Suggestion: Make sure you exercise your deck caps...

labatt · #1 (**permalink**) 09-05-2009

Case in point - we haven't used our pumpout deck "fill" since late February as we've always been places that we could go directly overboard. Now that we're back in inland waters we went to remove the cap and it wouldn't unscrew. We tried everything (except for heat since it's filled with methane). Finally, we pulled the whole old unit off and put a new unit in. We could then heat the old unit red hot, and only once we used a sledgehammer could we pull the cap off of it. What did we find? Apparently, it was 304 stainless, or something of the sort (it was magnetic) and the threads were completely corroded. If we had pulled it off every so often, we would have probably been OK, but we didn't. So... if you have deck fill plates that you don't use regularly - use them or lose them!

mitiempo · #2 (**permalink**) 09-05-2009

It probably wouldn't hurt to wipe a bit of waterproof grease on the threads if you're not going to use regularly. Also, I recently worked on the head plumbing on a 38' sportfisherman and the through hull valve wouldn't budge. The owner will replace next haulout. How many exercise through hull valves regularly on for example cockpit drains? All should be opened once a month but I bet the ones under the cockpit get closed and opened the least.
Brian

btrayfors · #3 (**permalink**) 09-05-2009

Good advice.

I recently did a delivery on a 40' trawler which hadn't been run in at least five years. The all-bronze fuel fill caps were both frozen solid. They resisted large deck keys, hammers, PB Blaster, and all the usual stuff. It was almost a no-go, because there was no way to sound the tanks to find out if there was any fuel in them.

Finally, a punch and a lot of whacks with a 16-oz hammer got one of them to open. The other staunchly refused to budge.

Check your deck-fills often :-)

Bill

jjablonowski · #4 (**permalink**) 09-06-2009

A little goes a long way.
TEF-GEL - Ultra safety systems - Home page

Omatako · #5 (**permalink**) 09-07-2009

Conversely, it's also true that deck caps don't always close the way you think they do.

We had two tanks contaminated with brine on a voyage because the O-rings had gone hard and assumed the shape of the fitting and no longer sealed, even though they were tightened down hard.

It's thus a good idea once in a while to change the O-rings and make sure that you don't get seawater leaking into your drinking water.

roline · #6 (**permalink**) 09-08-2009

You should be able to find VITON Orings to replace the standard NBR ones that most mfgrs use. Viton can not go as cold, only -35 F, but will go to over 400f and is more stable to fluids, ozone compression set, etc...
I replaced mine over 4 yrs ago no issues to date and I keep a spare set on board. A little silicone grease goes well with both the threads and the Orings. Easy on, easy off.....