Glen Justice
  I never sweat more than when I'm on the boat.
It might be because I'm aboard most often during the hottest months of the year, or perhaps it's that I'm always wedging myself into small spaces. Maybe it's just the fact that the air conditioning unit that feeds the salon simply cannot cool the space. Whatever the cause, I've come to see my trawler as a giant floating sweat lodge, without all the ceremony.
Such was the case this weekend when, moored on a ball in Annapolis Harbor, I went about getting ready for the season as the heat indexed climbed. I found myself increasingly miserable as I cleaned canvas, scoured the grill and scrubbed down lockers, the fridge and the head. (You can get a blow-by-blow account of my efforts on Twitter.)
The boiling point came Sunday. The gauge on the waste water holding tank said three quarters full, so I called the pump out boat to come take care of it. It's a drill I've done many times before: the pumper pulls alongside, I open the deck fill, jam in the vacuum pump and turn it on. The waste gets sucked out, I pay my $5 and off they go.
Not this time.
KABOOM!
This time, as I unscrewed the fill, it started venting nasty goo. Was the gauge off? It said three quarters full! I got some towels and let it run for awhile, thinking I could "bleed off" whatever pressure was forcing the poop on my boat skyward. But with the pump guy waiting, I finally got impatient and opened it up. Kaboom! The boat poop blasted out in a fountain that reached about 10 inches off the deck.
The gauge was, in fact, a little off.
I jammed in the nozzle and completed the task, then set about 40 minutes of nasty work, cleaning dock lines, fenders and what seemed like an acre of soiled topside. When I returned to the salon to wash up, drink some water and breathe, I glanced at the AC panel and that's when the sea Gods delivered their final blow: it was 101 degrees inside the boat. I took a picture.
Fed up, I headed for land via water taxi – the dinghy engine won't start, even after hours of sun-baked coaxing – and landed in a Starbucks, where I alternated iced coffee and iced tea until sanity returned.
The smarter strategy, of course, is to work in the early morning and at dusk, when the weather cools. I've been doing that the last few days, to marvelous effect. But that too has it's odd moments. For example, during a beautiful, temperate sunset the other night, I had to forgo drinks and contemplation on the transom. Instead, I grabbed a gatorade and rushed to tear apart and grease up the windlass, before I lost the light.
I have been searching for the grain of wisdom to be gleaned from all this, and I think I have it distilled to one important point.
"Three-quarters" is the new "full."
Interesting read!
I had a buddy that experienced the same geyser from his holding tank - it's not pretty. My solution to this was the Snake River Acugage system. It mounts externally from the tank and is calibrated for full and empty. With no moving parts, it has never failed (and there is an alarm when it gets to 80% full). The entry level unit is around $125 complete, and has sensors for water tanks also (if they are plastic).
As for your AC problem, I've had the same issue on my last two boats. My current boat has a 17k btu AC unit and it still doesn't work. The problem is in the venting. It's under the stairs to the sundeck with the return on the side of the steps and the vent just in front of the steps. So the bottom step is really cold - the rest of the boat, not so much. I was planning on reducting, but haven't got to it yet. My solution was to mount 2 strong DC fans in the middle of the salon, one pointing fore and the other pointing aft. This really circulates the air and drops the whole salon temp.
The same solution worked in my aft cabin also (which gets blistering after a few days of cruising. It seems my engine rooms bleeds off its heat through my cabin!)
Fans placed in stratigic 'dead air' spots can really make a difference. I may still add some ducting, but I haven't missed it this year.