bruce wrote:
Hi
I'm looking at $220 for a 9kg alloy lpg gas cylinder or $60 for one of
steel.

How long is a steel one likely to last?

cheers
bruce



How willing are you to meticulously touch up any paint chips? Rust
is a steel tank's biggest enemy.

Presuming that 10 year old steel tanks are not worth refurbishing,
as required by regulation, that means tanks cost about 3 bucks a
year. The fuel cost will likely far outweigh the storage cost if
you use much, so this part of the discussion is really a waste of
effort.

You would need to keep your alloy tank for about 70 years to
approach break even, not counting testing and refurbishing every
decade, which would seem to make it unlikely to ever occur.

Alloy tanks that old likely would have been sold with the boat by
your heirs long before you derive any financial benefit from them.

Having such fancy tanks would be bait for thieves, who might think
you simpleminded for using them, and an easy mark. Anything
outstanding like that would be the same bait. Or, they might think
you must be a military bigwig, or astronaut with inside scrounge
connections and they might wonder what other classy booty you have
hidden below decks.

Better a shabby looking poor man's boat, for security reasons, with
bad paint, a broken something on display, painted on oily drip
marks, dark tinted windows, hidden alarms, and a nasty dog, might be
better camouflage and protection for your high end interior.
Sparking wires hanging into the water a la Captain Nemo's Nautilus
might also scare away or electrocute potential trespassers and
thieves. "Monster" Simulated sparking wire detractory security
systems can be obtained, but they, and their expense, only make
sense in extreme circumstances.

Depending on how you value your time spent touching up paint chips,
the equation could swing toward alloy tanks at possibly 100 dollars
an hour and many chips in the paint. You will have to do that cost
benefit analysis yourself, since alloy tanks have their own
maintenance requirements, dependent on the alloy.

Terry K -Proprietary Stealthy Wealth Security Systems Consultations- ;-)