Towing Generators / Update, Anyone?

[LuvToSail]

one I have heard of

an old motor from a reel to reel tape recorder
a small shaft (2 feet long) with a loop welded on to tie onto
a prop off a 2hp outboard
a some poly rope to connect the motor (i.e. generator) to the shaft prop

a cone (funnel) to slide down the rope to stop for pulling in

i heard this works great and takes only off 1/4 to a 1/2 knot

[MaizieDerrick]

aloha ..appreciate the response.. I never noticed any speed decrease on my vessel but the it was a 72 ft schooner and we just thru on more sail when needed.. on a smaller vessel though I can imagine it could make a diffrence..now the kids have left home and we have downsized to 45 ft so maybe I will have to streamline the next one we make.. I suppose in the vast ocean one shoudnt worry about a little decrease in speed but everyone wants to get there faster nowdays.. maybe we all need to slow down a bit..derrick

[MaizieDerrick]

aloha didnt have much problem with speed in the old days . our 72ft schooner we just piled on more sail so didnt notice anything.. then we had lots of kids to do all the work and now we have none.. well on our 45ft schooner we may just notice a diffrence especially as we will be rather cautious with extra sails and only my wife an I to handle them . old farts no less.. well maybe we have to build a more modern version ,a little more efficient and use a little less power and maybe get there a little slower. maybe we all need to slow down a little and enjoy our planet while we still can..derrick

[Jim Cate]

G'Day All,

In the years 1986 to 2003 we used a home built towing generator on Insatiable I. It consisted of a 32 volt permanent magnet DC motor from an old reel to reel tape drive, about 50 ft of 1/2" double braid dacron line, and a stainless shaft, 9/16" diameter and about a metre long with a beat-up prob from a 6 hp Johnston o/b on the end. When it was new it put out about 4 amps at 5 knots, 10 amps at 6 kts, and more as you sped up, but it would start jumping out of the water at higher speeds. This caused big problems with tangling the tow line, so we tended to strike it at higher speeds. Subjectively it seemed to knock off about 1/2 knot on our 36' IOR shaped boat. The biggest problem was getting it back in... we tried all sorts of cute tricks, including the funnel, and in the long run would just heave to in order to retrieve it. Only took about 30 seconds to hand it in, so no big deal.

For us, having a source of power at night was useful... we've noticed that the solar panels don't work so well then!

Don't have one on Insatiable II, but wish we did... maybe one that used the lower unit from a small o/b to drive the generator so that the difficulties with the towing line wouldn't repeat themselves.

Cheers,

[Euro Cruiser]

We recently researched this Q because we wanted to add water generation of some kind for our Pacific run. In the end, I wrote up a summary of the options available, threads where this is discussed thoroughly, and the product choices we considered along with a few install comments. Some of you know John Stevenson's helpful website and it should appear there quite soon, in this section: South Pacific


Briefly, some of the conclusions I reached after talking to users of these systems include:
-- generally, the more complex (to engineer and install) and costly systems are fixed in place and easy to use, while the simpler and less expensive choices - all tow gens -are more fiddly to deploy and retrieve
-- below 4 kits, all these options produce little power and so their use on smaller boats with lower average hull speeds is harder to justify; from 4-6 kts one generally gets 1 amp/knot, after which the amps climb
-- faster boats need a high-speed prop; Jim's description of his unit prop-hopping at 10 kts is very common unless the prop has a more agressive pitch
-- speed loss has never been reported to exceed 1/2 knot and usually its indiscernable for most boats and most wind ranges

There is one other conclusion I reached and that is the believe that there still exists the opportunity to produce, with the hardware which already exists, an optimized water generator. It would be based on Ampair's UW unit (Ampair microwind, microhydro, and small wind power systems.), fixed and raised/lowered from the transom (but also removable when laying up the boat), and easily installed electrically, all at a a reasonable cost. Unfortunately, it's a chicken/egg dilemma: many are eager to consider solar, wind and portable generators but few think about a water generator (and of course, not many of us intend to do lots of open water sailing so it naturally appeals to a small audience) but few demand the optimum water gen solution...and so the weak demand insures limited supply choices.

Any motivated entrepreneurs out there?

Jack

[DaveOnCudjoe]

Derrick, Back in the day(early 80's) Fourwinds Enterprises offered a towing option for their wind generator. They are still in business but I don't know about the optional tow package. Wind gen is about $2300 US. In those days the choices were Fourwinds or Windbugger. boat show">Miami boat show is coming up in Feb I believe and I hope to make it up there this year. I've often wondered about rewiring a trolling motor for charging but haven't gotten beyond the wondering stage. Dave

[bobfnbw]

Originally Posted by marujo.sortudo

This is the English one:

Water and Wind Marine Generators, Welcome to DuoGen

Pricey, but it seems like the best, too. Most of the others have a similar design to the one pictured higher in this thread and have more speed loss because of the extra drag of the line. If you can figure out a way to do something like this DIY and inexpensively, I'm sure lots of folks would be interested....

Yes thats the one! Here is a link to the us supplier. Cost is around $3300 USD
Check out the specs. It functions as both a wind and water generator. No towed props. Easy to deploy and retrive. There is a video of it. Pretty quiet they say... Easy to install.

Looks very good, if you can afford it.

Bob

[Ram]

I've often wondered about rewiring a trolling motor for charging but haven't gotten beyond the wondering stage. Dave[/QUOTE]

I also just started looking at that as something that might work- anyone know is it possable to rewire a trolling motor into a gen?

[Fishman_Tx]

Trolling motor...
Now there's a thought.

...but it would start jumping out of the water at higher speeds.

try a downrigger?

[Ram]

I was thinking on mounting it to the hull so it could be lifed out,that would elimanate the jumping out of the water problum- I wonder how many amps could be produced from one?

[Euro Cruiser]

Hamilton Ferris does offer a tow gen. Anecdotally, there seems to be more failure reports with that unit than the Ampair, it's a bit more expensive, and the way in which the tow line connects the the unit is a bit more problematic. The SSCA DB has a thread which discusses these issues, if anyone wants more info.

The Duogen gouge seems to be that it performs relatively poorly as a wind gen, easier to use (than line towing) as a water gen, and the seals have historically been problematic. Also, the geometry of the boat's aft end needs to be considered given how it's mounted.

Jack

[BubbleHeadMd]

Originally Posted by Ram

I've often wondered about rewiring a trolling motor for charging but haven't gotten beyond the wondering stage. Dave

I also just started looking at that as something that might work- anyone know is it possable to rewire a trolling motor into a gen?[/QUOTE]

If the trolling motor is a DC series-wound motor, it would work and it would be easy. You need a voltage regulator, and you need to cut out the throttle control. Generators are simply electric motors. When used as a motor, they are a load on the battery. When they act as a generator, the battery is a load on the generator.

The wiring gets more complex when you start messing with shunt or compound wound motors or AC motors. An automotive alternator is an AC motor with a set of rectifying diodes to convert the AC to DC, then the DC is regulated to 14.5 volts max, to keep you from boiling your battery apart. The other thing about an AC motor or alternator is that you need an initial voltage applied to the windings to "excite" them with a magnetic field. Without that field, the spinning alternator will not generate any electricity.

I have no idea what kind of motor is used in modern trolling motors.

[Captain Bill]

I have been wondering about the use of a trolling motor as well. I just happened to have an old Minnkota in the basement with a bad controller so I decided to do an experiment. These are permanent magnet motors by the way. I put a 600 rpm drill motor on the shaft (no load speed) and spun the thing using the high speed coil. I was able to produce 6.98 volts ( may be wishful thinking on the accuracy of the meter). When I put it on the ammeter it went off my 10 amp scale. The prop has a 4 inch pitch and theoretically would be turning 1800 rpm at 6 knots. Even allowing for as much as 50% slippage it would seem that this has potential. Voltage definitely varied with speed. It would seem to me if one could connect the output to a buck converter this may produce usefull output even at lower speed.

[Ram]

Originally Posted by Captain Bill

I have been wondering about the use of a trolling motor as well. I just happened to have an old Minnkota in the basement with a bad controller so I decided to do an experiment. These are permanent magnet motors by the way. I put a 600 rpm drill motor on the shaft (no load speed) and spun the thing using the high speed coil. I was able to produce 6.98 volts ( may be wishful thinking on the accuracy of the meter). When I put it on the ammeter it went off my 10 amp scale. The prop has a 4 inch pitch and theoretically would be turning 1800 rpm at 6 knots. Even allowing for as much as 50% slippage it would seem that this has potential. Voltage definitely varied with speed. It would seem to me if one could connect the output to a buck converter this may produce usefull output even at lower speed.

Now were getting somewhere, i just looked on Craigs list and found a lot of used ones for $50 and up, likly lower if you bargain them down, I think im gonna pick one up and experment and see what I get

[s/v Beth]

I had a 'kota troller and carefully tried to make this work. I think you will have trouble with the rpm speed, but I still think you should try. I had independently come up with a outboard or down rigged bracket that I would run a prop from. Getting a old outboard transmission may work, I will take a look. Lots of good ideas. In fact, if I can mate a old outboard lower with a motor from a windgen we may get the grail of the electric propulsion....A motor for getting out of the slip that generates well when sailing....