energy recovery while sailing

[kriz]

I'm new here, so please correct me if I'm at the wrong sub-forum...

I heard it's possible to extract some energy by propeller on a sailing ship
I think the idea fits best with a controllable pitch propeller connected to an electric propulsion unit (then acting as generator)

I searched the www, but the results were very poor
probably my keywords? (propeller, energy, recovery, sailing,...)

I would like to now the potential of this technique
can somebody help me?

kris verstuyft
masterstudent electromechanical (maritime) engineering @ ghent university (belgium)

[gonzo]

It is a very common concept. However you are not recovering energy. You are collecting it while putting mechanical stress on the boat and slowing it down. Whether that is acceptable or not depends on the application.

[kistinie]

Originally Posted by kriz

I'm new here, so please correct me if I'm at the wrong sub-forum...

I heard it's possible to extract some energy by propeller on a sailing ship

can somebody help me?

kris verstuyft
masterstudent electromechanical (maritime) engineering @ ghent university (belgium)

Welcome Kris !
Cape ! Lets do it !
Very simple principle indeed

First the propeller
Best i saw was 4 x 20Cm² blades tuned to give 1 KW sailing 12knts with under 200 N drag

Second the motor
Connect to the shaft a polyphase motor, get the energy
More generally a rotoverter is any electric motor used as a generator.

Is it a student work you are working on or just for your the knowledge ?

[kistinie]

Originally Posted by gonzo

It is a very common concept.

However you are not recovering energy.

You are collecting it while putting mechanical stress on the boat and slowing it down. Whether that is acceptable or not depends on the application.

So common market is around O :-))

You are recovering Kinetic energy.
200N drag for 6 tons boat going 12 Kts is 1Kw recovered, 0.2 Knt lost.

It is acceptable for racing application, don't you find this nice ? :-))

[PAR]

How may knots are you willing to shave off your sailing speed, by towing a generator prop or free wheeling the ship's prop, V belted to a generator/alternator? A small vessel (under 30') will lose a whole knot, possibly more.

Having towed just these types of devices, the site you've listed suggesting you'll only lose a 1/4 of a knots is optimistic at best and frankly not even close in reality. Small craft (under 30') will lose a full knot from dragging a prop. Of course there's a lot to consider, wind strength, SA/D, D/L the device drag, etc., but I can tell you deploying something that will reduce average boat speed by 10% to 20% is a deal killer, especially on boats that can only muster 6 knots or less.

[alan white]

The idea will work when you have energy to dump---- when there's enough wind that the boat will do hull speed no matter whether the prop is spinning.
Any time you're doing under hull speed, the boat will be slower.
However, the idea is sound if you aren't using too much power. After all, it won't use precious fuel needed to drive off a lee shore or head for a safe harbor. LED lights nowadays use only a small amount of power.
Or you can go without an engine, use an electric drive/generator and battery bank and conserve. If you don't abuse the prop generator (thereby comprimising your speed potential) you can enjoy a lot of conveniences out at sea without dealing with the noise and maintainance of an engine.

[kistinie]

Originally Posted by alan white

The idea will work when you have energy to dump---- when there's enough wind that the boat will do hull speed no matter whether the prop is spinning.....
If you don't abuse the prop generator (thereby comprimising your speed potential) you can enjoy a lot of conveniences out at sea without dealing with the noise and maintainance of an engine.

Yes, this is why you find it on race sailing boats ...most of the time at their hull speed or above
Light sailing boats can be fully free from any fuel as long as they sail.
To drive light and pilot / Electronic from regen, any size light multihull is eligible, big boats above 50 feets will allow several Kw to be produced.
Take a close look to the next Vendee Globe race

[PAR]

Wouldn't it be nice if the batteries didn't need charging when we weren't nearly out of fuel or had enough way on to make the lose acceptable. Reality is often a contrary beast, forcing our hand.

[kistinie]

Originally Posted by PAR

Reality is often a contrary beast, forcing our hand.

Well said
Beast kills energy
Sailing drowns the beasts

Choose the right generator.
The right prop
Sail...Get energy

Just by improving actual generators like alternators, wind mill, Genset, is a fine way to go

Originally Posted by kistinie

Well said
Beast kills energy
Sailing drowns the beasts
Choose the right generator.
The right prop
Sail...Get energy
Just by improving actual generators like alternators, wind mill, Genset, is a fine way to go [/url]

YOU NEVER GET IT Kristine!
It is neither "regenerated" nor is it "for free", and sailing means motoring quite often, like it or not!
Or better learn sailing, then you know!

[kistinie]

Originally Posted by apex1

YOU NEVER GET IT Kristine!
It is neither "regenerated" nor is it "for free", and sailing means motoring quite often, like it or not!
Or better learn sailing, then you know!

You bet i never put it in ? You take risks !
As it is already there.
You are blond for sure.

Motoring quite often ...Yes ! For 10 minutes, 30, 1 hour...more you drive a motor boat !

Electric is perfect for sailing.

[PAR]

Actually, most cruising sailors find a reasonable estimate of sail to powering time is right around 50% of the "in route" time.

Kristine you are an Idiot! Thats it.................

and this would be the right "Hybrid" propulsion for you!



the oarsman part, naturally..............

[PAR]

His reputation is a good indication of what the forum members think about him.

[kriz]

Quite animated forum, lol

The project I'm working on is of a lager scale than earlier assumed: a 34,6 m (120 ft) barque which is a -yet to be built- replica of the polar exploration ship "Belgica".
http://www.belgica-genootschap.be/belgica.php

I'm currently investigating the possibilities for the energy supply on this ecological/green replica, including energy captation by propeller while sailing.

Seen the sailarea, wind power is abundant. What I'm looking for is data about the potential of this (regeneration?) technology: manufacturers, maybe some examples or case-studies,...

And to preserve peace: sailing=sailing, motoring=motoring and cruising=50/50