alternative auxiliary propulsion

Hi all,

What a compromise!

I wish boats did not have to have engines. Yet how to get along without them, especially if you want some mod cons etc.

Using Skene, I need some 50 to 60 HP.

Has anybody any thought on alternative methods of auxiliary propulsion?

I like the idea of pure electric drives, but have yet to do the cost benefit analysis. What about a diesel-electic system. Is this a good? What about an outboard?

I wonder whether anybody has any thoughts on this conundrum.

dionysis.

 

Think about the fuel cell, and about the fact, that most of the yachst and pleasure boats stay at the harbour for the hole week. If you manage to integrate solar panels in to the design of all these boats in the future, they could produce enough H2 for the trip on the weekend.
Then you have the all electric ship, wich will also produce the enegie for it self.
You could also burn the H2 in a modificated normal diesel engine. The first option is smarter in my opinion but more expensive.

see you

Max

 

max

thanks Max. I will checkout fuel cell technology. I like the idea too.

cheers, dionysis

 

Right now, fuel cells are energy storage devices (like a battery), not energy production devices (like an engine or genset) - at least for hydrogen/air fuel cells. A gasoline/air or even a natural gas/air fuel cell would be a different matter. Of course, a hydrogen/oxygen fuel cell wouldn't be competitive at all, due to the need to store both gasses.

The topic of alternative proupulsion comes up periodically on the Multihulls mailing list. People who have run the numbers come up with a lighter aux propulsion system by using conventional diesel installations. Electric propulsion might be a competive option, depending on the requirements.

One reason electric propulsion comes out heavy is the batteries required. But if you took a total systems view and the batteries were already required anyway, then electric propulsion might be the optimum choice. Say you have high demand for house current and propulsion is not the major energy user. This might correspond to a boat that is sailed a lot in the trades, but has all the creature comforts. In that case, a diesel genset plus generous battery bank would take care of the house needs, and aux propulsion would be mainly used getting in and out of harbor. The genset would be more efficient than running a diesel propulsion engine to supply house needs.

But maybe it wouldn't be a good choice for a charter boat that spends a lot of time motoring in order to get to where it's going because of time constraints. Likewise, if a boat has to motor a long distance because the winds are light or if it has to buck fast currents, then it may need a more robust propulsion capability. And of course, for a racer it would be too heavy.

I think you'd have to take a comprehensive look at your requirements to see if it makes sense.

 

Tom

Another sensible reply.

Just wanting get in and out of tight corners, with some reasonable creature comforts, points toward a genset as backup. This is realistic.

I like the idea of minimal impact on the environment too, and minimal impact on the hull.

All I got to do then, is figure out a way of hanging a propeller off the end of the boat, like an outboard.

Cheers dionysis.

And thanks again Tom.

 

It doesn't take much thrust to move a multihull, and I've often wondered whether a trolling motor in the outboard hulls would be an acceptable auxilliary. Two motors would give good maneuverability, too, and be easily controlled from the cockpit.

The limiting cases tend to be if you need to motor into a stiff wind, which could happen coming and going from the marina, and speed to buck a current when transiting a confined area. Range is another issue. The ability to motor a few hundred miles would be a reasonable requirement for an offshore cruiser.

A belts-and-suspenders combination would be to have an IC engine for propulsion, a genset, and one or two small electric motors. When possible, you could use the electric propulsion and the genset might be desired for house loads alone. But if you really need to motor, you'd have the capability, with the electrics used as maneuvering thrusters. It also gives you a backup for everything.

 

classic compromise

Yes trolling motors are a good idea for a multi.

Hmm...You mean belts-and-suspenders-plus top hat.

For the 20 ton monohull I have in mind, I like the idea of a genset, batteries and either an electric or hydraulic drive of some kind.

But I have a fair bit of research to do yet it seems.

cheers dionysis

 

Fuel Cell technology

You might have a look at this technology...real promising to make fuel cells a viable everyday energy source.

Hydrogen on Demand™
Millennium Cell's proprietary Hydrogen on Demand™ fuel system safely generates pure hydrogen from environmentally friendly raw materials. The hydrogen is stored on-board at ambient conditions in a liquid fuel - an aqueous (water-based) solution of sodium borohydride, NaBH4. Sodium borohydride is made from borax, a material that is found in substantial natural reserves globally, with a particularly large supply in the U.S. The process supplies pure hydrogen for energy applications without the need (and associated energy penalties) for compression or liquefaction. Hydrogen produced by this system can be used for a variety of applications, addressing a wide range of power requirements.

http://www.millenniumcell.com/about/index.html

I wish our goverment would cut out at least one F-22 fighter aircraft (which we really don't need in any nearterm future), and put that money and brain power effort behind a technology such as this. And think about what this type of energy technology could mean for our economy as well as that of the world. I happened to have visited the Air & Space museum yesterday and caught a video speech by John Kennedy to the US Congress urging our concerted commitment to a voyage to the moon. What a great period of time for the USA. Its time for the USA to lead again, and I don't mean in weapons building, proliferation of same, and pre-emptive wars.

 

There will be no shortage of air driven motors on the market once governments figure out a way to tax air. In the meantime, no government is serious about developing a carbon based fuel alternative while billions can be easily obtained from carbon fuel tarrifs and taxes. I'm very interested in alternative energy because the motor in my 44 footer is a 120hp two stroke that consumes a quart a mile under load. As a pensioner on US $170 a week, paying out $1 per mile hurts a little. I saw a diesel hydraulic on a 50 foot cat that had two screws driven from the same motor rated at about 50hp. Another angle may be a variable pitch prop. A friend has a fifty foot schooner with a 50hp two cylinder donk with a variable pitch prop. His yacht has yet to be launched but the guy who talked him into the package had a larger boat with the same unit. It worked fine.

 

Note that the efficiency of the propeller in a sailboat has to be limited because of the possible drag while sailing. This is why a lot of sailboats need more power than one might think. However, if the prop can be retracted, it can be larger and turn slower (though small outboards, for market and cost reasons generally run fast). One approach to retracting sail boat props is hydraulics, and a Seattle area hydraluics rep had a home made hydraulic outboard, with a Kort nozzle, powerd by a PTO on his gen. Something like that is relatively easily makeable. An electric outboard is another possibility, again with a slow turning, big prop.

Another possibility is a low horsepower Stirling (see www.sesusa.org) outboard, and it might be feasible, though one would have to be an amateur machinist, and the big fun would be making it. At least this would be quieter and be able to run on odd fuels.

However, the bottom line is to look at the efficiency of the propeller for possible significant improvements.

 

Retractable Propeller (and drive)

I wonder if this 'Seattle rep' had previously had any contact with the Hungarian gentleman I mention on my website with reference to hydraulic drives. This gentleman was from that very region and had spent considerable time and testing at various facilities to developing bow thruster devices. I felt his unique motor had many additional posibilities, and certainly a retractable possibility.

I also mention belt drives in this site reference
These type of drives eliminate the 90 degree geared shafts so larger HP diesel power can be transmitted, and the rotation centers might well allow for retractability. I don't show any retractable sketches on the website, but I've drawn a few.

I was talking fiber-belt drives that are seeing a lot of industrial application now. Somewhat recently PYI has pursued a similar idea (although not retractable at this moment) utilizing a 'Morris' steel chain belt. The most popular utilization of these 'belts' were in the connection of the engine and the transmission in the Oldsmobile Tornado. I think they also saw some application on old industrial pumps used on fire trucks?