J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Thru-hulls & seacocks

About 2 years ago the surveyor recommended replacing the corroded head intake thru-hull. I figure it is about time to take care of this "minor" problem. His recommendation was to use a marlon replacement. My though is to use a bronze thru-hull with a marlon seacock. Any thoughts or experiences I can learn from?

I'd check if the manufacturer's recommend mixing bronze and plastic - I remember reading a caution against it (I'll try to locate the reference). I prefer bronze for strength over weight any day. You might want to consider seacocks on all through-hulls - I'm surprized the surveyor did not mention it (unless your boat is already has them on all thru-hulls). I've seen many J's without 'em. It was the first mod I made to the boat.

What sort of through hull did you use for the galley sink, and head sink? Neither of those have seacocks on hull 205

I used Conbraco's from Hamilton Marine, which are like the Apollo's from West Marine. I also put one on the anchor locker thru-hull, and while I was at it, put a siphon-break elbow on the intake side of the head (between the pump and the bowl, but hidden up in the locker with the outlet elbow). Of course, had to epoxy down some backing blocks to raise the seacock and distribute loads. I used the existing bronze thru-hulls; just spun off the barbed fittings, installed the blocks, spun on the seacock, installed the barb, put a screw to hold the seacock from turning, and replaced the hoses.

Do you have a list of all the different sizes for the various thru-hulls? I hadn't even thought of the anchor locker. I figure if replacing one is a good idea, replacing them all is even better.

from my notes:
Head-in, engine & anchor: 3/4" NPT.
Galley sink & Head-out: 1-1/2"
Head sink: 1-1/4".
Remember, seacock raises hose attachment point, so you might need to replace straight barb with 90 deg barb. I ended up with slight service loop in anchor locker that traps alittle water. Obviously if you leave anchor seacock closed, locker fills w/rain. (But fuel port is above lower edge of locker so port should not submerge). Double clamp hoses below WL.

There is a good discussion of thru hulls in the West Marine catalogue. Thru hulls should be straight not tapered as in NPT

As always, lots of great help from all of you. It's about time to break out the wallet and get busy! The days are looking better here in Alaska. It's a challange to fit maintenance and sailing into the short summer.

Good point on the NPT. All seacocks are straight thread on the bottom to match straight thru-hulls. You have a choice on the top of either straight or NPT. NPT seem more common so I used those.