Boomless rigs

[samin 0]

Once upon a time Planes had two lifting wings at the front, lots of wires and struts. Aeronautical engineers have moved on. Pity we can't.

 

 

I agree - freestanding masts are the way to go

 

for a cruising boat, great but if you wanna win a race, your dreaming. Or is there a successful unstayed race boat somewhere iv missed?

[Guest]

There was a french one cleaned up the Admirals cup but got banned (yachting administrators tend to be somewhat conservative and reactionary).

What sort of racing? Wylie cats regularly win short handed and single handed in San francisco against all comers.

But cruising is sooooo much smarter than racing, why bother?

 

Most racing boats are built to a set of rules that tend to prohibit innovation.

Read this

 

http://www.sponbergyachtdesign.com/Copernicus.htm

 

Or just this exerpt

 

 

 

In the end, the new free-standing mast weighed almost exactly the same as the original rig with all its associated rigging. It probably could have been lighter as I think we could have used less wood. Bryan and Carey report that the boat sails faster, points higher, balances better, and is just a lot more fun to sail than it ever was before. It is a completely different boat. With the old stayed rig, they could never catch a friend’s Beneteau 37 before. Now they sail past him with only the mainsail up, and they point 5° higher.

 

 

Another quote I like:

 

C.A. Marchaj, again in his book Aero-Hydrodynamics of Sailing, bemoans this state of affairs:

 

Certainly the rating rules have in this respect a more profound effect on the shape of sails than the aerodynamic requirements or wind in all its moods. The penalty incurred for example by the sail measurement system on the width of the headboard of the mainsail or length of its top batten is so high that it virtually precludes any attempt to improve the aerodynamic effectiveness of the modern tall rig. Those curious prohibitions, which after years of enforcement became part of sailing tradition, effectively discouraged ocean racing people from making experiments with unorthodox rigs which could have led to the development of less tall but more efficient rigs. So triangular rigs prevail.

 

 

 

 

And they are safer.

[Guest]

Krazy K Yote was the french admirals cupper.?????

[Guest]

Gray Wolf (Seattle I think)

[markm 30]

With the old stayed rig, they could never catch a friend’s Beneteau 37 before. Now they sail past him with only the mainsail up, and they point 5° higher.

 

A beneteau 37, hmmm, me suspects the benchmark in state of the art performance 37s is a little different south of Weiti Squid.

 

 

Not quite with the Admirals Cup. It didn't race so 'cleaning up' is somewaht speculative. The reason it didn't is that the owner spat the dummy after the final IMS handicap came out higher than the earlier provisional one, whilst yachting administrators may be conservative it would seem they take second place to temperamentalFrenchmen who prefer not to understand the meaning of provisional.

[MartinRF 54]

Browsing this thread I suddenly realize I have sailing experience of both boomed and boom-less multihulls and some aspects of these have not yet been highlighted. Here are my two cents:

 

My first cat had a boom-less mainsail and my current cat has a boom. These boats are so different (Wharram with sprit-sail vs. Spyder with fully battened, square-top, carbon main on rotating spar) comparing them is meaningless. The old boat would not have been better with a boom and the new one would need major surgery to both structure and sail-plan to achieve boom to boomless conversion.

 

Other boom-less boats on my sailing CV include a highly modified Telstar 26 (horrible boat) and an RC27 with a sail plan optimized for Swiss' lakes (440 kg boat with some 100 m² sail). All Bill Robert's cats are designed for boom-less mains I think and I never felt like we needed one on that RC27. The RC27 is so quick we were always sailing close hauled so there is no need for a curved track.

 

Now to my thoughts. Let's start with the photo on my web's front page:

http://hem.bredband.net/b262106/

The clew of the main is just hooked to the boom so a sheet pulling in the same direction as the hook would result in the same sail shape. The problem is of course this sheet need a track somewhere aft of the boat. Hence, a boom gives the designer more freedom in designing and placing the sail plan on the boat.

 

Another issue is reefing. You see no blocks or reefing lines in that photo and that is how I had it for many years. We simply lowered the sail to the new height and re-hooked the boom to the 'reef-clew' and re-attached the down-haul to the 'reef-tack'. This was easy enough as long as there was at least two of us and the helm could sail the boat on a close-hauled heading under jib-power while the main was un-powered. It was even a rather quick maneuver and it must work the same on a boom-less boat. These days I sail singlehanded most of the time and I never managed to make this procedure work. I thought some practice was all that was needed but eventually gave up and added 'traditional' reefing gear to my boom. I don't know what you do in this case on a boom-less boat. (Autopilot I hear you cry and that might be the answer. I never tried that.)

 

Mast rotation next. My boat as are surely many of yours is set up beach-cat-style when it comes to boom and mast rotation so the boom helps the mast rotate into position. Without a boom you need to rotate the mast manually every tack and gybe (or??).

 

Head injury is a real possibility with a boom. I remember reading a piece on this many years ago. It was written by a British neurosurgeon and sailor. After an boom-head incident on a boat he crewed on he did some research and found serious boom-head collisions were much more frequent than he had thought. Food for thought no doubt, at least for monohull sailors and those multihull sailors that spend maneuver time in vicinity of the boom.

 

Tuning? On a boom you have an out-haul for flattening the foot of the main. For a boom-less main I would try the opposite, an in-haul for making the foot deeper. I have not tried this (the RC27 didn't have this but with speed like that who needs deep sails?) but why souldn't it work? The sail does not know how the resulting force on its clew is generated, it just obeys.

 

A final note on that photo: We are going down-wind under asymmetric spi, jib and main. The main traveler is dead center on its track. Sailing singlehanded I would not hot things up like this and would use more of the main track

 

/Martin

[Guest]

Krazy K Yote was the french admirals cupper.?????

 

http://riggingnews.blogspot.com/2010/05 ... -past.html

 

Does have a boom though.

 

 

But the article does explain why we don't see too many innovative ideas in yacht design.