Has anyone ever blanked off a skin fitting rather than removing it? This is for under the waterline but the boat is kept on a trailer. I was thinking of filling with Sika 291 & fitting a blanking cap however I'm pretty sure most plumbing fittings are brass which from memory is a no go with salt water? Has anyone ever seen a bronze blanking cap?

Yes we have unused loo skin fittings which are simply capped off with what I assume are bronze caps simply threaded onto the skin fitting. I thought they would be easily found on line but cannot. These people should be able to assist?

www.jpwmarine.com.au/bronze-skin-fittings-rwb1470

I rang JPW - they cannot assist.

Here is a uk site mentioning bronze caps as you say. Maybe email this surveyor and get the suppliers of the caps in the uk and order one?

yscsurveys.co.uk/blogpost/?blog=6&title=Redundant-seacocks

Thanks R13 will look into it.