Bronze Porthole - how tight?

[dmksails]

My boat has a number of really nice bronze portholes, each with 2 screw down latches.

I'm worried about screwing them down too tight or possibly cracking the frame by not tightening both screws equally.

So how tight is tight enough and is it possible to crack the frame by not keeping equal torgue on the screw downs?

[UNCIVILIZED]

The odds of cracking the frames is pretty low, & it's not something I've ever heard of, even in all pastic ports. Though going loco when tightening them will make it so that you'll need to replace the gaskets sooner, due to excessive compression causing permanent dents in them.

I'm not sure what you have for levers or knobs. But as a guide, if you have wingnuts, or knobs of a similar diameter, you'll want to stop tightening things a little before there's discomfort from the pressure on your fingers. And if the levers are longer, then use proportionally less force.
The threads are doing most of the clamping work, & don't really need much help from you.

Also, you can start with them a bit loose, & tighten things up a bit if you're seeing small leaks. Which is something that you can test for anytime, via a bucket full of water or a hose. Just put a towel down first to catch any drips.

[Reefmagnet]

You'll more likely snap the actual screws before busting the frame. If you need excessive force to stop them leaking then new gasket seals are in order as they harden and fail to seal well with age. I've just discovered that a softish neoprene in a round profile makes an excellent replacement seal material. Needs little screw down pressure to form a watertight seal. I use the same stuff as a seal in my pool chlorinater and it holds up under even the pump pressure without leaks.

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[dmksails]

Should have thought of testing them. Next time on boat I'll hit them with the hose and see how they do.

Thanks!!

[Cheechako]

It depends on the type of seal you have. To me the hollow centered ones are best. Just squish them a little tight, too much tightening just degrades the seal. Those seals are readily available in many shapes including D shaped BTW. If it requires too much tightening replace the seal.

[Cadence]

Originally Posted by dmksails

My boat has a number of really nice bronze portholes, each with 2 screw down latches.

I'm worried about screwing them down too tight or possibly cracking the frame by not tightening both screws equally.

So how tight is tight enough and is it possible to crack the frame by not keeping equal torgue on the screw downs?

You are unlikely to break the frames more likely the screws. They don't need to be dogged down very tight. Their grommets being compressed will seal them.

[knockabout]

tighten them till water tight