On 10/11/2020 12:10 AM, Rupert Boleyn wrote:

> One tonne of liquid hydrogen takes up forteen cubic metres of volume.
> Nine tonnes of water include one tonne of hydrogen, and has a volume of
> nine cubic metres. You get about 1.55 times as much hydrogen into the
> same volume, but the mass per quantity of hydrogen is nine times as
> great. In CT, MgT and a number of other rule sets spaceships care about
> volume, not mass, so water is useful if the referee is willing to go
> with it. The downside is that it's very definitely unrefined fuel, even
> if the ref is generous (I simply disallow using water as jump fuel), and
> carrying it and then refining it requires a refinery/purifier, time, and
> a tank to hold the water as well as one to hold fuel.

On the gripping hand, water is /much/ easier to handle than lHyd, as it
can quite literally be stored at room temperature, is not explosive when
allowed to warm up and mix with air, etc etc.

--
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Kelly St. Clair
xxxxxx@efn.org