replace through hulls

[terraplane]

My 1973 Albin 25 continues to improve. New motor last year, and this year a hard top roof on pilot house.

The throughhulls are, as far as I can tell, original. Like faucet handles on my outdoor hose fitting! Some are frozen. I'd like some advice on how complex it is to do this.
Can old openings just be sealed up, and new ones put near old entry?

Any info appreciated.

Terraplane

[WillieC]

I found this on Cruisers Forum, worth looking into as well, I might add.

http://www.pbase.com/mainecruising/seacock_primer

Mine too are original and am thinking of combining this work with new bottom paint. I am thinking that re-using old holes is a much better way to go, given the work involved in patching, correctly, old holes. I also have an abandoned transducer mounted on the outside of the hull just waiting for me to knock it off with one of my trailer bunks. It is quite chunky and a very good target. I have no idea how to remove it, short of a sledge hammer. No visible screws on either side, likely epoxied in, and could leave a pretty large hole for repair, which is why it is still there.

Keep us posted. Good luck!

[Northern Spy]

We had our through hull fittings replaced this past winter. Our yard ground both sides of the hull and faired them then installed marelon fittings and seacocks. . We only retained two through hulls, raw water pickups for engine and air conditioning. the others we had abandoned and glassed over. So far we have been very happy with the new fittings, the peace of mind is fantastic. All we have to do when we come and go is open the two seacocks!

[dkirsop]

I replaced mine last year. It was a relatively simple matter to glass and fill the holes I did not want. Removing the old through hull fittings is easily done with a bi-metal hole saw. Remove the valve from the through hull. Outside the boat hammer in a tapered plug and cut it flush with the hull. Drill a 1/4" hole int the centre of the plug. Using a hole saw equal in diameter to the outside thread diameter of the through hull stem, drill through the flange from outside the boat. Strike the flange with a cold chisel and it will fall off. The through hull can then be removed from inside the hull. It only takes about 5 minutes per through hull using this technique.

[WillieC]

Very slick removal method!
What is the consensus? Marelon vs bronze?

[dkirsop]

Marlon is ok for 1.5" and larger. The .75" diameter version snapped when I tightened the retaining nut so I used bronze on all the smaller through hulls.

[WillieC]

What a rat's nest of pricing info out there. But I think I am figuring it out. A whopping difference in Groco flanged seacocks and the apparent difference is bronze handle versus stainless. The rest appears to be identical, 85-5-5-5, and so on.
I am leaning towards Hamilton, but Seamar in Seattle is close in pricing and I need to get over there anyway. And I like to use the locals so they stay in business!
As to the glowplugs, my VP MD17C has individual airfilters for each cylinder and the filter media, oil soaked fiber, is right at the intake at the head. Might be tricky to modify. Looks like the AD21 utilizes some kind of common manifold with a single filter? Will have to do more research, but glowplugs would be stupendous.