Any experience you care to share?

My brother's Nacra 5.5sl mainsail (pinhead) disintegrated (it was old) and he's looking to replace it.

I'm familiar with the advantage of a squaretop over a pinhead mainsail, but I didn't know if you could use a squaretop main without a boom...

its easier to install a boom.

you might be able to use a 2nd hand F18 sail than.

take a look at the A cat and F16 class to get an idea how easy you can build a boom system.

we tried a contender maxx sailcloth boomless squaretop by one of the world leading sailmakers and it didn't work at all and was modified for boom later to get it work.

Yes, currently have one, built that way by Randy Smyth. Make sure clew area will support all the force. The down side to no boom is that it is difficult to depower. Since mainsheet also acts as outhaul (no boom), travleing down will be more difficult. It tends to only goes down a short way on traveler without easing the main sheet. When you ease the mainsheet, you have now twisted the top, but powered up the middle at the same time. This means you have to let off even more main sail. If you are flying any extra sails from the top of the mast, spinnaker, screecher whatever, the mast is depending on mainsheet tension for support. If you are not planning on flying extra sails like that, then I would not worry about the negatives.
Good Luck

nacra 6.0 is an example, two in our club. Very nice. Everything should be square-topped

It's not exactly answering your question, but there is a brand new never used Nacra 5.5 square topped main in stock at the dinghy store, and I know that the owner doesn't know what to do with it as nobody is sailing a 5.5 anymore around here. I don't recall the specific info about the sail, all I remember is that it doesn't fit on my 5.2 'cause I measured it a while back. But it looks like a boomless squaretop mainsail, and it is definitely for a Nacra.

It's in the UK, but hey, you may be able to ask a good price as it has been sitting here for a while... It's not listed on the site, but you should contact them: http://www.dinghystore.co.uk/

Waterbug, also exploring options for a square top on my 5.5 Uni. I now have 2 pinheads with differing performance characteristics both from the same sailmaker. Go figure.

My challenge is now finding a sailmaker with enough square top design and real-world refinement experience on the 5.5's. If I locate that person, they will already know how to address Nacra's traveler at the foot of the sail with the composition of my mast (carbon).

Let me know what you find.

Sail fast, Tom G

Square top on a 6.0! - madness. The stock sail was like working on a chain-gang anyhow!

6.0 + Squaretop = Yahoo!

Gang:


what I have learned from the Mystere 4.3 is the squaretop give a lot more area up top in light air. Also the top will bleed off to depower in a blow.

Love both of min.

Doug

Keith, love it, now that is one hot looking Nacra sail...is it from EP?

One of our 6.0 guys has the smoke colored version...mighty nasty!!

I am wondering how much more development went into a 6.0 ST?

Sail fast, Tom G

Back in the day of the Worrell 1000.
The Nacra 6.0's were using the pin head mains.

The Mystere 6.0's were using the first generation squaretop's ripped off from the Tornado sport developed by Booth et al and made by Santonge in montreal.

Hans Meijer's opinion at the time was... the square top was great in the light stuff.. But once you started depowering... the pin head was more efficient because there was less drag up high on the pin head mains.

So... in the point to point race of the worrell... as the breeze came up in the afternoon... the Nacra pin head's got faster and walked on the Mystere 6.0's...

Now... there are probably a 1000 other reasons... but interesting none the less.

That's actually a Smyth sail. We liked that sail in both the light and heavy stuff. One thing that was really nice about it was that was much lighter than the stock pin head head main - the boat felt much more controllable when the wind was up.

C'mon Keith, show me a picture of the sail working properly, like with a jib and sheeted in.
not sold yet

[Pinhead]Paul

Several thought or, question provoking perspectives.....

Are any of the new-technology boat designs (F18's,etc.) using pinheads or square tops from the get go?

Considering the Tornado, Tiger, F18's, about how often have their respective sail plan designs evolved after considering real-world experiences? And, have they evolved towards pin-heads or square-tops?

Leaves me wondering though, in getting back to one of the original questions; does anyone know of a sailmaker who has perfected a square-top sail design for a Nacra 5.5? Or, is it pretty much a chance deal?

Sail fast, Tom G

I think it's pretty clear that everything is advancing toward square tops. They keep getting squarer and squrarer - the sails approaching almost as wide at the top as at the bottom.

Actually, for that day the sail as shown was perfect. This was the start of Chesapeake-100 that started in nuclear conditions. We were taking hits from heavy hitting gusts here in the harbor, heading on a close reach. Later we blast-reached down the Bay under main only, double-trapped, averaging 20 knots. Lower on the Bay when the wind dropped out the jib came out. There was a lot of carnage when we cleared the Harbor and got into the West River. Lots of boats dropped out. A lot of the other pictures of this set up is in lighter air, I'll see what I can find...

By the way, out of this set up, we liked the main but always thought the oversized jib was a little difficult to make work.

I would think that as long as the luff measurement is pretty close to the pinhead 5.5 main, you could run any Nacra F18 squaretop on it. There should be a few used ones around for cheap. Then, all you would have to do is have a good sailmaker install the outhaul from your old boomless main to the new one, or just get a plate with several holes installed, and get a hook for the top of your mainsheet blocks.

For a constant sail area, square tops have a couple things going for them: they have more area aloft for better light-air performance. In a breeze and above, they benefit from their closer-to-eliptical shape and higher effective aspect ratio, both of which reduce drag.

The place I expect square tops to be clearly inferior are in survival conditions, where the wind is so strong that travelling down is not enough, and you must ease the mainsheet to depower. When things get that ugly, the pinhead would definitely help... but those are not typical race conditions.

In double-trapped-and-depowering conditions the square top has a higher effective aspect ratio, and the pinhead has lower center of effort. I would not expect a big difference in these conditions, but I'd expect the higher aspect (lower drag) square top sail to point higher, which can be a tactical advantage, and compensates somewhat for the reduced power.

Kaos points out that the 5.8 can be hard to depower. I'm not speaking from experience, but the 5.8 system (with clew track on the main) should work fine until the clew track car is fully aft. From that point on (in increasing wind), you're forced to over-flatten the foot of the sail, but should be able to depower effectively until the main traveler is fully eased. After that, things get ugly even with a boom, but especially without a boom, when the Kaos effect kicks in, and easing the main sheet powers up the sail.
In other words, the lack of boom should only effect you in significantly over powered reaching conditions.

As for sailmakers, I'd give Skip Elliot a call. He has lots of Nacra experience over many years, and made a boomless 5.8 sail for a friend of mine, made an oversized square top retrofit for another friend (on a Mystere 6.0). Both my boomless and square-top friends are quite happy with their sails, AFAIK.

--Glenn

heres another WRCRA 6.0 with smyth sqtop and big jib.

Same boat with Racer X sails