Alternative/Supplemental Power Sources

I think you're right about the technically challenged. Reminds me of the millenium bug, by the way.

Hi,

Pascal- I don't think the loads on a towed sailboat alternator are that great as to rob a few knots.

The ones I have seen trail a rope as a "shaft" so the load can't be that great.

Hi,

The 20 AMPS DC you get out of your towed alernator ain't the same as the 30 AMPS AC you get out of your geberator

First, it doesn't matter what the purpose is, the physics are identical.

That .4 hp (25A at 12V) you produce by dragging some sort of water powered generator drive behind a power boat will require the propulsion engine to produce around .6 or .7 hp additional to make up for the drag of the silly thing and its mounting and drive system if the boat speed remains the same. If you want to convert that into real life, the propulsion engine would have to burn about a gallon of additional fuel every 4 or 5 hours just to run a microwave oven for about 10 minutes.

All the work in the world won't change the equation.

Here in Guernsey we have an Aero engineer who has built his own Cat, about 42 foot, that is wind powered.

No sails involved, it has a rotating mast and 3 turbine blades, that drives a hub. This then drives a hydraulic pump that drives an underwater gearbox in a bulb that then drives a large multiblade prop.

With this set-up he can 'drive' straight into the wind. He still has normal wing engines.

I've seen it work correctly once in 8 years.

my small comment ...

for some hundred of years the people try to find a perpetum mobile.

Every change of medium in an energy flow has a lost part.
There a a lot concepts to power a ship from sail to atomic.

Getting 20amps says nothing, 20A with 12V or at 240V?
You can get 20A with 12V ( 240W) from your tuged prop.
You need 30A with 120V in your ship (3600W). This is the difference!

If you have free power (sail), so we can use a wind mill etc.. to get free electric power. But - if you have a powered ship ... using the energy flow over outboard water to catch some energy back ... brings me to smile (see my 1st sentence).

The best is always to REDUCE the lost energy part. Burning oil is not effecive bc we produce to much heat.

thats my cents for you

Hybrid Trawler/Motorsailer

Sounds like you gentlemen are talking hybrid trawler/motorsailer


...New Age Trawler/Motorsailer

Motorsailer response

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.

...more discussions here:
Motor and Sailing Vessels, Motorsailers

Everybody here with practical experience in motorsailors, raise your hands....

Aha. I thought so. Looky here:

The client was comparing trawlers to...motorsailors, generally, and in particular, Nordys to Cheoy Lees. The CL 63 won hands down (sorry) in the interior volume department--master stateroom size, headroom in the engine room, and on and on--compared to a N62.

With one of the two 3208 NA 210 HP Cats shut down (freewheeling LUK props), the boat cruised at 7 kts on a dribble of fuel.

Sail management? Oh, heavens, the husband/wife team wore their pinkies to the bone pushing the buttons for the roller furling jib & the in-mast furling main, and the mizzen was, more or less, just along for the ride.

Why sails + motoring? The sails replace the active stabilizers in keeping things steady and Maw happy...with a lot less attendant cost/maintenance and, ahem, power required to run them.
Hubby & wife were relative novices at the game, but managed to figure it out.

Oh, and no need for a get-home, either.

Wind generator at anchor provided an extra bit of juice. Underway, these folks would run one of the two gensets for 45 minutes in the morning to make freshwater and cook breakfast, then an additional 45 min. late in the day for dinner and to run the A/C. Good hull insulation kept the innards cool all night long with the help of some 12VDC Hella fans. Invertors + plenty of batteries for other needs.

You get the idea.

Yes, they are a strange breed of boat. 45 degrees upwind is about the best they can do, but that ain't a lot more than what most non-racing sailboats can do.

OBTW, that CL mentioned was a twentyfive-year old design--canoe stern, freeboard up to there--very dry on deck in bad weather and a boat that many have gone around the world in with aplomb. CL built a 53, 63, and a 78 which, from a mile off, couldn't be told apart.

The mind boggles at the potential of a truly modern esign... freestanding carbon masts, modern sailplan, etc.

Maybe there will come along some non-XBox yachtsmen/wimmen to see the light.

My $.02

Being able to save energy is better than the need for generating more ? Less weight, more efficient hull / propulsion forms, less wind drag from superstructures (getting rid of those bloody active fins / gyro-stabilisers) etc etc.
However, I can think of a couple of by-products of a hard driven motor yacht that could create energy without increasing drag or increasing fuel consumption.....
Main engine exhaust outlet....get a 'turbine generator' in there.
Negative and positive G....fit fluid filled dampners under heavy objects (chain locker floor, engines, fuel tanks, battery banks, owners mattress, skippers helm seat etc) connect to a reservoir / one way valve one end and 'hydraulic generator' the other....negative G at the crest pulls the fluid in, positive G in the trough pushes the fluid out under pressure.
Engine room air intakes....surely the air rushing in through the vents can drive an 'air driven generator' ? The spinning blades would also make a cool coalescer water separator too.
'Methane fueled generator'...connected to the waste tank.
Its ok, I'll stop now

Like this ... ?

http://library.abb.com/global/scot/scot271.nsf/veritydisplay/a30a1afe92088c06c12573d9002fa018/$File/58-61%204M804_ENG72dpi.pdf