a canter,not

Doug Lord said:- "The mostly water movable ballast that works so well on some monohulls would work on any length boat and is/would be fast,fast,fast"

Well Doug, the proof of the pudding is in the eating.

Way back in the mid 1970s I had a Buccaneer 28 Trimaran which, although designed as a cruising boat, I used mostly for racing.

To that end, during construction, we configured the floats to have 80 gall water tanks built in,in the area under the main shrouds. An electric pump with large dia pvc piping enabled water to be pumped in, out and across from side to side very quickly. The system worked beautifully.

In practice we found it really wasn't worth while.

With the windward tank full we had added 800 lbs to the displacenment of the boat, and this was enough to effect its performance dramatically. In fact the only time we did use it in earnest was in a wild night on Lake Ontario in an overnight race, where two monos lost their masts and three lost their rudders. A home designed and homebuilt Catamaran also broke up and sank.

We were OK but slowed up so much that two big monos crossed the finish line ahead of us. An unheard of situation.

Since then I have considered that any form of BALLAST is simply not necessary on a PROPERLY DESIGNED Multihull.

 

Doug, you are hijacking the gentleman's thread with your fizz on foilers... again.

I believe that you have gone to great lengths to describe these central hulled boats with appendage "floats" as... monofoilers, have you not?

That does not equate to the same thing as a monohull, Doug, by your own definition. Please keep the discussion of foilers to a thread in which the topic is about foilers. Your very own, clever phrase insistence has actually boxed you out of this discussion as it pertains to foilers of any kind.

Now, if you'd like to make a post that has to do with a well-recognized monohull form, whether it has an on-deck ballast system, OR, if you'd like to start your own thread that deals specifically with foilers and their possible use of an on-deck ballast system, then please do. But be so kind as to omit the foiler references on this thread. Just to be clear, that's monohull and not monofoiler.

Seems simple to me, as well as to a bunch of other folks who have contributed to this thread already.

 

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Sounds like some exciting times! I'm sure you're not suggesting that Hydroptere and Spitfire and some of the ORMA tri's are "not properly designed" are you? Properly designed ballast systems on multi's or mono's have been PROVEN to be speed producing factors-and their application on CRUISING and racing mono's and multies is INCREASING all the time.

 

As I have said before I agree that multi hulls are the way to go. If I was twenty I would be building one right now. My proposals for movable ballast are merely Ideas predicated on the basis that from what I have read ,canting keels are effective although prone to catastrophic failure.I also agree that movable ballast is a non starter if it compromises the integrity of the vessel. However I think to dismiss it as use fully out of hand is a mistake. We have added to the complexity of every other system on boats in order to get a little more speed,shallower draft. or a little more comfort.why not the ballast system ? I think its worth exploring . After all we have been moving bodies stones ,sand bags .cargo or water since man first went to sea. I don't think that one of us lead miners does not subconsciously move to the windward side on a new tack. Of course there is the matter of how much gain for how much effort. maintenance and cost. Its an easy matter to tweak an extra line for better sail shape but its another matter entirely to crank 1500 pounds of ballast 20 feet. Any way I have attached a short animation of a system that is basically a hollow dagger board that slides in a case athwart ship of the vessel just below the waterline and above the center board case. The dagger board has openings forward and on either end so that as it is extended it fills with sea water. it also contains a lead weight that moves to wind ward as the board is extended. As the boat heels the extended dagger board clears the surface . When the dagger board is center line the water pickups align with wells containing pumps that discharge the sea water or alternatively the water could be directed to the bilge and discharged by the bilge pump. Catastrophic failure would result in the loss of the lead weight but not affect the integrity of the vessel. There are probably many reasons that this is not a practical arrangement and I am sure I will eventually think of them or some one will point them out, but this is where I have come to for now.

 

That is very ingenious Tim, but it doesn't solve the very basic fault in monohull keelboat design.

That basic fault is the destructive inertial forces produced by the heavy weight in the keel.
These forces, apart from the structural design requirements to contain them, cause the unpleasant pitching, rolling and heeling of the ballasted monohull.

After all who needs to sail on your ear on a spanking sailing day, or suffer the incessent rolling when at anchor in a busy harbour.

Admittedly canting keels allow a slimmer hull and larger sail, while reducing somewhat the ghastly lead weight on the end of the keel. But at what expense and complication for such an incremental increase in ultimate performance.

Not to mention the abomination of having a deisel engine running all the time while sailing, in order to power the hydraulic systems needed.

Stability by Bouancy, not Ballast, is transforming the sailing World.

And not JUST the sailing world.

Even the prestigious Atlanic Blue Ribband Trophy is now held by a large , 200 car, 800 passenger, water jet propelled TRIMARAN.