BIT: A Tale of Two... Experimental boats?

[Jericho941]

A friend of mine has been toying with the idea of building an almost entirely self-sufficiently fueled boat some day. This is all academic, since it'd be a long time before he could afford to try WECSOB, but here's the gist:

The boat runs on a hydrogen engine and incorporates an electrolysis system to gain more hydrogen. In order to get around the problem of not being able to get enough energy from the hydrogen alone, he'd power the cracker with large solar panels in addition to electricity generated from engine power.

I think this requires either impractically large solar panels, or more efficient ones than actually exist. I don't know much about boat engines, but I do know that compared to car engines, they suck up a lot of fuel to get from A to B. I don't think it'd be possible to crack enough hydrogen run on solar panels to power a blue water-capable hydrogen vessel. But I could be wrong.

One of his ideas included recycling the exhaust, running it through keel coolers to provide access to a source of clean water for cracking. I'm not sure whether it matters, but it got me thinking about nuclear reactors, and further back, steam engines.

I started to wonder whether there might be any point to a solar powered system that heats water rather than directly drives an electric motor. Would that be less efficient? Maybe you couldn't pull it off in a large boat, but a small one powered by solar energy, if at all possible, would offer the same independence from refueling without having a complex and dangerous cracking/propulsion system.

Thoughts?

Preemption: Sails are right out.

[Denis]

I think the problem with the solar-powered hydrolysis plan is that, once you have the energy in electrical form from your solar panels, you'd be better off just using it to power a conventional electric-motor-driven propeller. A number of solar-powered boats already do this. I have actually been on a working solar-powered merchant vessels - a sightseeing boat on a lake in Germany.

I'd have to look up the exact numbers, but I suspect that the energy efficiency of good electric motors it at least as good as, if not better than, that of hydrogen-fuel motors in terms of electricty in versus motive power out.

Add to that the fact that your boat is going to need batteries to store the electrical power (at nighttime, for example), and you're already 2/3 of the way towards building a conventional electric-motor solar-powered boat. Hydrogen storage is bulky and heavy, and why bother, if you already have batteries anyway?

[Aglifter]

Yeah... you're pretty much talking about a sailboat but one w. the power dedicated to generating fuel -- frankly you'll need something better than hydrogen -- too hard to store.

[SeekHer]

Speaking of experimental boats I submit for your viewing the J Ruiter Pod Racer...sort of looks like a Citron body with feet...

[drice]

Speaking of experimental boats I submit for your viewing the J Ruiter Pod Racer...sort of looks like a Citron body with feet...

Yep. Ugly.

[mekender]

how much electricity can be generated based on movement and tidal forces?

similar to:

http://en.wikipedia.org/wiki/Mechanical ... flashlight

[Alcibiades]

Preemption: Sails are right out.

Loophole: Generate the electricity with a wind turbine. (Or solar cells plus wind turbine, either way.)

[FastRope71]

A closed loop hydrogen system powering an efficient electric motor could work reasonably well. Light weight + shallow draft = less water displacement = less energy required to move it.

Anther efficiency enhacing device would be a clone of the flipper prop used in a canoe builder's product. Instead of a rotating blade, the drive is a pair of flexible flippers underneath connected to a bicycle type pedal. One average guy manages to hod of two professional paddlers in a tug of war.

You don't need to store large amounts of hydrogen for long periods, if it is constantly making hydrogen. That which gets out between the molecules of the holding tank just get replaced. One might want to consider some sort of back up propulsion unit for running after dark when the hydrogen gets used up.

I found it the Hobie Mirage drive.