[brian eiland]

MotorSailers, MotorSailors..... They're just not a popular subject. Traditional motorsailers have always been such a compromise, they have fallen into disfavor in the market, and in the boating literature. The term has even had negative connotations for several decades now. Should not today's boats be faster and better with new materials, light marine diesels, and better shapes? Should not this be the sensible alternative, the common sense move up from the beloved family sailboat? When trawler options are discussed, suggestions of boredom arise. A lifetime of sail would be discarded, and what happens when the motor quits? Well, hopefully it won't quit, but one can always sail home in a boat with sails on it. For truly long-range cruising and/or remote exploration, the motorsailer can outshine both the sailing aux and the trawler types.

We need to modernize the motorsailer. The multihull plan-form holds great promises to improve this breed. The long slender hulls of the catamaran type vessel have proven themselves to be real efficient to push under both power & sail. And not only are they efficient, but they can be pushed beyond the traditional hull-length/speed limitations. Just what the modern motorsailer needs, a far less compromising increase in both their sail & power performance, that allows for long-range, and remote area capabilities. In light airs, running one engine often is all that is needed to generate an apparent wind that allows the sails work harder, and the combination can provide much better results than either motoring or sailing alone, …….sailing synergy/harmony, the motor taking over in the lulls and the rig taking over in the puffs.

With ever increasing fuel prices there is a bright future for Motor-Sailing vessels. And here I present one such future concept.

"Sail, the historic implement of world exploration, has within itself many new horizons that beckon for pursuit, but you have to be willing to venture past charted waters." - Gary Hoyt

This quote from Gary Hoyt has never been more illuminating than today when we consider that an inventive and resourceful gentleman, Tom Perkins, has 'ventured past charted waters' to bring us a modern version of the old square-rigger, the DynaRig. He has done it in a big way with a real-life 'proof-of-concept' aboard his innovative and fabulous new 290' superyacht, Maltese Falcon.

I propose that this DynaRig is applicable to a catamaran Motor-Sailer

[lurker]

I wonder if the DynaRig can really combine the downwind performance of square rig and the upwind performance of fore-and-aft rig.

Regardless, how cost effect can DynaRig mast be build? Tom Perkins used military grade carbon fiber. I can't imagine that a DynaRig mast can be build cheaply, at least with present day technology.

[AMG]

Building an unstayed carbon fibre mast will not be the biggest obstacle or cost, but you can not use the same advanced in-mast reefing system as on MF I guess. Something more simple has to be developed but this is doable.

On sailing up or downwind with just one DynaRig, I can see that two would be a little better but on a catamaran you will have a more efficient angle of attack than on a healing monohull? Whatever, this can pretty easily be tested out on a model. If it works, it would also be the perfect RC-model...

[MaxResolution]

OK, I'm guessing it has almost no drag downwind, but it becomes a delicate game of balance up-wind. So the cost isn't so much the structure of the mast, as are the electronics that reel in the upper sails in the event you need to reef.

What sort of motion/wind sensor array would it take to trim her fast in the event of a sudden gust?

[AMG]

Originally Posted by MaxResolution

What sort of motion/wind sensor array would it take to trim her fast in the event of a sudden gust?

If you mean to prevent a roll over, something similar to a fishing reel. Winches with adjustable brakes that release the tension in a dangerous gust...

[brian eiland]

Originally Posted by AMG

Whatever, this can pretty easily be tested out on a model. If it works, it would also be the perfect RC-model...

Funny you should mention this. I put a posting on an RC model forum asking if someone who had a previous interest in doing a model of MF might be interested in doing this catamaran

[brian eiland]

Originally Posted by AMG

If you mean to prevent a roll over, something similar to a fishing reel. Winches with adjustable brakes that release the tension in a dangerous gust...

I think Lars has an interesting point here.

I might also draw you attention to this paragraph in my discription on the website;
Reefing this DynaRig is done progressively from the top down. On Maltese Falcon it was found that the 'royals' themselves (those right at the top) accounted for 40% of the loads on the rig, and with those furled her angle of heel reduced dramatically. The overturning moments on our Dyna-rigged multihull should act accordingly. It might surprise you that the 'royals' on Maltese Falcon are constructed of remarkably light 2 oz Dacron, and are "effectively sacrificed in 80 knots of wind." In other words, it will allow 'blow-out protection' in microbursts and/or unseen severe squalls

In gusty conditions I would recommend erroring on the side of safety and just sailing with reefed royals, and maybe even gallants (BTW, I made a mistake in labeling the sails and will attempt to correct it very soon....the gallants and the topsails should be reversed)

[brian eiland]

Originally Posted by lurker

I wonder if the DynaRig can really combine the downwind performance of square rig and the upwind performance of fore-and-aft rig.

I might suggest you have a look here for a discussion of windward abilities of square-riggers:
http://www.weatherlysquareriggers.com/

It might surprise some folks, that very often the square rigger was not sailed dead downwind, but rather made a series of 'jibes' downwind to improve apparent wind flow over the sails.

[KCook]

Of course the Falcon has 3 masts. My hunch (and I admit it's only a hunch) is that the DynaRig concept lends itself best to multi-mast designs. For a single mast I would prefer a more conventional sail plan.

I think a major factor holding back the multihull motorsailers is that they are not self-righting. Find some way to overcome that issue and bingo! The demand for multihulls would start climbing.

Kelly

[brian eiland]

Originally Posted by KCook

Of course the Falcon has 3 masts. My hunch (and I admit it's only a hunch) is that the DynaRig concept lends itself best to multi-mast designs. For a single mast I would prefer a more conventional sail plan.

I think a major factor holding back the multihull motorsailers is that they are not self-righting. Find some way to overcome that issue and bingo! The demand for multihulls would start climbing.

Kelly

I can also appreciate the interaction that occurs between fore-to-aft sails in a conventional rig, and those that could occur between a multi-masted Dynarig. But usually it's a case of the one sail gaining and the other losing...sort of a cancelling out. A uni-rigged vessel might lose a little in pointing ability, but the far greater savings in money for a uni-rig certainly makes financial sense. And there is considerable less aero drag.

The question of self-righting has always plagued the multihull. In this particular design I believe the mast and the yardarms could be built as watertight (sealed) entities by not requiring the very light weight sailcloths be furled-up inside the mast. Those sealed rigging pieces could provide for floatation in the unlikely event of capsize....in which case she would lie on her side to some degree. This could (and I emphasize 'could') provide for a righting method that would not exist if she were turtle.

I am forever amazed at the powerboat crowd that speaks to this capsizing problem of multihulls without ever looking inwardly at taking some of the power designs offshore in a real sea.

...not a real big sea, but I would not want to be on this vessel in a BIG sea

[KCook]

Actually I suspect we are on the same wavelength on the capsizing issue. The monohull sailing yachts that achieve self-righting with a heavy keel make perfect sense (assuming keel does not decide to take a vacation). However, round bottom motoryachts that rely on very heavy displacement to achieve self-righting have always made me uneasy. Just seems like the extra mass means you are also that much closer to sinking? Druther take my chances with a sound semi-displacement design that can get out of its own way.

Kelly

[MaxResolution]

Yikes, meet your maker! ...I'm almost convinced the single mast motor/sailer could be the ideal rescue craft for the above crew, because, even 'turtled' you still have flotation. Flip a few matresses, and everyone could lay down in the dry. Not real comfortable, but prevents hypothermia 'till the 'copters arrive.

Lars aced the instant-release problem, and I agree that a servo-drive scale model would be very useful for working out the yard thresholds.

This may well lead you to incorporate a flare near the waterline for forward stability, ie: the 'light-bulb' hullform, because I have a feeling she will skirt downwind, and bury herself at the worst point of incline.

[lurker]

So, what is the advantage of the DynoRig?

I don't think that it carries more sail area than a aft-and-fore rigged cutter. I suppose that since each sail is smaller, it is much cheaper to replace the sail though more economical in the long run.

The rotating base mechanism for the masts must be taking quite a bit of load, I thought that would cost quite a bit, no?

[MaxResolution]

Some contend the primary advantage, on a mono, is the lack of your reliance on the actual stays. As she flings to and fro, things that can break will, and so must be constantly inspected and monitored. Assume you had an urgent need to skirt the path of a hurricane, without adequate prep, or provisions.

And, on a Cat, I imagine the pressures would be harder on those stay-points as well as discomforting on a bumpy ride, like being 'almost' strapped-in on a older wooden ferris-wheel. I'll assume Brian has done his homework on the stresses at the hull adjoinment-points, and the contemporary state of that art. But, it's sheer convention to assume the self-standing mast must be constructed with a rectilinear (wood/epoxy) core, which is why I suggested maybe a star-shaped spine, integral to an elliptical riser, yet anchored on an actual 'turntable,' which is sort of an inverse of the Falcon's super-gimble anchor array. Albeit, her designer is way out of my league. Maybe the orbital grouping is a giant servo motor...?

[MaxResolution]

All-up, I've studied boats, (online,) now for a total of around 220 tidal bores, always hinting at my inate desire to leap headlong into the eager, come what may. But for the sucking sound of the US economy, and one too many episodes of "Lifestyles of the Rich and Famous," I would surely remain a land-lubber 'till my dying days!

So, y'all tell me, am I a good BS-er, or what? Fact is, I've barely circumnavigated Walden Pond! ..Who in their right mind would let me aboard their yacht?