H25 cockpit drains
I may have misdiagnosed this but if the small slit is in the through-hull fitting itself, it is there for the wrench needed to turn the fitting as the guy on the other side turns the locknut during installation-- no other reason. Most plastic through-hulls have this or else a peg inside to do the same thing with a different sort of tool.
I made the mistake of 'restoring' my 1974 RC Marine (now Forespar) Marelon through-hulls in the back bulkhead of the cockpit rather than replacing the whole thing. They are awful-- not the parts themselves (which actually held up fine, as they resist UV better than do the more common Perko nylon ones-- ugh), but how they were installed-- not even symmetrically placed, sawn-off to provide a flat in the flange to get them closer to the sole, and still not sufficient for all water to drain out. The procedure upon arriving at the boat is to have someone else stand at the transom to coax more of the rainwater aft and then to sponge out what won't go down the drains. The cockpit sole is a constant morass of brine and slime. I removed them, took more off the flanges to enable them to be lower, and rebedded them in a swamp of 5200; but one still leaks a little (I suspect an invisible crack) and they still don't drain well. I also chiseled some of the bulkhead out to make them more symmetrical than they were; but it's far from perfect.
You may also be seeing a gap under the fittings as I noticed mine were not really willing to perfectly meet the cockpit sole itself but sit a little high despite my efforts to remedy that-- probably due to the radius of the molded cockpit not matching the flat of the back of the fitting flange.
I located a very nice floor drain by Scandvik, that, being Scandvik, is surprisingly IN-expensive-- $17.99 in stainless steel with a 1" 90-degree hose connection. Defender carries them. I can't wait to install these this winter. They have to be set into the cockpit floor itself, the first and only holes I will ever put there (hence its cored deck being perfectly pristine, which no one with a pedestal wheel can boast of!) but the openings can be sealed in epoxy and then the fittings set in 5200. Best of all they are such a close 90-degree turn that the hoses will still run downhill to the transom through-hulls (which ought to have at least check valves if not ball valves on them). Anything else with a 90-degree turn wouldn't work.
I decided to change all 4 of my transom fittings to stainless too as soon as I paint the topsides (spring 2012) as they look better than the chalky but still-serviceable Marelon.
If the factory cockpit-drain fittings are the original 1974 ones I would remove them with a hammer and chisel (which I did not do... doop!) and replace them promptly. If you will go with the same set-up and are happy with sponging out leftover water, be sure to use Forespar Marelon ones (1" or 1-1/8"). Cut them on a bandsaw or with a hacksaw as closely as you can to the threads to make a D-shape out of the flange. And use 5200, behind and below. I did get some nylon drains made for this sort of application at WM but after debating how to paint them to keep them from the UV-- which would destroy them in no time-- I'll put them on eBay and let someone else find a less-crucial use for them. NEVER use nylon through-hulls for anything involving seawater, or in direct sunlight, or mounted within 4-6" of the boottop, or having a potential for freezing when wet. The Marelon ones are not expensive enough to make you think twice-- in fact they're not expensive at all.
And for this cockpit application, bronze ones, and having to cut them, are just not necessary.
I will post pics of the Scandvik ones when I get them done but it probably won't be till spring. I have too many other things to do before winter and the existing system does (albeit with a nearly imperceptible dribble) work as-is. Diana's blog (in my member profile) has a few other pics of the other would-be nightmares I have tackled recently.
