Bronze or meralon ball valves and thru hulls?

[ChrisCall]

Ok decided to haul out to replace leaking engine raw water intake thru hull and ball valve . In my 1989 Catalina 30. Should I replace it with another meralon or go with bronze?

 

[Don S/V ILLusion]

Can't help but ask - What happens if you get three disparate answers from the three forums in which you post this?

Fyi - it's marelon. Too many failures reported and stuck valve complaints on marelon fittings for me to even consider them

 

[Scott T-Bird]

I think I'm going to sit back and watch this one ... sorry, no opinion yet, but I have marelon, too. I've had no failures or issues with sticking since I use white lithium grease occasionally. My thru-hulls are almost 30 years with no visible sign of distress. Mainesails tests show how easily marelon can break when taking an impact blow. That would be something to consider if you have any loose or semi-loose items stored in proximity to thru-hulls.
I've had my marelon y-valve fail on 2 occasions, though, which reminds me to replace my current valve ASAP!

 

[ChrisCall]

Just took it apart it was actually the wooden backing plate rotted. Should wood be used as a backing plate or something like a starboard? Also what should be used as sealant when new one is installed?

 

[jibes138]

Use G10 material for a backing plate. You can buy it at McMaster Carr and cut it out with a jig saw to size. See MaineSail's website for how to replace a thru hull and seacock. Very thorough and includes what sealant to use.

 

[capta]

If it was my boat I'd use a proper silicone bronze seacock (not ball valve). All of my seacocks have wooden backing blocks glassed in and none show any deterioration yet, but it's only been 35 years.

 

[kerryedwards]

What kind of wood was it which rotted? I have a fair amount of scrape Ipe around which I have been using.

 

[thinwater]

Why resist using fiberglass? By the time you epoxy and glass in wood, what did you save?

G10 is probably overkill in such a low-stress compression loading. Structural grade will be many times the strength of wood and 1/3 the cost of G10.

I'd cut it with a hole saw; no stress risers in the corners.

 

[jibes138]

You might find some fiberglass scraps around a boatyard from a boat they demolished or a holed boat getting fixed. Wood will certainly work but why not use something that will never rot ?

 

[Chris & Lenore]

You can easily and cheaply cast your own fiberglass backers. Find a plastic container the diameter you want. Get some fiberglass cloth or matting and cut it into shreds or unravel it. Get a can of polyester resin (no need for epoxy).
Mix the resin and alternatively pour into the container and add fiberglass. Make sure the cloth wets out. You don't need a ton of cloth... Make it whatever thickness you need and let it harden.
Pop it out of the container and sand the top smooth. Done - takes about ten minutes effort.

Chris