With the exhaust system almost done (the high temp resin finally arrived for the insulation hard shell), I’ve started doing the prep work to replace the original 1-1/2″ raw water inlets with 2″ inlets that my Cummins 6CTAs require.
Chris Craft used dielectric unions to separate the bronze fittings they used on the inside of the metal (steel and aluminum) Roamer boats from the raw water standpipes that are welded to the hull. I was able to remove the dielectric on the starboard side with a pipe wrench but not the one on the port side. Fortunately, the new standpipes require a hole big enough for the dielectric to slide right out.
The back side of the original strainers, which appear to be a Groco product, can’t be epoxy coated after they were welded in, and the hull in this area was bare aluminum, too. Add a bunch of dirt packed into the lee side of the strainer, and it’s a recipe for corrosion. Fortunately, there was only one deep pit on each side, and I positioned the hole saw to cut through it. My new strainers are also from Groco, but they’re hinged. Once they’re welded in, I’ll open the hinges and put an epoxy barrier coat on them inside and out. Plus, when I periodically haul the boat for bottom paint I’ll be able to clean out any accumulated gunk.
On the left we have the welded area where Chris Craft joined 5052 aluminum hull plating to 6061 aluminum pipe. Even though there was no barrier coat here and the boat ran for a while in salt water, there’s very little corrosion in this area in spite of the different alloys. On the right, we have badly corroded pipe where the steel part of the dielectric threaded on. The green suggests that copper from the bronze fitting attached to the other end of the dielectric was playing havoc with the aluminum. I’m glad I decided on Marelon seacocks for the refit!
I’m still deciding where to place everything. I want to maintain ease of access to the outboard side of each engine, but the inside strainers need to also be accessible for maintenance. I think this arrangement is a pretty good compromise.