February 28, 2013

Something you pay dearly for

THE TINKLE OF ICE in a tall glass is an entrancing sound. It’s especially delightful when you’re safely at anchor in a pretty cove after a hard day’s sail. But it takes a surprising amount of power to make ice on a small boat.

Weekend sailors mostly make do with ice-boxes, but long-distance cruisers often opt for on-board refrigeration.

The two most common methods are engine-driven compressors feeding supercooled fluid to metal holding plates in an ice-box, and modified household fridges running on 12-volt motors. Holding-plate systems are expensive to start with, and require you to run the ship’s engine for about two hours every day. Fridge systems cost about one-third less, but the electrical draw is heavy and constant.

Your 12-volt batteries will need to provide about 4 amp-hours of power for every hour of refrigerating—almost 100 amp-hours a day—in hot climates. That’s a lot for the average cruiser to replenish, even if the auxiliary engine is running an extra-large alternator. And then there’s the noise of the fridge motor cycling on and off all day and night.

One way or another, you pay dearly for ice.

So learn to maintain your system. There are no repair shops at sea.

Today’s Thought
Most of the luxuries and many of the so-called comforts of life are not only indispensable, but positive hindrances to the elevation of mankind.
— H. D. Thoreau, Walden.

(I think Thoreau got it wrong. He surely meant dispensable, not indispensable. — JV)

“May I recommend the cold tongue, madam?”
“Certainly not, waiter. I couldn’t possibly eat something that came out of a bull’s mouth. Just bring me an egg instead.”

(Drop by every Monday, Wednesday, Friday for a new Mainly about Boats column.)


Anonymous said...

I LOVE your blog!! (and your books of course)

I think this thoreau quote is "... _not_ indispensable" but, you're right, he meant "dispensable"

Sara Johnson said...

The new refrigeration systems are a lot more efficient and affordable than you suggest. We have a Vitrifrigo system on our 12m ketch. We've run 99.9% on solar for the past year in the tropics and enjoy ice every day (and more importantly, cold beer). The compressor is absolutely silent - it is cooled with sea water via a keel cooler. The power I've used to charge the laptop while writing this message takes far more amps than our fridge!

photocurio said...

Small boat cruisers sometimes just plan on no ice. I've found that most brands of stout taste the same if cold or warm. That's out sailing beer.