Towing Generators / Update, Anyone?

[Ram]

Originally Posted by 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....

What do you mean had trouble with the rpm speed? could you use a bigger prop?

[Captain Bill]

[QUOTE=s/v Beth;370749]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.

Did you try the original propellor and mounting shaft? If so, did you have any luck. I clearly see from my experiment that you would have to turn it at about 1000 RPM to make 12 volts and maybe 12-1400 to make enough voltage to charge a battery directly. Given the amount of slip that is likely that is probably pretty unlikely. That is why I proposed coupling the output to a buck converter. It can take lower voltages and convert them to a constant output voltage at the expense of amperage. Buck converters can be on the order of 90% efficient. Lets assume that the 10 amps off scale reading I got was in fact 10 amps at 7 volts or about 70 watts. A buck converter could give you about 4.5 amps at 14V to charge the battery. Not a huge amount, but useful.

[BarnicleBill]

the trolling motor conversion is on the right track .I think what is needed is a variable pitch prop ? I've built a few , very crude hand adjustable for experiment purposes for some modeling projects.you will need a lath to turn down a hub to afix the prop to the motor, generator .
you 'll need a brass pipe thread tee in 1/8" or 1/4" and 2 pipe plugs. afix ,soder or braze some flat brass or steel stock to the pipe plugs, or easier yet use a short brass pipe with slots cut length wise for a more robust prop blade .when you make the blades any size , shape , length just clamp the blades togeather shape to your hearts content
now just screw your pipe plugs into the tee untill tight and ajust with a home made angle gauge
as a side note I still use the frist one i made as a paint mixer ,it will clear a 5 gallon bucket of its contents in about 3 to 4 seconds with a 18v drill .
HAY -do you think! ???? naah that wont work ? move the boat around LOL

[ka4wja]

MaizieDerrick,

I have good news for you......
I'll post the highlights here, along with links to further info and discussions....

Originally Posted by MaizieDerrick

..has anybody ever made them commercially? does anybody have any good words for them?

Yes, and Yes.....

1) Yes.....
Hamilton Ferris has been making their towed-water-gen for many years (20+), and I installed one a few years ago on my current boat (which works great!) and have used them on other boats years ago as well (where I also had good results)
Alternate Energy Power Products, wind generators and solar panels
Wind Powered Generators

I have no experience with the Duo-Gen (which was mentioned by some others here), but have heard that their output is about the same as the Hamilton Ferris WP-200, despite their claims of higher output.....and they are pricey as well as being fairly high maintenance units.....


2) As for "good words" for them.....
a) Yes, I myself (and many others) have had good results with them......
The DO work.......although there are sailors that mention the fact that since you may be out on passages only 5% - 10% of your time, the expense of a towed-water-gen sometimes doesn't make sense....
But, if you talk to those that have one, and use one, you'll find that they DO make life nice and easy at sea, especially when the sun isn't shinning much and hence solar panels aren't producing too much power....

b) My personal experiences, most recently sailing across the Atlantic a couple of time in the past few years, on my 47' sloop, are:
Boat speeds < 3 kts = battery charging is < 3 amps....
3 - 4 kts = 3 - 4 amps....
from 4 kts to 7 kts = 1.25amps/kts to 1.5 amps/kts.....
And at my typical 6.5 - 7.5 kts = 8 - 11 amps

c) There is NO noticeable effect on my boat speed at all, at boat speeds of 4 kts and above.......I suspect I may be losing < 1/4 of a knot at most, but I've never noticed any change at all....
In light winds, and lower boat speeds, I'd say plan on a slight, 1/4 kt, effect at most....

d) I have experienced only some minor chafe at the line terminations, but nothing severe....except when I didn't have the line running fair (my fault).....


3) Have a look at my set-up here.....
Towed-Water-Generator
and
Annie Laurie Translant
and
Solar Panels


4) For a LOT of great info, and advice from those who use towed-water-gens.....Read over a couple of discussions on the Seven Seas Cruising Association's disc boards here....
http://ssca.org/phpBB3/viewtopic.php?f=6&t=8685
and
http://ssca.org/phpBB3/viewtopic.php...=5801&start=15

(but try to ignore the naysaying from those who have not used a towed-water-gen....)


I do hope this helps....

John

[Ram]

Nice post John and i remember you posted a few of those pic a few years back-nice to see more- very nicely done!

[MaizieDerrick]

aloha.. well almost twenty years have passed for us since our cruising life and seems the only things thats changed is the cost..solar panels i would have thought would have gotten cheaper with mass production and made in china stickers everywhere..gps though is definitely affordable.. well if you own a boat nowdays whether your retired or just into boats you gonna have to face up to spending lots of that green stuff.. but its still neat to experiment with stuff in the hope of saving a little money and to say in this modern age that you built something yourself.... this is a little backwards but how about some paddlewheel assembly mounted or towed... wonder how efficient paddle wheels are? after all it was only one hundred years ago thats what we were using to move ships...derrick

[s/v Beth]

Capt Bill and RAM- the problems I encountered were- not enough rpm on the prop, and really not the right prop. The plastic one on the trolling motor just flexed too much to really be a good transmission of power back into the circuit. I did not use a Buck converter- I quit before that point because i felt like I really couldn't get enough power from the system to make any difference.I did use the system to motor out of the marina, but then gave up on the regen part.

[senormechanico]

We had a Four Winds on our previous boat. The water generator option came with a SS shaft about a meter long terminated with a 3 blade propeller similar to what you would see on a 8-10 hp outboard. It was mounted "backwards" so the water pressure would push on what would normally be the back side if it were mounted on an outboard motor. The other end went to a double braid line which attached to the permanent magnet motor.

We didn't want to bother taking down the wind generator just to use the water option, so I found a PM motor at a salvage yard. After hooking up my multimeter to several, I found one which would generate the most voltage when I spun the shaft with my fingers. When attached to the stern rail, it provided about 6 amps at 5 knots.

My impression of any sort of transmission in a home made rig would be that friction of any kind would greatly hurt the charge curve. The losses would be significant as there is not that much power to be harvested in the first place. In other words, find the right motor in the first place rather than going for voltage or rpm conversion.

[s/v Beth]

I agree senior- the key is in the right motor. I have a bike assist motor that generates at a very low rpm- somewhere around 60 rpm, but it is in a large pancake and probably unsuitable for the boat (I am still looking at it) I also think the power train from the prop to the motor is very important- too large a loss in efficiency will may the whole project go down the tubes.
that said- I would that you go ahead with your plans on a trolling motor. I will not get too excited however until we have a working system. I am not negative about your ambitions...I think we should try anything and see what comes out in the wash. This is just my 3 year in dealing with regenerative energy and personal transportation. Most of it has been on custom recumbent trikes, but I have my hand and mind in sailing too.

[Euro Cruiser]

Here's a suggestion: Those of you eager to tinker could get past the 'maybe this would work' stage by downloading the Ampair water generator's manual and read the section on the type/size of motor they are using. This unit has been in production for several decades. It may be equivalent to their Ampair 100 wind gen unit but I don't think so, as I mounted an Ampair wind gen some years ago and recall it not being nearly as heavy as the water gen unit I just mounted aboard WHOOSH.

Another option is to look at the 'regular' (not high-speed) prop being used on Ampair's 3' stainless shaft. I'll try to attach a pic of it to this post. The prop is ~9.5" diameter.

Jack

[s/v Beth]

Jack- how does that work- the prop spins the rope which evenually torques the generator? Or is there more to your outfit than meets the eye? Looks nice and simple. Price?

[marujo.sortudo]

These type of gens are much cheaper and simpler than the Duogen. Cons are: reduced performance, skip out of the water at higher speeds, often difficult to retrieve, and occasionally eaten by big fish. No, really! Ampair base unit is about $1200, with regulator, mounting and spares, it's well below $2k.

[ka4wja]

marujo,
In just the last couple of years, I have over 10,000 miles offshore using the Hamilton Ferris Towed-Water-Gen, on my 47' sloop....and have used their unit on other boats over the past many years......

Please excuse my bluntness, but some of what you wrote is myth, not fact....

Originally Posted by marujo.sortudo

These type of gens are much cheaper and simpler than the Duogen. Cons are: reduced performance, skip out of the water at higher speeds, often difficult to retrieve, and occasionally eaten by big fish.

Yes, they are much cheaper and easier than the Duo-Gen......but the rest is myth....

If I may answer them in order....

1) "reduced performance"......compared to what????
If comparing them to real world performance of the Duo-Gen, they do NOT suffer from "reduced performance"......

Although, everyone should be aware that the "standard" prop and shaft supplied can be changed to a higher or lower pitch, if your needs demand it (such as on a much smaller or much larger boat), and the shaft can be supplimented with bronze weights to allow for varying conditions.....

If you use a towed-water-gen (either Hamilton Ferris, or AmpAir) correctly, they do NOT suffer from any reduced performance....

2) If you choose the correct prop, and/or the correct weight on the shaft, they will stay submerged......
Although, changing conditions can still have an effect....and I've found mine working fine one night (with ~ 8' - 10' seas), sailing at 6.5kts, and the next day with seas twice as big (~ 18' - 20') and sailing downwind at 8.5+ kts, it will fly out of the water occassionally....but not very often....and even then, there is no trouble / problem.....(If I want, I can pull it in, and add a bronze weight, and all would be fine again....)

The short answer is:
If you use correctly, you'll not have any problems with it flying out of the water at all!!!

3) They are not difficult to retrieve at all.......this is an absolute myth.....
I can retrieve mine it about 30 - 45 seconds, in the pitch black dark of a cloudy/moonless night, with heavy seas (> 16'), completely single-handed....while sailing at speed (7+ kts)
I've done it a few times, just to be sure!!!
And, I've also had my siblings (untrained crew) do it as well.....and there is NO problem at all....
NO twisting of the tow-line, NO hassles, etc....

If you use the "retrieval funnel", all works well.......but, even if you do not (I lost mine in a tropical storm once, and didn't have a spare), you can retrieve it with some difficulty and quite a bit of twisting of the tow-line....but it can be done, while still sailing along at speed (7+ kts).....
Also, you can make your own "retrieval funnel" out of any large galley or engine room funnel.....


4) I've never lost one to a big fish......never!
I know that some have lost their towed-prop and/or tow-line, and have attributed that to "big fish".....
But, I find that highly unlikely.....
Most probable is that there was some chafe that was not noticed and/or repaired, and the tow-line simply parted under load.....

Please note that I cannot say to a certainy that big fish do not eat them, but it is very unlikely....


I hope you don't mind me being this blunt.....
But, if you read the SSCA disc board threads (that I referenced earlier), you'll see a fairly detailed layout of the facts.....


Fair winds...

John

[marujo.sortudo]

John,

Thanks for the experience and in-depth rebuttal! I appreciate being called wrong here by people, because they're so much more forgiving than Neptune!

First of all, let me say that I have NO direct experience with towed gens and all of my notes are based on my own research, AKA hearsay. I do nevertheless take issue with some of your points! (The nerve of this guy )

1. If you compare manufacturer literature, this is what you get at 12V:

Aquair 100 - 2A @ 4 knots, 4.5A @ 6 knots, 5.3A @ 10 knots
Duogen-2 - 4A @ 4 knots, 7.5A @ 6 knots, 20A @ 8 knots
Hamilton Ferris Waterpower 200 - 5A @ 4 knots, 12A @ 6 knots, 19.5A @ 8 knots

I had assumed the Aquair was representative, but apparently it is not. The Hamilton Ferris has much better numbers. Interesting... I stand corrected!

2. I have heard of this being a problem with some of them, but if they can go up to 8 knots that's more than I'll ever need (hopefully!) Perhaps some manufacturers have solved this problem better than others?

3. Certain skippers have reported this online (no I didn't save the links), but this may be as much of a skipper issue as an equipment issue, I can't say. I do remember that one of the postings specifically sited a funnel not working for them.

4. I did see one posting where someone reported the prop coming back with teeth marks in it, and there are multiple postings on the very links you provided that suggest that fish did get some of the props. Many postings suggest that the main problem is chafe which makes total sense to me. One post did describe the mount being partially ripped out which sounds like more than chafe, but who knows what it was. The only important point is this: you better carry a spare prop and line.

Fair enough?

Cheers, Colin

[Euro Cruiser]

Newt, yes it is that simple. The most difficult pieces are a reliable method for retrieving the prop & shaft when they are spinning away & a lot of inertia is involved (the most common choice seems to be running a big funnel down the line to stall the prop) and the need to be thoughtful as you deploy the string & shaft/prop assembly (so it doesn't catch on itself).

Colin, in researching my own tow gen choice I've received a lot of reports, like John's, from users of both the H-F and Ampair units. I've found no in-the-field confirmation that the two produce significantly different amp amounts and, probably like you, I've found that manufacturer's claims on all kinds of marine gear are 'optimized' at best, if not exaggerated...so I wouldn't hang my hat on what you are reading. The Duogen may in fact produce more output as its separately marketed wind gen product produces far more amps than the more common choices we read about here. However, the Duogen is twice the price (at least) of the Ampair I bought ($950 from Marine Warehouse), had many performance/design problems among those doing Atlantic Crossings the year we were leaving the Med for the Caribbean (saw several in dumpsters), and its wind gen output is weak. Also - at least for some of us with boats like WHOOSH - dedicating the space needed on/near the transom to deploy/stow the unit can be difficult. The main point here is that none of these units are ideal, they each have their compromises, but that the best way to choose between them (if at all) is to talk to folks who've used them for many sea miles.

The 'Fish ate my tow gen' stories are, from everything I've heard/read, bogus. Especially with the H-F unit (but also the Aquair to a lesser extent), chafe can be a big problem where the tow line joins the generator and the shaft. You can read multiple accounts of this - and efforts to resolve it - over at the SSCA DB. I'm sure there have been times when boats have been offshore, in the presence of big pelagic species, and lost their shaft & prop. But if you felt the weight, saw the dimensions of the shaft and line involved, and could appreciate the inertia of this quite heavy assembly, spinning to beat the band, you'd conclude that chafe, perhaps aided by fouling on some floating junk, is the far more likely culprit.

Finally, props don't 'jump out of the water' unless the wrong pitched prop is used for a given boat speed. The Ampair unit e.g. is offered with two props, one for use above 8 kts and the other roughly up to that speed. For most of us and most of the time - sadly - using the a normally pitched prop never produces this problem, which does need to be avoided so as not to have the shaft/prop assembly foul the line.

Jack