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Keeping Cool
Question:
How do on-board air-conditioners / heaters work? Should I be on the lookout for anything in particular when looking for a boat with air conditioning?
The Lillie Family wrote:
Why on earth would you want air conditioning when you have all that fresh air? Make 'wind tunnels' that capture the air/breezes and funnel them below deck.
Doug Abbott wrote:
Very_ poorly, very_ expensively, and very_ noisily! You need lots of amps to run the AC. Most boat AC's only run when the generator or engine is on. Kind of kills the peace and quiet and beauty of an anchorage, doesn't it?
You won't need it; you only think you will. Sure, there will be days when it's popcorn hot. You just do something else - go to the pool, go snorkeling or diving, go work on your tan, go do nothing, go sailing and work on your technique, go to the mall, go to the movies, go somewhere where you can cool off. You'll acclimate quickly and learn to do things in the early morning and late afternoon or at night.
Buy lots of 12V fans. Those will be used far more than the AC.
Tracy Watkins wrote:
Built in A/C units work essentially the same way your heat pump does at home. The main difference being that the marine system picks up raw water and circulates it through a heat exchanger to reduce temp.
Stuart Jantzen wrote:
There are on board ac units that work off an inverter (110V converted from 12 V). They can be very effective. We have a regular window air conditioning unit (110V) that I have installed in the forward hatch. While at the dock, it works great!
What I
decided (1998):
The last weekend in July, I visited approximately 30 boats spread all over the eastern coast of Florida. Every boat we visited was absolutely stifling hot! There is NO WAY I'd live on one of these boats without air conditioning--for fear I might drown in my own sweat! So, I've decided that air conditioning is an absolute must.
I did learn there are two types of marine air conditioners...window (hatch) units, and central units. I was advised by several people that the hatch units won't efficiently cool a large boat, so I decided on a central unit.
(22,000 BTU) was about $1,600, and it cost $1,400 to have it installed. It works absolutely great! In fact, I let it run all night on full-speed just to see how cold it would get. Imagine my surprise when I woke at 4:00 in the morning, shivering, because the temperature inside the boat had dropped to 62 degrees (this is practically freezing by Florida standards)! Even during the day, the unit keeps the boat nice and
cool.
Thoughts
from 2000:
There are three ways to keep a boat cool in the Florida sun. The first is to create an awning, which is a fabric covering that is installed over the top of the boat. Typically, these awnings allow about 3' of space between the covering and the deck. They have to be custom-made, are relatively expensive, and certainly hamper the sailing experience!
The second way is to install a "hatch unit" air conditioner. The problem with these units is that they allow a lot of the cold air to "escape" because they're notoriously difficult to seal. Some people (insane, mostly), install these units in their companionway hatch. This makes it VERY difficult to enter / exit the boat!
The third way is to do what I did...have central air professionally installed. Quite frankly, having central air on a liveaboard boat in Florida is an absolute dream! I don't have to worry about awnings. The system has a computer that is identical to the control units that one might purchase at Home Depot for central air. It's smart enough to know what day it is and how cool I want things in the morning versus afternoon.
Perhaps the wisest purchase I've made since moving aboard is this central air conditioner. It does not interfere at all with my sailing activities (i.e, I don't have to take apart an awning or remove a hatch unit), and it keeps the boat very, VERY cool during the summer. In fact, one of my liveaboard friends recently referred to Candide as a "meat locker" because of its climate controlled nature.
Central air is a great investment!
Thoughts
from 2003:
One thing I failed to
mention in the past five years is that the A/C unit aboard
Candide is reverse-cycle. That is, it produces both
cold air during the summer and hot air during the
winter. I think I've already made the case for
having cold air during the summer, but it's winter now and
I'm enjoying hot air to heat the cabin. Last night,
in fact, it dipped into the mid-30's. Quite cold for
Florida this time of year! Quite frankly, I didn't
know that the temperature had dropped so low until this
morning when my fellow liveaboards were complaining about
how cold they'd been aboard their boats! During the
winter, while Candide is docked (I have to draw shore
power to run the heater), she stays quite warm. The
trick to keeping warm is three-fold:
 | Reverse-cycle air
conditioner. If you're going to purchase an
air conditioner to keep your boat cool during the
summer, it's my opinion that you should spend a few
extra bucks to buy one that can also produce heat
during the winter. Aboard Candide, it's a simple
task to throw a switch ("heat" and
"cool," they're labeled on the thermostat)
twice a year to keep the boat at a comfortable
temperature year-round. 22,000 BTU's of heat is
a LOT of warmth! |
| Ceramic space
heater. When it gets really cold in
the dead of winter, I use a $30 ceramic space heater
that I purchased from Wal-Mart. It's a simple
device that plugs into a normal 120V outlet.
During the day, it keeps the saloon nice and cozy
warm. At night, I put it on the floor in the vee-berth
to keep that cabin nice and toasty. |
| Electric
blanket. I don't know why more of my
liveaboard friends haven't thought of this one.
They usually act surprised when I tell them that I
have an electric blanket in the vee-berth. I
usually turn it on an hour before I go to bed.
When I crawl under those sheets, it reminds me of my
college days when I had a waterbed with a built-in
heater. It's so...warm! The heat
usually puts me to sleep in just a few
minutes. |
"Why does one need
so many sources of heat while living in Florida?" you
may be asking. Well, the primary culprit is the
water temperature of the St. John's River. As we all
learned in Thermodynamics 101, a dense, cold body of water
will suck heat right out of the air. Immerse a boat
(filled with air) into cold water, and you'll soon
discover that that the water is stealing your
warmth! Hell, just in the past two weeks I've
noticed that the boat's tap water is much, much
colder than it is during the summer! The St. Johns
is even sucking the warmth from the water tanks (not that
I'm complaining...I like to drink cold water throughout
the day...only now, I don't have to put a jug of it in the
refrigerator...it's quite cold enough directly from the
faucet)!
Perhaps now you're
thinking, "Well, gee, isn't it expensive to pay for
the electricity to keep a boat well-heated during the
winter?" The answer is (the environmentalists
will hate this)...I pay the same amount for electricity no
matter how much or how little of it I use! There's
simply no incentive for me to "conserve"
electricity because the marina charges $35 per month
regardless of how much juice I consume! So, my
attitude is that if I'm paying one rate, no matter what,
well...I might as well be warm during the winter!
Aboard Candide, you'll find a primary heater, a space
heater, and an electric blanket...all running at the same
time during freezing weather! This is one of the
huge advantages of living in a marina that doesn't meter
the electricity consumed by each boat!
Please
drop me a line at:
robert@sleepingwithoars.com
©
2007 by Robert Doty
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Perhaps the wisest purchase I've made since moving aboard is
a reverse-cycle central air conditioner. It does not interfere at all with my sailing activities (i.e, I don't have to take apart an awning or remove a hatch unit), and it keeps the boat very, VERY cool during the
summer and warm during the winter!
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This
past August, I woke up at 3:00 one morning because the
boat was so hot. I could hear the
air-conditioner cycle on and off. This is a
strong signal that the unit isn't able to pull cooling
water from the river. Usually, this is caused by
a clogged strainer...but I had just cleaned the
strainer that morning! I got out of bed, pulled
up the floor panel, and checked the strainer. It
was very clean! I then checked the
through-hull. It was fine. The culprit was
in the 90-degree brass elbow connecting the
through-hull to the strainer. It was clogged
by...a fish! A friggin' fish had swum into the
A/C unit's cooling lines! The poor fellow was
dead by the time I found him (the suction from the
pump had separated his head from the body). I
used a screwdriver to dig out the remains of the fish
from the cooling lines, and reattached
everything. The A/C came to life and it didn't
take long for the boat to cool down so that I could
sleep. It's little instances like these that my
landlubber friends just simply don't
"get." But it's all part of living
aboard a boat!
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