T&T: AC question

[2elnav at netbistro.com]

I would challenge this on technical grounds.
Going bigger than needed will certainly require running a genset 24/7 when
anchored. When you look at genset maintenance many of the older sets
recommend 50 hour interval. The new ones stipulate 100 hour intervals.
There are 168 hours in a week.

Yes its true that many production boats are badly insulated. Adding
insulation is one of the better expenditures you can make as well as
additional eGlass films to keep out solar heating radiation.
Quite apart from the frequent oil changes needed if you choose to run a
genset constantly, there is also the fuel burn. Even if you are as rich as
Bill Gates, the nuisance of having to stop in for more fuel frequently
cannot be discounted.
A bigger genset has more mass and this makes it harder to dampen the noise
and vibration compared to a smaller genset. Bigger A/c  means larger start
surges. And that is what really determines size of genset. A generator has
to be able to cope with peak load not average load.  So if you go big on
the A/c  sizes  and then decide to only run one little unit for sleeping;
you are running the big genset under light load conditions.  Not good for
genset life.

There are better ways than brute power and an energy wasting approach to
air conditioning a boat. Even down south.

Arild






> My advice - go big.  Boats are horribly insulated.  Only go small  if you
> cannot handle the amp load when a big one kicks on.  And the $/btu  is
> much
> lower in the larger capacity units - like gensets.  Jim
>
>
> In a message dated 4/23/2009 12:00:50 A.M. Eastern Daylight Time,
> trawlers-and-trawlering-request at lists.samurai.com writes:
>
> Question  is: is 9000 too small?, should I go to 12000 or better to have a
>
> smaller unit running all the time than  to have a bigger unit   cycling?
>
> I also considered getting a single 16500 unit to cool the  salon AND aft
> cabin....
>
>
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