Anyone using dry ice to cool for several days??????

[kloudie1]

Side Note.. recently found a supply of block ice near the boat. The guy is a supplier of ice to the snowball stands and it comes in blocks that are the shape of a half gallon milk box, only 50% longer for 6 pounds. Apparently, that is a standard size for the shaving machines. It stacks and layers well. He keeps it in a freezer at -10F so I don't lose any driving the 20 minutes to the slip..

 

[Weasel]

Dry Ice

Solid Co2 does not melt, evaporate, or disappear, it sublimes. And when it sublimes it returns to the gaseous state. Co2 is 2.5 X heavier than air, so it will collect in your bilge, but it would take a lot to aphixiate you as you lie unaware in your bunk. I used Dry Ice a lot on my boat, as a cryogenic engineer I could gets tons of the stuff. Take the dry Ice and wrap it in a terry cloth towel and put it on the bottom of your ice box. Rest it on a couple of bottle caps so it does not block your drain.
Put your frozen stuff on top of the towel. Then Insulate with another towel and put your drinks and non frozen stuff in the ice box. A side benefit is that Co2 inhibits the growth of salmonella bugs, so your food will stay fresher longer.
Tried to make vodka ice cubes one time w/ liquid Nitrogen, worked ok except they kept freezing the tonic!

 

[David in Sandusky]

Risk...

So, if we have dry ice in the cabin of the boat, and we have one of those nights when the wind just disappears, and the water is dead flat at sunrise, could the CO2 gas fill the cabin over our bunks?

How will we know if this happens? Oh, we'll be dead!

Our boats have excellent safety systems for the much much lower risks of capsize, striking a rock, or man-over-board. Ice plus frozen meats and soups work for us on Lady Lillie. But if we were going to use dry ice in the cabin, I would want some serious understanding of the risks, and appropriate, reliable ventilation and alarm systems.

 

[Buck420]

Dave,

When I used to use dry ice in my boat's "ice" box, I found that a one pound block of dry ice takes about 5-6 days to completely sublime in a reasonably well insulated (boat) refrigerator. That's < 3oz of CO2 diffusing into a typical boat every 24 hrs. (Less than 1-2 oz overnight).
Considering that:

An adult at rest breathes 16 respiration per minute - approximately 5 m3/h (lungs volume 4 - 6 liter). With harder work the rate is 3 to 6 times more (15 - 30 m3/h).
The average composition of exhaled air is

• Oxygen 16.5%
• Carbon dioxide 4.0%
• Nitrogen and Argon 79.5%

The quantity of carbon dioxide exhaled in 24 hrs is about 1 kg.

Since 1oz = ~28grams (.028kg), and since two people on a typical sail boat exhale approx .67kg of CO2 overnight, then (if my math is correct)
two people (overnight) exhale approx 24 times as much CO2 as is subliming from the one pound block of dry ice in their refrigator.
If you are worried about becomming aphixiated from CO2 in your sleep, you would be far better to get rid of your sleeping partner than the dry ice in your refrig.

I'd be far more worried about "Weasel's" vodka ice cubes freezing my vodka tonic than being aphixiated from my subliming dry ice.
(Besides, my dry ice makes the ice cubes i DO use in my vodka tonics bubble and effervese.... which is all the more reason to have the stuff in my "ice" box.)

 

[BobM]

Hmmm...so 16 respirations per minute x 60min/hr x 24hr/day = 23,040 resp per day x 5L lung vol = 115,200 L or air per day x 0.04 (4% CO2 in air) = 4,608L of CO2 / 22.4L/mol (ideally) = 205.71 moles of CO2 x 44 g/mol =~9kg of CO2 per person per day per my calculations.

In any case, other factors include the amount of ventilation, the quantity of dry ice, its surface area and the ambient temperature (which should be very low inside the ice box). Plus, if you are using dry ice, chances are it is because it is hot out and the boat is not buttoned up.

I really wouldn't worry about it too much. If it was getting to be a problem, the inside of the boat would look like the movie "The Fog" first and it would get mighty chilly inside. We used to dump pounds of dry ice in our lab sink and turn on the hot water just for fun. The cold fog use to fill the sink and pour out onto the floor, but it dissipated rapidly. The only thing that would make me hesitate is freezer burn. Were I to use it, I'd put it at the bottom of the box and then put a layer of plastic over it, like a trash bag or bubble wrap, just to prevent freezer burn or harm to anyone reaching into the ice box.

 

[jibes138]

Frozen Vodka Tonic

I work with a guy from London and i asked him if he drinks gin and tonics. He said in the UK that is considered a drink for women and that men would never drink it out in public. I was surprised by the response because i thought the Brits were quite fond of their gin.
You might want to try a Mount Gay Rum and tonic, very tasty.
I have a very difficult time finding tonic water in stores. Anyone know why? I only like Schweppes but I can't find much of any kind.