on the trampoline (the shin-scrapers) and mount a block with a cam-cleat directly to the forward-aft traveler track(s). (like a Nacra 5.8) I would leave everyhting else as-is. (And of course, add a jib furler, as both my 5.5sL's had)). A smaller-higher jib will not make the boat any more stable or easier to sail, and the pin-head main is fine too. Why spend so much money if it's not class-legal and dosen't make pleasure-sailing more pleasurable? Take that money and buy a cover or cat-trax or aluminum trailer or self-cleating Oxen blocks - or a lighter mast maybe...

Steven Bellavia
Hobie FX-1
Sail #211