Dry Ice....

[NYSail]

So leaving on a 3 week cruise. Have everything together but now considering a cooler for the transom to put veggies and stuff in with dry ice. Hear for the frig effect (not freezing items) you put the dry ice on the bottom and stack your stuff on top. Does the stuff work good for long periods or is it just a few days of cool fun then we are done. Thanks!

Greg

 

[dlochner]

Dry ice (frozen CO2) is very cold, but it doesn't take much heat energy to cause it to evaporate. My understanding is it is good for short term cooling but not so good for the long term, much less effective than ice. I'll leave it to the real chemists here to explain why.

 

[justsomeguy]

Hear for the frig effect (not freezing items) you put the dry ice on the bottom and stack your stuff on top.

That's exactly right. Wrap it in a clean towel. Works great.
Its longevity will depend on how often you open the lid, of course.

 

[Brian D]

I think I asked about this not too long ago. Try doing a search. If I remember it was not recommended due to gassing.

 

[Don S/V ILLusion]

As a general rule, dry ice sublimates at the rate of approximately 10 pounds every 24 hours when stored in a quality cooler. For a “few days”, you’re “gonna need a bigger cooler” to coin a phrase

 

[MikeHoncho]

Perfectly fine if stored outside. Had a two people die locally from CO2 when they had several coolers filled with dry ice in there car for a extended amount of time.

 

[jviss]

For three weeks of coldness I don't think a cooler deployed outside will do it, regardless of whether you use dry ice or regular ice. Other than that, the quality of the cooler would dominate, not the type of ice.

I'm surprised that for a boat that size you'd need more than the built-in fridge affords for a three week trip. How many people?

 

[NYSail]

The boat frig and ice box is large and functions well...... and usually fine. With my batteries I can get 3 days easy with the unit cranked while on anchor before I have to recharge. Just looking to save energy and move items we use more. I will have solar for this trip..... not a huge configuration but 175 watts to give me a little boost. We usually have a cooler inside the boat for drinks and such. Just looking for new options.... a friend told my wife she had dry ice last 2 weeks in a cooler on her boat.... She sometimes exaggerates and I was skeptical and thought I would ask.

Thanks all!
Greg

 

[jviss]

I put a couple of blocks of ice in the bottom of my boat fridge and turn on the 'fridge. After two weeks I still have some ice in the bottom. I think it's pretty well insulated, and the fridge is relatively new and works well.

I, unfortunately, don't have the room on board for a cooler, and I wouldn't want to obscure the swim platform with one. Maybe I could strap one to the coach roof in the spot intended for a life raft.

 

[dlochner]

Ice works well as a cooling agent because it takes a lot of energy to get water to transition from the solid form to the liquid form. It is the energy required for the transition, not the actual temperature that keeps things cool. While dry ice starts out colder, it does not require as much energy to warm and transition to a gas. Dry ice works well for quick chilling or short durations, but not so well for longer durations.

Before investing a lot of money in food that will spoil, buy a chunk of dry ice and put it in the cooler to see how long it will last.

Before I had refrigeration on my boat, I learned to thoroughly pre-chill the icebox for several days before leaving on a cruise and to get the food and beverages as cold as I dare before loading the icebox with the food and beverages and fresh cold ice. A block of dry ice in the cooler overnight before leaving would probably do a good job chilling the box and then loading it with pre-chilled food and good ice. Keeping the cooler out of the sun will go a long way to preserving the ice.

 

[Justin_NSA]

Practical Sailor did a feature on this.

Making Ice Last - Practical Sailor

Since 1974, Practical Sailor’s independent testing has taken the guesswork out of boat and gear buying.

www.practical-sailor.com

 

[jssailem]

I learned if you want to keep your meat frozen dry ice is best.

 

[Justin_NSA]

I thought I was over this once I got my refrigeration working. I discovered last night that one of my neighbors screwed around with the power at the pedestal and disconnected me! I was all thawed out. At least I know for sure now that it shuts down before it completely drains my batteries. I tie wrapped my outlet cover.

 

[jssailem]

Neighbors can be such a hassle.

 

[Justin_NSA]

Neighbors can be such a hassle.

Yep. At least nothing expensive was wasted. Only my beer wasn't as cold as I like it. I've drifted away from my German roots.

 

[dlochner]

As usual, there is no one right answer. As the P-S article says, for keeping frozen things frozen dry ice is probably best. For keeping cool things cool, block ice is probably a better choice. Check the video below comparing dry ice, block ice, and cubed ice. The residual water from the ice kept the cooler cool longer after the dry ice, although the dry ice was colder at the beginning. The water ice kept the temperature more consistent. Once the dry ice sublimated, there was nothing left to stabilize the temperature.

For @NYSail's application, dry ice is probably a poor choice as the temperature will be too cold. It will however keep the steaks frozen. But who wants frozen tomatoes and lettuce?

 

[jviss]

Practical Sailor did a feature on this.

Making Ice Last - Practical Sailor

Since 1974, Practical Sailor’s independent testing has taken the guesswork out of boat and gear buying.

www.practical-sailor.com

Thanks for sharing this. But, I was considering subscribing until I read this article! Then I thought maybe it was an old article - but it's not, it's from 2018, updated in 2020. The thing is, it treats coolers as if coolers are coolers; like, the "36-quart Coleman" is the benchmark. It ignores the fact that Yeti created a revolution in coolers in 2006, and theirs, and their imitators', are far superior to what had gone before, and compared to garden variety, inexpensive coolers like Coleman. Seriously, the Coleman 36 quart cooler is $27. at Wal-Mart. The Yeti Tundra 35 quart cooler is almost ten times the price at $249. And there''s a world of difference in performance, too.

The idea of wrapping a cooler in a fleece blanket or sleeping bag on a boat is just a non-starter for me. I'd rather spend the money on a higher performance cooler that doesn't require that.

 

[Justin_NSA]

I think they just wanted a standard benchmark. The added insulation could compare to a newer cooler. Wouldn't the ice options still perform the same against one another?

 

[Captain Larry-DH]

Placing a cushion on top to shade and insulate it will help a lot.

 

[Jackdaw]

I'm surprised that for a boat that size you'd need more than the built-in fridge affords for a three week trip. How many people?

I was wondering the same thing... no stopping for local provisions? Of course there are trips where this is impossible or impractical (double that in the age of Covid), but stopping for local supplies and produce is part of the fun.