I don’t think I’d want Stainless through hulls or valves. Stainless suffers when deprived of oxygen and crevice corrosion is the result. I once had to dig out a stainless steel stern tube and replace it with a GRP fitting - nightmare job. Wrapping insulation tape around bottle screws in the standing rigging is bad practice for the same reason.
Good info from Maestrini. I have written various articles and posts that say pretty much exactly the same. They are covering themselves to some extent, for example a DZR valve on a bronze skin fitting would not come to much harm, but now that the whole seacock can be DZR this must be the way to go.
Thanks Vyv, only one other thing I spotted- ASAP DZR valves have chrome plated balls. Hope its thicker/ better than the stuff on my motorbike that rusts in the rain!
Ball valves are always plated either chromium or nickel, to provide low friction against the seals. It seems to me that the failures on brass balls are initiated in the brass, although it is difficult to be certain.
Sounds like a good reason. I've found that dzr ball valves/thru-hulls do last a long time. I've only had one fail, and not catastrophically. It jammed in the closed position. I guess as long as we use types designed for marine application we will be ok. Just need to keep an eye on them as a regular maintenance item.
One way to extinguish the fire?