Dry Ice in the Ice Box ?

[Connemara]

Sarafina:

I bought three sheets of the stuff at the Auckland Boat Show in March and am just now testing them out.

Unfortunately it has been cold here in Toronto -- no more than about 12 C since launch, so it's hard to gauge how well they perform.

They seem to stay frozen for about two days and cold for another day. Then you refreeze them, which takes a day.

But when it does warm up -- bound to, sooner or later -- they may last less long.

That's longer than a bag of ice in my mostly uninsulated icebox. And I don't have to drain the box, which is a bonus.

The other trick someone mentioned -- frozen water in plastic bottles -- also works very well. I suspect I will be using come combination this summer.

Connemara

[sarafina]

the frozen water is a good plan as well. I use odwalla bottles. nice and square with good screw on tops. Freeze them standing up w/o the lid. They keep for a coupla days. But they are bulky. The square shape helps with the space usage.

[Jerry Woodward]

Originally Posted by Amgine

................I was acutely aware of smell of CO2 in the boat, and it was noticeably stronger toward the cabin sole, so we slept in the cockpit several nights and never closed up the cabin or shut off the fans at night - which resulted in more engine running to keep the batteries topped up.................If dry ice were readily available in my cruising range - which it isn't - I'd consider getting a much-smaller amount of it once a week or so instead of ice to test if it was the sheer quantity which caused the strong smell of CO2.

CO2 (and dry ice) is colorless and odorless. If you "smell" CO2 you are smelling a contaminant of production. This probably shouldn't be used for food storage. There are different grades of dry ice and you want to make sure you get food grade, or high purity.

Jerry

[Amgine]

That lovely 'scent' when you crack open a soda pop is CO2; most people can smell it. I lived in it for a week, could detect varying levels of the smell, and watched dogs trot down the dock and swerve to avoid our side of it.

But sure, CO2 must be odorless for you.

[marshmat]

We used to have carbon prepregs shipped with dry ice, to keep them from thawing as they sat at Customs waiting for the right papers to be passed around. With three or four inches of light styrofoam, a box of about six cubic feet could be kept cold for a couple of weeks.

Eventually, a few of the guys decided to get rid of some of the dry ice we had been stockpiling in our shop freezers.... turns out it's OK to chill beer on it, but not OK to put it IN the beer.

What you're really looking for in an icebox is high volumetric heat capacity- ie, something that can absorb a lot of heat, relative to its volume, for a given temperature rise. The enormous amount of energy needed for water's phase change at 0 C makes it surprisingly good for this purpose. Dry ice is not as good as it might appear in this regard. But it doesn't make a wet mess of everything, an important factor when shipping cold items.

[GordMay]

Originally Posted by Amgine

That lovely 'scent' when you crack open a soda pop is CO2; most people can smell it ...

At low concentrations, Carbon Dioxide is odourless. At higher concentrations it has a (faint) sharp, acidic odour, and a sour taste.

[cal40john]

Originally Posted by stark

I wouldn't worry so much about dry ice.

A 30' boat has close to 60 kg of air inside the cabin. If you have 1 or 2 kg of dry ice that takes several days to sublimate, your not going to notice a difference. Anyhow, typical person exhales on the order of a kilogram of CO2 per day.

Not that I believe that using dry ice is a concern since this is old news and has been used for a long time, but the post after yours says he used 8 lbs, and I found on the web that Krogers sells dry ice in 9 lb blocks, that's 18 to 20 kgs. I think folks are using more than a kilo or so.

John

[Therapy]

Originally Posted by cal40john

and I found on the web that Krogers sells dry ice in 9 lb blocks, that's 18 to 20 kgs.
John

20kgs is 44.09245 lbs.

[cal40john]

Originally Posted by Therapy

20kgs is 44.09245 lbs.

OOps, I know it's 2.2 lb per kilo, screwed up and multiplied instead of divided, so 4 kilos, not as significant a fraction of boat volume as I thought.

Approximations were due to whether you got an 8 or 9 lb block of dry ice.

John

[anjinsan]

Used it many times...$1.00 per pound...5 lbs top..5 on the bottom..what it really does is keep you ice frozen. One trip to Catalina...after few hours on our pin, we heard a very high pitched sound.....seemed to be coming from under the boat. Seems the dry ice fell out of its insulating paper and was touching the fiberglass ice box bottom and "Chattering" throw a piece of dry ice on a dry surface and it starts to jump...the warmer the surface..the more it jumps about...
Don't fear this stuff..it works well...10 lbs lastes us a week end...all cold..all good.

[Gracias]

but the strangest thing happened: after a couple days in the ice box they became carbonated.

Yup. I drove an ice cream truck one summer while I was in college (made more money that summer than any other, btw) and found out about the carbonation thing.

During the day, while I was driving my route, the freezer was packed with dry ice blocks wrapped in newspaper (small 1 lb blocks -- a bunch of them individually wrapped and placed throughout the freezer). At night, I'd plug the freezer box in (AC) at home.

I soon discovered that if I left the remaining dry ice in the freezer overnight, the next day all the ice cream would be carbonated and fizzy. Some of it actually tasted great that way, but people who didn't expect it were mostly not impressed.

I wouldn't use it on my boat because anything permeable WILL get fizzy.

(But, on the other hand, it's great fun to put a little chip of dry ice in a cup of water and wow all the kids.)

Rebecca

[jrogers]

A marina buddy related the folowing story-
As they were crossing from Mexico to the Marquesas there was a tug stationed offshore, many days out, offering fuel and ice for sale. They would buy fingertip-sized slivers of dry ice and wrap them in tin foil. Drop them in an aluminum can filled with water and it would instantly freeze keeping the ice box cold. A little went a long way.
John

[Gracias]

it would instantly freeze keeping the ice box cold.it would instantly freeze keeping the ice box cold.

Hmm, that's interesting! I'm going to try that just to see. I guess the ice created this way would stop the fizz; wonder what part the foil plays. Thanks, John.

What I REALLY want to play with is that stuff from Australia ...

Rebecca