Plastic seacock & thru hull fitting leaking

[ipsum]

I have a small leak from below a plastic seacock. It is not tighten properly to thru hull fitting and turns a bit while opening/closing it. Pipe goes straight to the wall, so can't tighten seacock any more.

Any ideas how to fix this leak properly with boat in a water? I can take off the pipe, try to tighten seacock with 180 degrees turn and then add a longer pipe with loop. But I doubt it will tighten all the way to opposite position. Can't tighten it 90 degrees as other seacock is very close.

Also maybe someone know the brand of this seacock?

[HopCar]

If I understand what I'm looking at, that whole set up scares me. I wouldn't mess with it while the boat is in the water. That plastic thru-hull is way too exposed and could break.
Next time you haul, sooner rather than later, replace the whole thing with a bronze or glass reinforced plastic flanged seacock and thru-hull. It also looks like you have a cored hull and who ever installed the thru-hull cut away the inner skin and the core. The whole thing is just mounted to the thin outer skin. That needs to be fixed.

[RaymondR]

I agree with HopCar, that arrangement looks scary. with the big diameter (and consequently relatively stiff) hose passing through the bulkhead it appears that laterally stressing the hose on the other side of the bulkhead could snap the valve off the plastic thru-hull.

[Rustic Charm]

It looks like a Randex to me. I can't comment on the reliability of what I'm seeing as I don't have a glass boat. I'm not keen on Randex valves. They have a tendency for the handles to snap. It does look a bit precarious.

There are several putties you can get to swipe around that thread that will stop it leaking. But if it was me, as a temporary fix I'd get some amalgam tape that you use on electrics and stretch some of that around it. I've even used amalgam tape on my exhaust and it's not leaked since.

When you do replace them I'd recommend Truedesign plastics from New Zealand. One of the few that meets all the standards. My through hulls are welded on, but I've been swapping all my seacocks for trudesign.

Seacocks And Through Hull Fittings | TRUDESIGN