On Tue, 14 Jun 2011 14:33:42 -0700 (PDT), Frogwatch
wrote:

On Jun 14, 5:25*pm, Boating All Out wrote:
In article 42a60c43-00c3-450a-9e7a-
,
says...



"neutral Buoyancy" simply means the same average density as water.
Putting the object under water will still allow it to release gas
which will rise to the surface. *In spite of the propane being higher
density than air, some will diffuse to higher than the transom and
then will sink into the bilge, all basic physics. *The hazard to my
boat from this canister was orders of magnitude greater than the
hazard to any other boat from an empty canister.

Stop digging. *It's laughable to say a small cannister of slowly leaking
propane bobbing in the sea will blow up your boat.
A mere foot away from the canister the gas will be too dilute to
combust.
A fart is orders of magnitude more likely to ignite than any measure of
gas that gets to your bilge.
You have no certitude here.
Just nav hazard creation.

You do not have much experience with this sort of thing it seems. Do
NOT try it. Combustibility is not a simple matter of concentration
because 100% propane will not ignite whereas if you dilute it, the
probability of ignition goes waaaaay up. At higher values it goes
down again. Being heavier than air is the major danger to boats
because it settles to the lowest point where it can reach a higher
density than it would be at deck height.
The same is true to a lesser degree of gasoline vapors. Ever seen
someone throw a lit cigarette into a bucket of gas, nothing happens
(nearly 100% concentration) whereas if he held the cig above the
container...............This is why boats have bilge blowers.

You're nuts. There's no way that small amount of propane was a hazard
if it was in the water, down current and bubbling. Maybe 5 minutes
then it would be empty.