Portable gas generators

[Kaa]

Does anyone have any experience of using a portable gas generator on board of a small sailboat?

I'm thinking of swapping my outboard for an electric trolling motor, but would like to avoid tons of batteries. A small gas generator (say, 50-60 lbs, 1000-2000 Watts) will allow me to use one, at most two batteries, and at the same time effectively free me from limits on electricity usage onboard.

I'm worried about it's ability to survive in the marine environment, though. Any ideas or comments?

Kaa

[Tylerdurden]

Honda, Hands down. One is going on my boat along with the wind genny. Launch it in the dingy on an extension cord if you must but really they are quiet.

[Bob Cleek]

If you absolutely must have 120 VAC, yes, they can be handy, but aren't designed for the marine environment. If left aboard, expect it to turn into a pile of rust in short order. Then there's the gas you'd have to carry and the cost of it. Have you considered how long you'd have to run the generator to charge your batteries? What the generator, batteries, electric motor, etc. etc. etc. will weigh and where you will stow all of them?

Look, this is a matter of faith. I know few of the younger generation have any experience with the concept, so I'll explain it. Do you really think that you, all by yourself, apart from all the experienced people in the world, are really going to have a good idea nobody else have ever had before?

Well, yes, we all think that sometimes. Good ideas do come along every so often and shouldn't be summarily rejected. So, when you begin to seduce yourself with that thought, ask yourself, am I thinking of a solution to a problem anyone else has ever encountered. If the answer to the second question is yes, the answer to the first has got to be NO!

A whole lot of people have considered the problem you are considering. If there was a better solution than those already available and universally accepted, somebody would be selling it by now. Take it on FAITH.

[crawdaddyjim50]

Generators on a small boat is a recipe for disaster..

Death by CO
Death by fire
Death by gas explosion
Death by next door neighbor

So many ways to go bad wrong

[Tylerdurden]

Try the electric boat group on yahoo. Many have been doing this for years. Both me an Steve met a cruising couple last summer on a 40' sailboat who used solar panels a wind genny and a small Honda generator. Both the solar panels and generator were on their fourth season between Canada and the Caribbean.
They both looked happy and healthy. The wind genny was the latest edition that season.

I am running 6 golf car batteries. An Air X wind genny and a Honda 1000 watt as an back up. Don't know if I will have time to convert the outboard to electric this season but it will be electric by next.
Oh I left out the 3000 watt inverter.
Of course don't try anything new, you may put buggy whip makers out of business.http://www.woodenboat.com/forum/images/icons/icon10.gif

[redbopeep]

Look, this is a matter of faith. I know few of the younger generation have any experience with the concept, so I'll explain it. Do you really think that you, all by yourself, apart from all the experienced people in the world, are really going to have a good idea nobody else have ever had before?

Well, yes, we all think that sometimes. Good ideas do come along every so often and shouldn't be summarily rejected. So, when you begin to seduce yourself with that thought, ask yourself, am I thinking of a solution to a problem anyone else has ever encountered. If the answer to the second question is yes, the answer to the first has got to be NO!

A whole lot of people have considered the problem you are considering. If there was a better solution than those already available and universally accepted, somebody would be selling it by now. Take it on FAITH.

My goodness, Bob, you've never heard of innovation, huh? If everyone had your attitude there world would be stuck somewhere back in the dark ages. You sure gave this fellow a "bah humbug" moment.

Thank goodness for people who want to change things! Else we wouldn't have a polio vaccine, wouldn't have jet airplanes, wouldn't have refrigeration, wouldn't have electricity, wouldn't have telephones, wouldn't have mobile phones, wouldn't have radar, wouldn't have radio, wouldn't have air travel, wouldn't have train travel, wouldn't have wagon travel, wouldn't have a country called the United States, wouldn't have the internal combustion engine as we know it, wouldn't have Federal Express and other overnight services, wouldn't have TV, wouldn't have HDTV, wouldn't have so many cures for so many diseases, wouldn't have GPS, wouldn't have the internet...wouldn't have a lot of things.

But gosh, golly, we'd know all along that everybody before us had dealt with the same things that we're dealing with right now and by gosh, we're just going to have to all deal with the same thing the same way like we've always done!

People who are unhappy with the status quo and who believe they'll be happier with something a little different are this world's innovators and entrepreneurs.

Sure, usually the innovators slog through things that don't work and that everyone has tried before...then they get a little better and little better and little better idea...the next thing you know, they solve a problem that folks like you believe is beyond solving.

I sure hope you don't convey your attitude to your kids or grandkids.


++++++++

Kaa, I don't know why you want to do this--perhaps an outboard is too loud, perhaps its too likely to get stolen, I dunno! But, the little Honda generators last at least a couple years in the marine environment. We've had one onboard our Rawson 30 for two years, use it to power the air compressor when we use the hooka to dive the boat and clean the hull. It still looks and runs like its brand new. We also use it when we go anchor out somewhere for a weekend. Ours is a 2kW, there's one a bit lighter (1.6kW maybe?) that you might use instead. Its very quiet, we use it on the foredeck (don't forget to close the ports so fumes don't end up in the boat) with a shorepower line running back to the plug by the cockpit. We also run an icemaker when we're running the Honda since the air compressor hardly loads it up at all. It uses hardly any fuel. Like say 1/2 gallon in 20 hrs or so? Its amazingly miserly with the fuel. We'll be taking it over to the larger boat when we re-launch. It will be the most cost effective way of generating electricity that we'll have onboard. Our 8kW Onan costs more per kW used and sent to the batteries and our main diesel engine costs even more per kW generated and sent to the batteries. Even when considering that we capturing some of the Onan's waste heat and the main engine waste heat with heat exchangers to heat potable water, the energy we can use from the little portable Honda is more cost effectively transferred to the boat's batteries and electrical appliances.

As an aside, I could swear that the Martins of "Into the Light" and "Iceblink" fame used a portable gas generator on their boat for power. I seem to remember reading in their book about not having shore power during winter in Iceland and using a little generator to generate energy because the days were too short and their solar panels weren't doing them much good. Maybe it was diesel, but I don't think so.

I do assume our little Honda will only make it a few years, but at $850 (online purchase), its a lot cheaper than getting a "real" generator (the Onan cost our wood boat's previous owner about $6K when new and I don't really know what you could get a good little diesel generator for these days), runs cheaper, is quieter, simpler, smaller. For our smaller 30' boat, its the only reasonable solution to electric power at anchor or on the mooring.

My two cents worth :)

[Kaa]

If you absolutely must have 120 VAC, yes, they can be handy, but aren't designed for the marine environment. If left aboard, expect it to turn into a pile of rust in short order.

Maybe, but I'm trailering my boat at the moment. Most of the time it lives on the hard. I am not concerned as much about slow rusting in humid salty air, as about spray and such.

Then there's the gas you'd have to carry and the cost of it. Have you considered how long you'd have to run the generator to charge your batteries? What the generator, batteries, electric motor, etc. etc. etc. will weigh and where you will stow all of them?

Yes, surprisingly enough I have considered it :-) The generators I'm looking at weigh 30-50 lbs and output 1000-2000 watts. They sip fuel and I expect the cost of gas to be miniscule. I also don't expect to need to carry more than a gallon (at most) of fuel with me onboard. A quart, more likely.

Electrical batteries I have onboard already. The electric motor will replace the outboard one and be considerably lighter and smaller.

Look, this is a matter of faith. I know few of the younger generation have any experience with the concept, so I'll explain it. Do you really think that you, all by yourself, apart from all the experienced people in the world, are really going to have a good idea nobody else have ever had before?

Why, yes, I do :D Since you venture into the bilge on occasion, you might have noticed I'm an arrogant bastard :D

I am quite sure that in the case of my particular boat and my particular needs, I'm the most qualified person on Earth to come up with a solution that will fit me.

By the way, electric trolling motors on small sailboats are not rare. If you bother to google the idea -- as I have done -- you will find a number of comments by people who tried this. Some of them were unhappy and went back to regular outboards, others stayed happy.

A whole lot of people have considered the problem you are considering. If there was a better solution than those already available and universally accepted, somebody would be selling it by now. Take it on FAITH.

But of course somebody is selling it :D I'm not about to build a generator myself. Somebody is selling a LOT of electric motors (you can find them at even at WalMart), portable generators, and batteries. I don't see what do you consider so outlandish about the whole idea.

Kaa

[dredbob]

For some good info on this question check out Bob Wise's blog

http://boatbits.blogspot.com/

and scroll down a bit.


Bob

[Roger Cumming]

Having suffered idiots running gas generators on the decks of their power boats in quiet anchorages and mooring fields, I can suggest several additional ways they could meet their end. Energy considerations aside, it is an unneighborly, boorish thing to do.

[redbopeep]

Having suffered idiots running gas generators on the decks of their power boats in quiet anchorages and mooring fields, I can suggest several additional ways they could meet their end. Energy considerations aside, it is an unneighborly, boorish thing to do.

As are the power boats who run their regular generators all night long or even their engines (yes!) all night.

Any generator noise is too much noise for neighboring boats especially in quiet anchorages.

[willmarsh3]

I thought about a generator but I havn't brought myself around to it because of the noise, the gas required (even a Honda 1000), the maintenance, the chore of lugging it around, and the fumes. I really don't like carrying gas on board either. A lot of the generators I looked at only put out 10 amps at 12v dc or some other low fraction of their total output. The rest of the output was 120 v ac.
I have a 20' sailboat with an 80 lb trolling motor and two 12 v deep cycle batteries. The setup is fine for a day's sail. I've done several with this setup.
IIRC you got the 20' Eun Na Mara. I think that would work well with a similar setup to mine. If you are thinking of running the trolling motor and keeping the batteries charged you might want to consider Ample Power's selection of diesel alternators. http://www.amplepower.com These are presumably well optimized for generating power. I have not purchased a unit and don't own stock in the company.
Hope this helps.

[Lew Barrett]

I have a Honda 2K on board. It doesn't see much use but is handy from time to time. It's held up well for about four years with just infrequent oil changes. In my case, its use lies somewhere between infrequent and emergency, but as a rule, once or twice on every extended cruise, it gets called to the party. I have a 1200AH house bank, so I don't call on it except to charge batteries if I'm laying over after a couple of days, at which time I may also heat water with it.
It's very quiet, and unobtrusive. How much it bothers the neighbors is a question I can't answer, but I don't run it at night or unless I've been in the same spot for several days, at which point I count the neighbors as squatters and us as the settlers. I try to be conscientious and have never had a complaint or an ill glance on its account. I started packing it in the old days when I used to make repairs on the cruise. I could run tools with it. Battery powered tools are never charged when you need them on a long voyage, and there's no room on my boat for a kosher marine genie. We're almost all DC, except for what ain't.
Some people don't like gas on a boat and I don't blame them, but I trail an outboard powered dingy (as well as my deck launched row boat) because it's also mighty useful where we go. So we're packing gas anyway. Be careful with that and you'll minimize the dangers. The Honda is the one, and the only one. Lots of people pack them.

[py]

I remember meeting a yacht in papua new guinea. Long term cruising. 30' or so. They had a little genny tied down on the foredeck. kept it there all the time. they said it survived the elements pretty well. Your plan sounds OK t me-you'd want to make sure the exhaust fumes go overboard.

[Lew Barrett]

I see them frequently strapped onto the swimstep, where they can do little harm. Harder on a blow boat without such a thing. In that case one finds the most propitious spot, usually a common sense solution. Like most small gas motors they're just a bit stinky, so nobody is likely to fire on off down below and stay there unless they have malicious intent.

If you cruise with the woman in your life you'll have no problem. They are as sensitive to odd smells on a boat as a canary, and will force a proper resting place for the lump in short order. Run outside they are unlikely to cause a problem as long as you don't run them in your cockpit. You won't run it any longer than is absolutely necessary on a small boat. I guarantee that.

[Kaa]

Let me clarify some stuff. I don't like noise. In fact, one of the main reasons I'm looking at electric motors is that my outboard is a one-cylinder 2-cycle and makes a most ungodly racket.

The point of the generator is not to run lots of electric gizmos at anchorage. The point is to allow me to carry less batteries for the electric motor. For normal use -- that is, motor off the dock into open water and return from open water to the dock -- I don't expect to use the generator at all. It'll just sit there as an insurance that if, say, I'm ten miles away from where I need to be and the wind dies, completely and utterly, I will actually have the capability to get there. Or if it turns out I have to fight a strong current and run the electric at full power. Or some other unpleasantness.

Basically, I want to treat it as a spare battery of very high capacity :-)

Kaa

P.S. I am pretty certain it will live outside in the cockpit and not in the cabin.

[Tylerdurden]

Its not traditional so if you do it you will burn in hell.:D

I am in the process of sharpening the blades on my wind genny.
I will mount it directly above the swim ladder and invite these traditional people on board for drinks.
Of course it also powers my water washdown system.:rolleyes:

[Thad Van Gilder]

Hondas are great but I usually take a cheap $200 chinese special so that if it falls in the water I won't have a coronary.

-Thad

[marshcat]

I use a trolling motor and battery on my small catboat, and it suits my needs well. I don't need the generator based on my usage patterns, but have a question about specifically how you will hook it up. If your batteries run down, will you run a charger off the generator, or some kind of direct connection to the motor? If so, will you immediately have the power you need from the run down batteries? Will the power just sort of pass through from the generator to the charger through the batteries to the motor? I assume the draw from the motor would prohibit you just using a straight ac to dc transformer with some kind of pigtail to attach directly to the motor.

I guess my question is, if you suddenly realize, "oops, my batteries are dead", can you immediately start turning the prop with power from the generator?

Thanks.

[Lew Barrett]

The Honda, for one, has a direct 12 volt output, in addition to the 12 amps or so of ac it supplies. Kaa would have instant power at the pull of a cord. Thad, I understand your concerns, but I'd still get the Honda. It's a terrific package. Conservatively rated, mine looks like new after years aboard, and starts every season without fuss.

[redbopeep]

I guess my question is, if you suddenly realize, "oops, my batteries are dead", can you immediately start turning the prop with power from the generator?

Thanks.

You're talking about running the batteries at zero float. The generator has to have enough charging capacity to run your electric drive motor. So if you have a 3 kW electric drive motor but only a 1 kW generator, you don't have much of a chance unless you can govern it closely. Way back in 1931., our schooner was built with an electric drive (25 kW rated as I recall) and two 10 kW generators and a bank of batteries to drive it. It could run around 6 knots and "zero float" indefinitely with both generators charging the batteries (so 10 kW power per generator or 20 kW total). You have to have enough juice in the batteries to get things started, I would think. Else, if you have a good controller for your electric motor it might work out fine anyway.

That probably wasn't helpful. But, you might want to wander over to the electric vehicle forums where they talk about this type of stuff with more knowledge :)

[Thad Van Gilder]

I made up a special shore power cord just for that and charge the batteries that way.

-Thad

[Lew Barrett]

Me too. Good point Redbopeep. My 2K wil stall out if the big bank is too
depleted. In the event, I fire the main and run it for a few minutes to get over the hump; not an option for Kaa.

[Bob Cleek]

Okay, okay... maybe I was in a bitchy mood yesterday. LOL

I guess what tied my knickers in a knot wasn't my Luddite tendencies, but rather the unrecognized limitations of the recent fad for electric powered boats as a viable alternative to internal combustion engines. The idea of carrying a generator to produce electricity to run a motor to turn a prop is nothing new. I've seen a lot of seventy year old tugs running a couple of big Alco diesel generators to provide power for GE propulsion motors. (Such tugs were designed to serve also as floating generator plants which could be tied alongside a large ship to power her electrical systems while her engines were down.) Indeed, the high RPM internal combustion engine spinning a small prop is an extremely wasteful application of energy for the work of moving a boat it produces. With rising oil based fuel costs, the reliance on this energy inefficient method of marine propulsion is overdue for a rethinking. The cost of petroleum based fuels will eventually be the demise of the widespread recreational use of high-speed planing hulls and small low-drag sailboat props, the former sooner than the latter.

The problem of propelling a boat with machinery was addressed over a century and a half ago, before the "quick and dirty" (and now expensive) solution of high speed IC engines spinning small, low pitched, inefficient props came along. The solution is a properly designed efficient displacement hull coupled with an efficient high torque low speed large pitch propeller. WB a couple of issues back had a story on a fellow who had a nice electric boat built. He did it correctly. He reapplied 150 year old technology by putting his electric power plant in a well-proven steam launch hull.

Unfortunately, torque isn't very efficiently produced by small, low voltage electric motors, so the difference has to be made up in hull design efficiency. Without torque, you can't spin a wheel that really takes an efficient bite out of the water. The best way I've heard it explained, it's like comparing two guys rowing. One, in a fine lined pulling boat with long spoon shaped oars, leans forward, dips his oars, and takes a long strong pull. The other, in an inflatable Avon with short small oars, takes a whole bunch of little short strokes. Which boat is the more efficient?

Once you have eliminated the power loss occasioned by all the inherent inefficiencies in a power system along the way, stuff like friction, prop slippage, hull resistance, and so on, you end up with a pretty simple equation. The amount of fuel energy (BTU's) to produce a given amount of power, or to move a given boat an equal distance, is the same, irrespective of what sort of fuel it might be. Some fuels are "lighter" than others in that they contain higher proportions of carbon to their overall mass. Thus, they are more "efficient" in that it takes less power to carry the "lighter" fuel along with you as you go. (E.g.: Propane = 21,698 BTU/lb. vs. diesel #2 = 20,381 BTU/lb. vs. anthracite coal = 7,603 BTU/lb. vs. shelled corn = 6300 BTU/lb. for you biofuel fans) Comparative costs of various fuels is another factor, perhaps less determinative when considering powering a small boat than would be the space and weight of various fuels. (A gas outboard on a dinghy makes sense because it couldn't carry a steam plant and enough coal to get much of anywhere.)

Nevertheless, when comparing options for powering a boat, you ultimately come up against the same dilema that made all those guys crazy who have been trying to come up with a "perpetual motion machine." There's just no free ride. You have to pick your poison. It's all about compromises and the choices you make.

As a good non-planing sailboat will necessarily have a good displacement hull, it will be most efficiently driven by a high torque low powered large high pitch prop. The problem, obviously, is that dragging a large high pitch prop under sail defeats the whole purpose of an efficient wind-driven sailboat. All the other problems having been long since solved, the "cutting edge" of the frontier for energy efficient practical sail auxilliary power, then, is necessarily folding prop technology. This also was long ago widely studied, but when the then lighter high speed IC engines became cheap and widely available, that line of technological development was abandoned and nobody seems to be making large high pitch folding props anymore.

If you really wanted relative quiet, low cost, and low fuel, space and weight consumption in a propulsion system for a sailboat, I do believe that past research has proven that the way to go is a small relatively large bore low HP - low RPM - high torque internal combustion engine (e.g. the old Acadia "make and break" engine) turning a properly sized large high pitch folding prop. Nothing else has ever come close to matching this arrangement in terms of fuel efficiency, overall powerplant weight, or cost. A good folding prop would solve the drag problem in sailboats. The reason such systems were abandoned in pleasure boats early on was the infatuation with speed. What's the point of speed in a sailboat or any other displacement hull? Once you reach hull speed, that's about it. Regrettably, market forces dictated production of high speed IC engines and nobody makes the old fashioned "gas sippers" anymore.

So, since it was all figured out a long, long time ago, why try to reinvent the wheel with a round-about approach. The direct route is always the shortest: piston to rod to crank to shaft to prop. No need to carry a generator to pump out 120VAC to charge 12VDC batteries to run an electric motor to turn a prop... then again, in a pinch, I guess that approach DOES offer the advantage that you COULD hold the running margarita blender over the side if the batteries failed to take a charge!

[Tylerdurden]

Bob, You leave out a big segment and that is the pleasure or cruising sailor who doesn't have to power except for limited occasions.

I think running my electric out board (which has no drag under sail)
from a battery bank that is mainly charged by wind and solar to be the most efficient.
The other systems with inboard regenerating under sail are in the same league.
We are not all trying to re invent the wheel, just picking a different tread to suit our driving.

[Kaa]

If you really wanted relative quiet, low cost, and low fuel, space and weight consumption in a propulsion system for a sailboat, I do believe that past research has proven that the way to go is a small relatively large bore low HP - low RPM - high torque internal combustion engine (e.g. the old Acadia "make and break" engine) turning a properly sized large high pitch folding prop. Nothing else has ever come close to matching this arrangement in terms of fuel efficiency, overall powerplant weight, or cost. A good folding prop would solve the drag problem in sailboats. The reason such systems were abandoned in pleasure boats early on was the infatuation with speed. What's the point of speed in a sailboat? Once you reach hull speed, that's about it.

So, since it was all figured out a long, long time ago, why try to reinvent the wheel with a round-about approach. The direct route is always the shortest: piston to rod to crank to shaft to prop. No need to carry a generator to pump out 120VAC... then again, in a pinch, I guess you COULD hold the margarita blender over the side if all else failed!

Ah, a thoughtful and reasonable post.

Well, Bob, I would mostly agree with you. And when I am considering an engine for my future 40-footer, I'll make sure to look at good old low-rpm high-torque diesels to turn my large two-blade folding prop :-) However at the moment I happen to own a one-ton 20-foot boat with the power propulsion requirements of 2-3 hp once in a while.

I already have the piston to rod, etc. connection -- it's my outboard. It works and I'm using it. It does have certain disadvantages, though -- it's quite loud, inconvenient to handle, has no reverse. Replacing it with an electric motor would give up some power, but I would gain near silence, light weight, instant-on operation, likely a reverse. The only problem is carrying enough batteries -- not just enough for normal use, but enough to help me get out of nasty situations which, I am sure, will take their opportunities to present themselves. So I'm considering a small gas generator, as I said, as a basically very-high-capacity spare battery. The fact that it's also able to take care of other electrical needs on the boat is a bonus -- if I go camp-cruising for a week, I don't need to worry that I'd run out of juice for my nav lights by the third day...

As usual, it's horses for courses and for small boats your theoretically optimal solution is not necessarily the best.

Kaa

[Bob Cleek]

Yep, the size of the boat is a factor. A small, light, boat can be well suited to an electric trolling motor driven by storage batteries if one accepts the inherent limitations of power and range. If such a boat is used where the electric motor remains capable of overcoming the expected countervailing forces of windage and current and requires power only for the running time/distance that the particular electric system can provide, electric motors powered by storage batteries do work well. Such circumstances, however, seem to be enjoyed only by a lucky few!

Yea, I hear ya, Kaa... Fact is, the old engineering books indicate a 20' one ton displacement hull shouldn't require more than 1 HP, and that's taking into account carrying a steam engine, boiler, water tanks and solid fuel! That modern outboard, gas or electric, is wasting half to two thirds of its power. Not to be too cavalier about it, but a lot of 20' one tonners are using oars these days. (Serrafyn did, for one.) The space saved by forgetting the engine, or batteries and motor, can be better used to fuel the oarsman. I'd expect a pound of beer could yield more BTU's of "boat propulsion" than any fossil fuel, depending on the size of the freighter bearing down on you! LOL Things HAVE improved over the years. LED running lights will consume a whole lot less current than the old incandescent bulbs. You could invest in a pair of oars or one good sweep, plug in LED bulbs, keep the outboard for "special occasions," and save yourself a lot of money and grief... no?

Hey, bottom line, whatever works for you is best for your boat. The best part of owning your own boat is being the captain and doing whatever you damn well please with it.

[Dan McCosh]

Might add that we tried an electric trolling motor on an 8-ft. inflatable last summer, with a single 12V agm deep-cycle battery. It sure beats the folding paddles.

[Kaa]

Yea, I hear ya, Kaa... Fact is, the old engineering books indicate a 20' one ton displacement hull shouldn't require more than 1 HP, and that's taking into account carrying a steam engine, boiler, water tanks and solid fuel!

One-ton displacement is one-ton displacement -- engine, boiler, etc. are part of that one ton. I haven't seen the calculations, but off the top of my head I'm doubtful that 1 hp will get a one-ton boat anywhere close to its hull speed (for a 20' boat, say 18'+ waterline, that would be about 5.5 knots). For leisurely wandering around small lakes sure, 1 hp would be enough. To deal with wind/current/tide in coastal waters, usually with some chop -- not likely.

Not to be too cavalier about it, but a lot of 20' one tonners are using oars these days.

Yeah, well... My freeboard is two feet. I don't have a single athwartship seat and my cockpit is *deep*. I don't think oars are going to work, especially given that usually I'll be the only one capable of rowing. As to a sweep, it's not bad for maneuvering around the dock but if you need to, say, fight current in a channel, it's a lost cause.

I am not all that enthusiastic about bringing more complicated pieces of hardware aboard. I would be happy if I had no need for anything other than a sail and a pair of oars and for small open boats that's a perfectly reasonable proposition. Unfortunately, my boat's size is in-between the point where human power is enough and the point where an in-board engine becomes useful. So -- a search for an acceptable compromise.

Kaa

[Bob Cleek]

A lot of guys using oars in such applications do as the old fishermen used to do. Row facing forward while standing. Somebody, IIRC, actually makes, or once made, oarlocks that locked into the winch handle sockets on top of the cockpit winches for just this purpose. (Seriously, no kidding.) If you are used to seeing wind and current that would render rowing impractical, I can't imagine any electric trolling motor doing better. I'd borrow one to try out before spending bucks on it.

As for the 1 horsepower steam engine, there's no question it would be in the range of hull speed. The design rule of thumb was 1 HP per ton for an efficient displacement hull if you are talking high torque steam engines and high pitch props. The high speed low torque short pitch props really do lose a tremendous amount of power to prop slippage. This came to be ignored when the high speed IC engines made horsepower cheap. It's not as cheap as it used to be. This isn't to say coal and steam engines are the answer. There, the trade off was the weight of the power plant. The half-way point in the compromise is a slow turning high torque IC engine... or so says me.

[J P]

The point of the generator is not to run lots of electric gizmos at anchorage. The point is to allow me to carry less batteries for the electric motor. For normal use -- that is, motor off the dock into open water and return from open water to the dock -- I don't expect to use the generator at all. It'll just sit there as an insurance that if, say, I'm ten miles away from where I need to be and the wind dies, completely and utterly, I will actually have the capability to get there. Or if it turns out I have to fight a strong current and run the electric at full power. Or some other unpleasantness.

Then what about a small 4-stroke outboard with alternator charging and a small solar panel to keep it topped up?

[Tom Robb]

Perhaps I'm missing something here, but if the generator is to use gasoline to run an electric motor, why not just use a gas motor in the first palce?
This seems like a dumb idea to me, but hey - knock yerself out.
The oar/sweep idea sounds nice and quiet, or perhaps a yuloh. I hear tell that litle old chinese ladies can move a fat loaded junk respectably with a yuloh

[Peter Malcolm Jardine]

Try looking at the Torqeedo motors.
and yep, the little honda's are a great unit, and are used widely on smaller boats.

[Kaa]

Perhaps I'm missing something here, but if the generator is to use gasoline to run an electric motor, why not just use a gas motor in the first palce?

Post #25 should provide you with an answer :-)

Kaa

[Kaa]

Then what about a small 4-stroke outboard with alternator charging and a small solar panel to keep it topped up?

Well, I have very limited space into which to fit an outboard. My boat is a double-ender and there's a motor well with just enough space for a Johnson 3.5hp outboard -- that's what I'm using right now. It seems that outboards that can take an alternator start at 5hp, and, say, a 4-stroke 5hp Honda is about $1,800, even if I am able to fit it in, which I'm not sure about at all.

By the way, how much quieter are small 4-stroke outboards compared to 2-stroke? Is it night and day, or just a little bit better?

Kaa

[Gary Bergman]

I have a new five horse four stroke, and it's mucho quiet...and after a bunch of wrenching on our diesel generator, it looks like I'll be hauling our Honda gas generator back onboard...

[Kaa]

A lot of guys using oars in such applications do as the old fishermen used to do. Row facing forward while standing. Somebody, IIRC, actually makes, or once made, oarlocks that locked into the winch handle sockets on top of the cockpit winches for just this purpose. (Seriously, no kidding.)

Yeah, I know what you're talking about. However I do have a deep cockpit :-) By my quick estimate, if I'm standing in the cockpit, the distance from my chest to the water level, passing just above the sheer line, is about 10 feet. That means 12-foot oars. There is also a coaming which the oars will have to clear, so, say, 14-foot oars.

Theoretically doable, if I have two strong rowers and want to pretend I'm a micro-trireme or something :-) but in practice it's not viable.

Kaa

[Lew Barrett]

The cockpit would, by the sound of it, be the very worst place to locate your new generator, by the way.

[StevenBauer]

Seems Minna uses oars for propulsion:

http://www.duckflatwoodenboats.com/designers/oughtred/eunmara4.jpg

:D


Steven

[Kaa]

Seems Minna uses oars for propulsion

Hmm... interesting :-)

Looks more like a paddle to me, though I don't know why it's so thick.

Too short to be a yuloh, and too short to be an oar on a Eun Mara, too, to tell the truth. Oh, and there's another picture of Minna on that day showing its starboard and there is nothing there on the sidedeck. So -- a single paddle for maneuvering around a dock, most likely.

Kaa

[mcdenny]

There was a question way back there somewhere about what to do if (when?) the batteries died.

If you had a 12v motor you could run it off the generator's 10 amp 12v output. That's only 20 watts, about 0.16 hp, not much.

A better option is to plug the battery charger into the 120v ac output. Now you get as much power as the charger can put out, up to the limit of the genset (1.6 kw for the 2k model).

If the only load on the generator is the charger there is no point in getting a bigger generator that it can load. The charger specs will list the input power. The smallest Honda EU1000 would be plenty for your application, puts out 900 watts continuous and only weighs 29 lbs.

[J P]

By the way, how much quieter are small 4-stroke outboards compared to 2-stroke? Is it night and day, or just a little bit better?

Maybe not “night and day” but WAY more tolerable to my ear.

Do motor wells tend to muffle sound or resonate?

[Ron Williamson]

At idle, the noise you hear is the pisswater.
R