Commander #65 "Lucky Dawg"

[ebb]

Feel like this nutcase in the end of the bar we need to avoid because he's got
an opinion on everything....

If we must have a few thruhulls, why not install them as a maintenance item,
make them easy to 'service'.

Make sure the hole itself is in good shape, it can be restructured with epoxy.
Consider a large backing block permanent. If you do, you can epoxy it into
place and drill the thruhull hole cleanly thru it as well as the hull. The backing
block can be wood or plywood, but better if fiberglass sheet or G-10.

Consider bolting the seacock on butyl tape. Get it off latter, any time.
Threads running into the seacock can be brushed with lanocote.
{Lanocote is a sheepwax product sold inexpensively by the jar, produced by
Forspar. They, being foreigners, call it corrosion inhibiting lubricant...
but it actually is a very sticky, non-runny, marine grease extracted from
sheep's wool. Smells important, too!}

Prefer first to have the seacock solidly fastened in place, with shut-off handle
and hose lead where destined to live forever. Seacock cinched up strong as
if structurally part of the hull. Butyl stays active as a sealant squeezed into
a thin film. But before assembly, you can lay into the tape a circle or two of
10# nylon leader, to assure glue-line after fasteners are tightened home.
Apply lanocote to bolt threads, and into the drilled holes with a small stiff
art brush, or mini bottle brush.

Run a bead of rubber sealant like 4200 on the inside of the thru-hull flange....
The curmudgeon, at the end of the bar, wiping foam off his mustache from
a fresh drought of ale, sez, he don't advise this... if the assembly is shipshape
no water will get in, and if it does it can't get by the seacock.
Should lanocote get up into the valve chamber: there is no better lube for the
valve ball. The fitting will be able to back out without becoming a federal case.
Lanocote also acts as a galvanic barrier between dis-similar metals.
Will not harden. Why glue the thruhull rim to the hull?

As the clincher here, from outside, screw the thruhull into the seacock. If it's
a new one, and you forgot to dry fit the assembly, you can still back it out
and cut it shorter until the flange seats flush with the hull.*

Thread the thruhull deep as possible in the seacock.
Back the flange at the hull with tube rubber sealant if you must. But really, a
home- made EPDM foam gasket, or O-ring, or just lanoline is mo'betta.

If the hole the thruhull goes into is waterproof -- it should be, using a method
like this -- then the thruhull fitting doesn't need to be bonded in place - because
the finely-fitted seacock you bedded and bolted to the hull is protecting it.

Thus, with the seacock closed, you can remove the thruhull fitting underwater
- scrape it into pieces on a rock-- or sail around the world without it -- not a
drop getting inside the boat. {we do sail with seacocks closed...right?}
Thruhulls that can be unscrewed, maybe hard to get it started. Recall it's
not bonded, it can be undone. And the !@#$%! PITA seavalve stays intact .

It's ready to be disassembled, without insulting the gods, a decade from now.
imco
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* If we have, under the seacock, a substantial backing plate permanently
bonded with the hull, we can then use a chamfered flange thru-hull fitting.
Arguably, this requires a more picky and less substantial chamfered hole in the
hull. (Mushroom requires a much easier straight through with the protective
flange capped over it.) But it eliminates the mushroom hickey. It looks right,
hole less pronounced. Haulout prep easier, and the hull has way more 'ing'.