the single most important question for any alternate-fuel ships?

[Ike]

Right on PortTacker. The solution has been around since the beginning of time and people who like to go fast just fail to see it. The wind. Ships sailed everywhere for centuries without engines of anykind.

But to answer the first question, the answer is complex. to know how far, you need to know w lot of things. How big the boat, how fast, ocean or lakes and streams, and so on. At the Office of Boating Safety we always used the rule of thirds. A third for going out, a third for coming back, a third in reserve. (sh.. happens) How much is dependent on how far you are going and how fast, and how big the boat is, and to some extent the tpye of boat (displacement or planing)

[TeddyDiver]

Originally Posted by Ike

At the Office of Boating Safety we always used the rule of thirds. A third for going out, a third for coming back, a third in reserve.

Is this rule met with three reefs in the main

A trireme

Or a trimaran

[robherc]

Hmmm... I guess if I were going to bottom-up design a MOTORIZED system where NOT using fossil fuels was paramount, and speed was "highly-negotiable" I'd probably try something like the following:

Electric motors with small-moderate battery banks;
Strikeable (i.e. put 'em up when you're not moving, take 'em down when you are) wind-turbines for primary electrical generation/battery charging;
A small E85 (or biodiesel, or any other renewable, combustible, fuel) fired steam-turbine generator as a standby power source.

That way you could have unlimited range thanks to the wind turbines, zero emissions during normal conditions, and the flexibility to burn alcohol fuels (or fossil fuels in a pinch) to generate backup electric using a highly-efficient steam turbine (and there's plenty of cool seawater around to make steam out of)! I think that would be the best system you could find from a price & efficiency standpoint...except, of course, for just sailing in the first place

[TeddyDiver]

Totally independent:
Windturbine-electrolysis-hydrogen tanks-fuelcells-electric motor.

[robherc]

That would work too Teddy, but to my knowledge, batteries are still lower-entropy than hydrogen harvest via electrolysis...and less of a pain where storage is concerned (and they're less likely to go BOOM if mis-treated). Still a viable process, just that I think using batteries would be more efficient & slightly safer.

[Tcubed]

Now picture this

<Windturbine-electrolysis-hydrogen tanks> --- At the ports

And,

<hydrogen tanks-fuelcells-electric motor.> --- On the boats.

Then we'de have gone full circle and be using the wind for maritime transport but without the big crews and flexible timetables that go with the usual sails.

[FAST FRED]

Since the chance of a crash is low (which would keep the lawyers at bay) the use of a modern flywheel carbon fiber, Vacum case , magnetic bearings with ability to install/remove energy at high rates still has the biggest power per pound of other choices.

Not very sexy , doesn't get free "development" $$$ from the gov , but it does work.

FF

[Tcubed]

I thought flywheel energy storage technology had pretty big engineering problems with gyroscopic forces when installed in a gyrating system, such as a ship.

[robherc]

Originally Posted by Tcubed

Now picture this

<Windturbine-electrolysis-hydrogen tanks> --- At the ports

And,

<hydrogen tanks-fuelcells-electric motor.> --- On the boats.

Then we'de have gone full circle and be using the wind for maritime transport but without the big crews and flexible timetables that go with the usual sails.

T^3
Now THAT would probably be workable...using the hydrogen as simply a more energy-dense storage device than batteries. Still, how are we going to convince the ports to install H2 fueling facilities? Or are you planning on buying/leasing a small amount of space near each port to build your own turbine+electrolysis+storage+filling station?

[TeddyDiver]

Originally Posted by robherc

Or are you planning on buying/leasing a small amount of space near each port to build your own

What a perfect time to throw some $500 billion in the infrasructure of some environmentally healthy project..... 35 years gone after oil crisis it might be the time...

[Tcubed]

I've come to the conclusion that out of all the renewable energy systems it is no doubt one of the best. There is in fact no 'probably' in its feasibility, its only a matter of implementing it.

12 500 000 $ get wasted on nurturing the resentment and hate entire countries in the middle east feel for the US ........ Every hour.

The technology to create infrastructure for completely renewable energy systems already exists and would cost far less than this. It truly is one of the great tragedies of our time.

The 'wind turbine' could just as easily be solar or tidal, depending on what is the most cost effective for a given location. I am still trying to think of a port in the world which has neither abundant wind, sun , nor tides. They must be fairly rare.

Once we are using 100% renewable energy our entire geo-econopolitical landscape would change from one of scarcity to one of abundance. This is a very profound change that does not benefit the present system. In fact, not until the present system is destroyed and a new one created will we see this new logical structure wholeheartedly embraced. Power seeks its own self preservation, thus always resists any fundamental change that threatens its continuation.

That is why nothing significant has yet been done about it despite the absurdity of clinging to unsustainable ways of sustaining society. Nor will they, until it destroys itself due to the very nature of it.

Therefore it is up to us to spread true knowledge and act on it. There is a lot of power in a commonly held thought across hundreds of millions of people. Like an old friend of mine used to tell me; <You deserve what you tolerate>

[milflower120']

im planning on building a sail boat for a trip im taking. im sailing to bora bora from the united states out of california with a group of 8 and i need to know the minimum length i need to make the boat in order to reach my destination because i know there are some big waves in the pacific.

[Tcubed]

WTF? I think you're in the wrong thread , mate.

[robherc]

milflower120', may I suggest you check out one of the "stability" or "seaworthiness" threads? That should be what you're needing bud.

[ijason]

the only problem i see with hydrogen storage - and believe me, i love the idea of electrolysis via solar/wind - is that it takes a whole heap of energy to compress hydrogen down to a liquid state, and i'm thinking for any viable amount of distance you'd need a large store of liquid hydrogen.

i'm not too familiar with fuel-cells, but i do recall that they use a petro-chemical that is charged with hydrogen, and then the hydrogen is used as it is released... does anyone know if it's possible to re-charge a fuel-cell directly with raw hydrogen? or do you recharge one by replacing the petro with new? it seems that if you could directly charge a fuel-cell with freshly cracked hydrogen (via solar panels and sea-water) then you could much more safely store large amounts of it, and avoid the energy-hungry process of compressing it down to a liquid.

that was actually kind of the point of my original question. it translates directly into any renewable energy. how much battery do you need to motor for the minimum recommended range, and then how long can you reasonably spend parked there refilling your storage. the question applies to hydrogen and fuel-cells as well. it seems to me, though, that you could carry vastly greater energy stores in fuel-cells, than you could in batteries. yes?