Lets look at the safety of both suggestions.

1) Nitrogen liquid will boil to gas. The gas is an asphyxiate. Many people
have died from nitrogen. Air contains 21.5% O2 mostly the rest is N2. If
you breath pure N2 the first breath you pass out and the second breath brain
damage and the third death. Think about passing out when reaching for
something in the ice chest. If you fall in your dead; if you fall out you
will probably be ok. The next day you will be ripping out your N2 system.
A closed boat can accumulate N2 which will displace air. Maybe get you in
your sleep or when you go down for a cold one.

2) CO2 is heaver then air and would accumulate in the low parts of the boat.
Same issue as with N2 but it would at least give you some warning signs.

Whats wrong with a little water from melting ice. You are on a boat
right???





"Jeff" wrote in message
. ..
Glenn - Water ice only holds .5 (or less) BTU/lb-degree, so cooling it
down to zero is only adding another 15 BTU per pound for a total of 159
BTU.

Glenn Ashmore wrote:
I found the best price on ebay. There is a guy on there that sells it.
Apparently pretty reliable because I have suggested him to several
people, all of whom have been very happy with his shipping. The proper
term is "Techni Ice" . In my testing the Techni ice only lasted about
30% longer than water ice but the temperature averaged about 15F lower.
Frozen to 0F it absorbs about 152 BTU's per pound compared to 176 BTU per
pound of water ice but water ice only absorbs 1 BTU per pound until it
gets to 32F and starts to melt. The gel in Techni Ice starts melting at
a lot lower temperature and is pretty well all melted by the time it
reaches 32F. Apparently it also will absorb more than 1BTU/pound when it
is frozen to very low temperatures although I don't fully understand the
physics yet.

The other part of the performance is the Coleman Ultimate Extreme cooler.
It is exactly 1" under the maximum size you can check on an airline and
is about the best insulated mass produced cooler on the market. The
"marine" version cost about $10 more than the regular model but the only
real difference is that it is all white and has an extra set of rope
handles which can handle the rough treatment of baggage handlers. The 50
quart wheeled model that Wal-Mart carries is nothing like as good.


I keep 5 or 6 sheets in the freezer and just turn the freezer side down
to the lowest setting about 4 days before a trip. All the food goes in
Ziploc bags in the freezer for 3 or 4 days to get it as cold as possible
and I pack the cooler completely full. A towel on the bottom adds a
little insulation to the coldest area and any voids are filled with
towels, extra bathing suits, etc.