What's a mast good for?

[dionysis]

Open 60 style hull, say about 7-8 tons, 3 of which is water ballast; no lead at all, twin bilge centerboards as far apart as possible, and twin rudders - selfstanding 30 degree canting wingmast with enough volume to right the boat when it inevitably turns turtle. (As serious mechanics as a canting keel.)

To my mind, there is less chance the mast will break than that the ballast keel would . Handled properly there is little chance the boat would be capsised by wind alone. But waves are another matter.

There is nothing new here, nevertheless I think it is worthwhile considering the idea again in light of new materials and more modern ideas. It certainly would be fast, but perhaps not as fast as it's racing cousins. What do you say?

[CT 249]

Isn't the failure rate of wing-masted cats about 100% when they capsize? Wing rigs are not like keels, are they? They are much greater in area and any weight in them subtracts from stability, so they must be built very lightly and therefore are very fragile. Furthermore, perhaps when you roll, they may well actually act like a sub's hydroplanes when they are set to dive. In windsurfers, you can sometimes see the fairly rigid rigs hit the water and drive deeply into it because of the angle of entry.

[dionysis]

I don't know. As I said, I think the only place (within reason) where you would be in danger of capsizing would be in big breaking seas etc. There would be little chance there that you had your sails up. I was thinking of a self standing rig. They have to be really tough. If such a beast were viable, it would be a small price to pay to have a heavier than usual mast.

I think that the mast would be canted to leeward of wind and waves, and perhaps there would be some tendency to dig in if there were a capsize. But you are right: the mast would have to be plenty strong to withstand the water pressure; both digging in and hydrostatically.

I still think if the mast can be made strong enough and not compromise sailing characteristics too much, it would make a damn good boat. From a theory point of view it makes sense. rom a practical point of view I will have to wait on the judgements of sailors that have sailed large,wide and water ballasted boats.

cheers

[Skippy]

I wonder if that has something to do with under-engineering of keels. It's not the most glamorous part of the boat, so people might not give it enough attention. And some more aesthetics- and/or marketing-oriented producers might not appreciate how highly stressed it is at the base. But weight is virtually a non-issue, so almost any material can be used. Can it really be that hard to make it strong enough?

[dionysis]

It's not the keel we are trying to make strong skippy, but the mast, so that we can get rid of that dolefull heavy thing. I say put the engineering into the mast in a effort to get rid of the keel.

[water addict]

Originally Posted by dionysis

Open 60 style hull, say about 7-8 tons, 3 of which is water ballast; no lead at all, twin bilge centerboards as far apart as possible, and twin rudders - selfstanding 30 degree canting wingmast with enough volume to right the boat when it inevitably turns turtle. (As serious mechanics as a canting keel.)

To my mind, there is less chance the mast will break than that the ballast keel would . Handled properly there is little chance the boat would be capsised by wind alone. But waves are another matter.

There is nothing new here, nevertheless I think it is worthwhile considering the idea again in light of new materials and more modern ideas. It certainly would be fast, but perhaps not as fast as it's racing cousins. What do you say?

If you were to design a wingmast to perform the function of righting the boat when turned turtle, it would be so heavy the boat would flip over without a lead keel. The forces on the rig in the water would be many, many times greater than in the air, since the density of water is about 800 times greater than air.

It's a non-starter.

[CT 249]

I've done a bit of sailing on large water ballasted boats, but only farting about on day sails or short races. Something like Xena alreadly feels a bit worrying when you are transferring water to the leeward tank before a tack or gybe, without the lead she would be terrifying. In comparison the more conservative VO 60s feel much safer without water.

You definitely have your sails up some of the tme in big breaking seas, otherwise you can't get anywhere (apart from drifting to leeward) and you roll your guts out and you are a sitting duck for any breaking wave. Lieing ahull does not seem a good technique for storm survival.

Of course, you could leave some water on the "old" side before the tack or gybe - but when you transfer the water later, what happens when you accidentally tack? It happens, at night in those freaking 'orrible Bass Strait waves, even to good boats like Ragamuffin and IIRC Xena. Xena's knockdown in the Hobart didn't sound at all fun, what woould have happened without some lead in the bulb? How is going to pump water from side to side at 3am when the boat is heeled over to 110 degrees or more (depending on mast cant) and everyone is hanging by their harnesses or struggling to get from the old windward rail to the surface of the water? Can you rely on the pumping system? Will every valve and control work after the boat has been picked up, thrown around and over?

Early cats and tris carried masthead floats to prevent inversion, AFAIK they rarely worked and often brought the rig down. Wing masts are not that new an idea, first ones i can recall were about 1948 or earlier. They can be cool (two of my boats have them, one may get one) but the advantage in efficiency is not worth it on a cruising boat IMHO.

[dionysis]

Thanks CT 249, that's the kind of information that I am looking for. Pity though - it seemed like a good idea at the time.