Generating electricity - water around the hull/keel

[topmast]

Brian Walker(Passing Cloud) used a synchro mesh out of a truck transmission to engage/disengage the prop shaft from the manual gear box (68' schooner) A pulley on the prop shaft and belt drove a large generator while trade wind sailing The system worked very well . Allowed free wheeling, locked or charging positions.

[duefocena]

I welcome anyone's suggestion of alternate ways to generate electricity aboard whether they know what they're talking about or not. I'm sure the first Marconi rig was viewed with skepticsm but I prefer it to square riggers.
That said here is a discussion a monohuller and I shared awhile back. It involved the lee slip a keel counteracts and that force being used to turn a generator. This was right after the idea to produce a material of solar cells in canvas and sail cloth. When we ran out of tequila other priorities took precedence but both were noble chatter of products certain to be introduced by someone other than us.

[StuM]

Originally Posted by Kelkara

Oh but it is being used for something!!! It's being used to hold your boat in place!!!

If you want to use some of that force for something else then you'll have to let the boat move e.g. drag the anchor.

I can't tell out whether you are serious or taking the p*ss.

I hope it is the latter.

[topmast]

requires utilizing a force for a distance over time.Like tying a log to a big rock and let the tide come in .Log bouyancy say 500 lbs Tide range 8 ' time about 6 hrs .. work out the watts involved ..assume 100% efficient

[Kelkara]

Originally Posted by StuM

I can't tell out whether you are serious or taking the p*ss.

I hope it is the latter.

The post I was replying to wanted to harvest energy from the "tremendous pulling force" between the anchor and the boat. The bit about it being a rolly anchorage was implied from a previous post, which I missed - sorry.

If the wind is blowing and my boat is pulling hard on the anchor (but not bouncing around), there is still a tremendous pulling force in the rode ... but it won't be of any use for power generation (unless it's really gusty).

[valhalla360]

Originally Posted by buzzstar

Another side to the same story. Sails and sailing aside, what about water flow when the boat at anchor? We seem to discuss all kinds of anchoring ideas and problems. What about the generation of power (electricity) by using the forces that act on the hull and keel while at anchor? I have no particular ideas, but it seems the OP and maybe a couple of others might.

The problem with water based energy extraction in anchorages is most people avoid anchorages with a lot of water motion (either currents or waves).

If you regularly anchor in an area with heavy tidal stream, it's certainly viable. 99% of cruisers avoid those anchorages as much as possible.

[valhalla360]

Originally Posted by captlloyd

I don't know about the canting keel idea but I envision something between the anchor and the boat. Tremendous pulling force not really being utilized for anything. We may be straying from the OPs original question or not. As I originally stated before, there may be times when while underway with very strong wind conditions SOME sailors might be willing to trade-off a bit of speed for some power generation by some sort of hydro generator. The mind like a parachute must be open to function.

As I stated previously, the vast majority of time cruising boats are in quiet anchorages or marinas. Most cruisers only wind up in nasty anchorages occasionally and they leave them as soon as possible. That leaves only a very small percentage of the time when such a system would actually be producing power.

With the advent of cost effective solar panels, this is also gradually killing off wind generators as they need 15+kt winds to really generate a lot of power. At 5-10kts they may produce a bit of power but really small amounts given the cost and space they take up.

[Tom--]

As topmast noted this prop driving a generator concept is hardly unknown.

The old standard "Skene's Elements of Yacht Design"
Frances Kerry, eighth edition, page 78, describes such a system as used in two yachts that Kerry was aware of. He notes that a 100 amp generator required a force of 2.4 HP to charge a 12V system. The use of a controllable pitch prop was considered as necessary to optimize the system.

My little boat might note the equivalent of 2.4 HP in drag however a big vessel in the trade winds is a very different creature and these systems have a history of success in such boats.

[SV Windrush II]

My wind generator starts really working at 15-20 knot winds, anything less than that is hardly noticeable. Now that it is howling at about 30 knots, it's screaming along and keeping my batteries topped off, but.... now I can play a tune on my anchor line hahaha

[EWOL Props]

Originally Posted by Carogan

Do you have any sources or links you can share? I have only been able to find info on tow generators - it would be nice to read up on any developments!

This is what is obtained coupling an EWOL prop to a electrical engine used as a generator

http://www.naviwatt.fr/wp-content/up...-HPOWERMAX.jpg

[dlymn]

Originally Posted by Jim Cate

The OP asked for those with more scientific knowledge to comment on his idea. They did so, and it was not supportive. He was unhappy with this.

Seems that we get a fair number of naive questions like this, and when those with the applicable knowledge reply, and it isn't supportive, folks get angry and use the "people used to believe the earth was flat" (or its like )argument to support the poster. An interesting phenomenon, but divisive and non productive.

I suppose that it is "human nature"!

Jim

Or "i'll go wherever the winds take me. I'm not afraid of taking risks" Or "once I've made up my mind, nothing will sway me from achieving my goal" Or "I take life as it comes and never plan. What will be, will be."

[jrbogie]

Originally Posted by Carogan

Wow. This was the type of unuseful remark I had hoped not to see in reply to this thread.



Clearly they are not. That's why I asked the question and is something that I'm interested in exploring (although nobody brought in the topic of "tides" into this discussion)



Apparently they don't work very well because they don't generate much electricity and they need to function at 6 knots or more. The flow rate of water through a towed or prop generator won't be nearly as high as water flowing around, say, the leeward side of a keel.



I'm not sure I suggested that solar shouldn't or even couldn't be used in conjunction with alternative sources. Do you think one should only stick to one technology use for generating electricity - or even for a sailboat? Because I don't.

And the one interesting drawback about solar is - it only generates electricity when the sun is out. The interesting thing about generating electricity using the power of the wind...is that wind is typically created in inclement weather when the sun is often not available.



Why don't you tell me what the "primary function" of a sailboat is? Because maybe the primary function of a sailboat for you is different for other people. In addition, some of us might think it is important for a sailboat to have more than just ONE function. Maybe you don't - good for you. Then find another thread to go contribute something useful to and don't buy a boat that might utilize other technologies other than what YOU consider a sailboat should have as YOUR primary function.

As I said in my opening comment - I figure there are some people who would be interested in exploring a tradeoff of efficiency in return for generating power. After all - alot of people who are cruising do rather enjoy the benefit and comforts of electric power and might find it useful to be able to acquire without having to have to go through the inconvenience of earning the money, travelling and finding a petrol station, and consuming a scarce in supply, polluting fossil fuel.

So how about this - if you have a scientific or practical reason to contribute to this discussion - feel free to share it. But please keep your dismissive comments to yourself because I for one don't welcome the negativity.

After all - there was a time where people like you believed the world was flat and no one could travel to the moon eithe
Thank you very much.

i agree with others here who see that you are more interested in confrontation than discussing hydrodynamics and electrical generation. for a self avowed novice sailor your comments sure do sound more lecturing than inquisitive. that said, sailors in general will go out of their way to shun any drag created in the fluids, air and water, in which our vessels must exist. we'll go to extremes for an extra half a knot and wouldn't trade it for that day's entire electrical needs. a difficult concept to grasp unless you're an accomplished sailor for sure but as you said, you're a newbee.

[John Holbrook]

Interesting questions and I have no expertise here so this a question as much as a suggest. How about a tube running from a point of the hull where there is high pressure (in front of the keel?) to a point where these is low pressure (stern?) with a small turbine and alternator. If the opening was shaped hydrodynamically would this have Nader the performance of the boat?

[senormechanico]

Originally Posted by buzzstar

Another side to the same story. Sails and sailing aside, what about water flow when the boat at anchor? We seem to discuss all kinds of anchoring ideas and problems. What about the generation of power (electricity) by using the forces that act on the hull and keel while at anchor? I have no particular ideas, but it seems the OP and maybe a couple of others might.

I can just see the anchoring story now...

"Last night, we dragged up on the beach and the boat's totaled.
It was only blowing 3 knots when it happened, but we were charging our batteries with the underwater electricity harnessing system.
I guess the drag was too much for our anchor."

BTW, I once knew a guy who insisted that by jacking up the rear suspension on his old Dodge van, that he would get better mileage.
After all, he insisted that he was always going downhill. (True story)

[Cheechako]

The problem with generating energy from the boat moving is that 90% of the time the boat is at anchor and not moving. Sometimes for weeks.