Canting mast

[san.dam]

This is in regard of performance of a light displacement monohull sailing close windward in fresh air...
<Canting the mast leeward of several degrees and being able to have, at the same time, a high value of rake> what is your thinking about the behaviour of the boat? You can imagine the boat sails almost flat and the mast with angle down and stern...
Thanks for comments.
excuse for grammatical and terms errors...

[SailDesign]

Unfortunately, the boat will not sail flat, as there will still be a heeling moment from the sails. The better bet, theoretically, is to cant the mast to windward, so that the boat can heel and the mast will then be upright to catch the most wind.
Steve

[Andy P]

Originally Posted by SailDesign

Unfortunately, the boat will not sail flat, as there will still be a heeling moment from the sails. The better bet, theoretically, is to cant the mast to windward, so that the boat can heel and the mast will then be upright to catch the most wind.
Steve

And the best bet in reality is to have a canting keel, so that the keel is out to windward providing the righting moment, and the hull and sails are upright. The sails and hull work best like this, and the hull may also work better heeled slightly to windward.

[san.dam]

Thanks Steve,I agree what you said. In fact the boat in question has the "windward option" ,but this no means...
I try to explain myself in a better way. In FRESH air conditions,when you need to carry the mainsail "discharged", can this cant downwind and raking be a valid substitute?
The concept would be the boat sails more flat and all works better, the sails

[SailDesign]

san.dam,
Any time you cant the rig to leeward, you will be inducuing a leeward heel to the hull (unless your keel cants to winward at the same time.) You are still, in my opinion, better off without the canting rig and its higher possibility of failure (compared to a fixed rig).
Steve

[san.dam]

ACC... Keyboard failure!
Continue from above.
The sails are in perfect trimming too,and the discharge effect is worked out by cant down and rear... Perhaps best performance of sailplan (rotating wing mast) ?
Is this a crazy thynking...?
I would like to have opinions.
Dami

[PAR]

Lets take it a step farther, and put two boats together, one conventionally rigged and the other with the canting stick and it's related gear. The center of gravity will be higher because the canting gear will need incredible muscle to lever the pole back a forth. This means some of the ballast will be in this gear not hanging well below the hull as on the conventionally rigged boat. A boat of any size would need hydraulics or electrics to power this thing (read more weight out of the ballast) and some sort of instant control mechanism as having to wait very long for the canting process could be dangerous in some conditions (kiss off some more ballast) Now that this is all in place the boats aren't equal in performance any more having to carry the lower ballast/displacement number. If the number changes enough the sail area would need revising, now you have a heavier, more complicated, more difficult to operate, with a higher D/L lower SA/D and less ballast to displacement ratio yacht.

Which one would get around the windward buoy first Saturday mornings? Would you buy a more expensive J27, and live with the fact it is slower on all points of sail then it's conventionally rigged sister? If so Why . . .

It seems clear you need a better understanding of the concepts, theory and practice of sailing yacht design. There are physical reasons and conclusions in the understanding of flow about the hull and air about the sails that you need a better grasp of. Depowering the main in heavy air isn't so difficult we need to invent a contraption to alter the rig geometry.

[gonzo]

A canting rig could be efficient if it tilted to windward. It would be possible to design a much shorter mast. Also, like on a windsurfer, it would provide lift.

[san.dam]

Dear Par,it seems to me that you consider the stability of the boat as the only factor to get best performance to windward...
How many times during regattas with fresh air is better to go close wind with mainsail discharged,and be full sail in course down? Surely many times.
When you do this,take a look at your speedometer and the feeling with the tiller. Also the effective closewind angle... the boat is less natural pointing the wind (less "ardente" in italian) and you have to do a great work with rudder...
The real trouble is not to use the canting like the mainsail sheet when under instant blow, but to find a better balance between hull,apendages and sails. When under momentaneous severe blow,we have of course
the sheet.
The canting process takes no more time of a canting keel and the management of his canards,why the mast is dangerous and not the same with keel?

[gonzo]

There is and easy and tried system to accelerate with wind gusts. It is a flexible mast. That is what fractional rigs are about. It works well and is self adjusting.

[PAR]

Good point Gonzo, the old cat boats raced with unstayed rigs and solid sticks for the same reason. Canting keels, canting masts (if canted to wind) will add some level of performance to the boat, but at what cost and reliability. If the canting keel was such a dramatic improvement over a fixed high aspect fin, wouldn't every boat with a D/L under 150 have it? The idea of canting the stick to handle any duration of gust seems foolish. If you're over powered, you're over powered and there are several things you can do for this, including tossing a bucket over the windward side with a line to a midship cleat, though not my first recommendation.

I've been in some real ugly conditions and this IS the time you'll find out if the fancy whatever just installed will hold up. As a general rule, the more complicated and out on a limb the designer went with the device (hull, fin and rig design included) the more likely it will fail in heavy conditions. Just take a look at the gear failures in the BOC (or whatever they're calling it now) Their keels don't snap off in a soft breeze! This doesn't mean it shouldn't be tried, but logic would dictate a more efficient sail plan with the cant to windward. The most adjustable main I've seen is the junk rig, all kinds of shape control there, but you'll get your butt handed to you going to wind, gust or not, though a fine performer with the sheets freed up.

Good luck with the out of the box thinking though . . .

[gonzo]

The purpose of the canting rig is to make the boat sail flat. It can be done more efficiently with a canting keel or movable ballast (including crew), because the driving power-the sails-are at a maximum.

[emcmia]

Originally Posted by gonzo

There is and easy and tried system to accelerate with wind gusts. It is a flexible mast. That is what fractional rigs are about. It works well and is self adjusting.

I had a 45ft Freedom with an unstayed carbon fiber mast designed by Gary Mull. Unfortunately, the main was designed without reef points (as per Mull). Under sail, with decent wind (e.g. 20 kts+), as soon as you got the main properly trimmed, a gust would cause the mast to bend and spill out the air resulting in a radical uprighting of the boat. You then had to reset your course and retrim - very frustrating!

[san.dam]

Yes,the purpose is to make the boat sails flat. And the work of a flexible rig is a good and well known solution(many of us sails on fractioned and dinghies).
But lets take a step out of the "safety field"... Even the Freedom has in the core the same concept, but perhaps is properly a less windward attitude when the rig takes his work,the cause of the retrimming the boat needed.
The thread would be not in sense to do a powerful boat (canting keel and similar gears,but lot wetted area and induced drag) ,but to have a more minimalist approach to the trouble. Few and effective hull, few and effective rig.
Have a rotating wing mast,canting and in one word "pivoting" could be one of the ways not yet well explored. If someone has some study of a rig like this,please let me know.

[gonzo]

The minimalist approach is an unstayed flexible mast.