1969 Chris Craft Roamer 46 Refit: Wrapping up the Exhaust Showerhead Plumbing

Getting the raw water supply and exhaust done for my Cummins 6CTA main engines is a major priority for getting this Roamer out of the tent and floating again. I made the raw water tell-tale thru-hulls recently. Now I need to install those and make some tubing to connect the heat exchangers to the exhaust riser showerheads.

Let me apologize in advance for the poor lighting in some of these pictures. The ER is darker in some places than others, and white things in the frame make the camera ‘see’ the dark areas as far darker than they are to the human eye.

The port engine’s HEX raw water outlet and showerhead inlet are pointed in different directions

Oh, and the outlets and inlets are 1-3/4″, not 1-1/2″.

Given that marine exhaust hose is somewhat flexible, the fact that the outlets and inlets aren’t pointed at each other is a lesser problem than that the HEX outlets point directly at the middle of my brand new risers, and the insulation is only 3-1/2″ away.

The starboard side is even worse

The starboard showerhead inlet is on the far side of the riser dry section from the HEX outlet

I’d been thinking about how to resolve this problem, but after spending many hours trying to find pre-formed hose that would work (my on-the-fly, couch engineer assumption when I made the risers), I finally decided to just buy some 1-3/4″ mandrel bent stainless tubing and make some twisty raw water pipes that’ll have short sections of hose attaching them to the inlets and outlets.

One U and one EL will do the trick

vibrantperformance.com had the tubing I needed at a fair price, and the shipping was super fast.

Grab a Sharpie and start marking where to make the cuts on the U-shaped tube

Eyeball the angles and mark with a Sharpie where the U tubing needs to be cut

Starboard side is more complicated

The straight section that I’ll cut off the U-shaped tube I used on the port side will help make the stretch to the showerhead on the starboard side.

The EL wraps nicely around the starboard insulated riser

It was a good decision to go with a long-radius EL for this application. It pretty much follows the curvature of the exhaust insulation wrap. I’ll cut off a bit of the straight section here, and use some of the leftover U mandrel bend from the port side to point the tube toward the HEX outlet on the starboard side.

Back at the garage, I put my Harbor Freight metal-cutting bandsaw to work

Test fit port side…looks good! (sorry for the lousy lighting!)

Test fit starboard side…looks good!

12″ Shopsmith disk sander comes in handy for final-fitting tubing before welding

That’s a professional-grade fit, if I do say so myself

Final dry-fit

I rotated the mandrel bends until everything was pointing in the right directions. Then I drew a Sharpie across each joint in a couple of spots so I can reproduce their orientation back at the shop. I used some tape to hold the joints together for the last, very last, final dry fit.

Back to the garage for some TIG welding.

Tackin’ and TIGgin’

I used my double argon regulator rig to supply the TIG gun and for a purge line that goes inside the tube. I capped off both ends of the tube with aluminum foil and tape, leaving small gaps for air to escape as it’s forced out by the heavier argon shield gas. After a minute or two of slow purging, I tacked the tubes and welded around the joints.

Looking good!

Almost done

Last joint to weld

Done! (sorry for the terrible lighting!)

The Big Day has arrived!

Nice final test fit!

Perfect! Ready for hose!

This is Shields 200 Series, no-wire 1-3/4″ exhaust hose, date stamped May 2022

Boom

BTW, I’m using Breeze constant torque hose clamps in this application.

Port showerhead raw water connections, including 5/8″ tell-tale line, are done

I’ll attach the 5/8″ hose to the thru-hull later

The thru-hulls are currently in use as grommets for wires that need to go outside the boat.

Starboard is next

Absolutely perfect fit, with ~1/2″ of clearance to the riser insulation

Starboard showerhead raw water connections are done

5/8″ raw water overflow/tell-tale hose goes from the showerhead to the thru-hull I made recently

Maybe I should redo those thru-hulls with 90° mandrel bends instead….

Outside the boat, the 316 stainless raw water thru-hulls look good

Ignore the goo that got splashed on my paint in the picture above…it washes off.

Port side thru-hull is being used as a wire grommet

So that’s a wrap for the exhaust raw water system. I still need to install a 2″ aluminum standpipe for the main engine raw water inlets, and connect the strainers. But it’s too hot to weld in the tent now. I’ll wait for late August or September for that. In the meantime, I’m getting more mission critical stuff done in preparation for splashing ASAP.

Next up in our 1969 Chris Craft Roamer 46 Refit: Fuel System Plumbing

1969 Chris Craft Roamer 46 Refit: Main Raw Water Inlets

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.

Starboard engine raw water standpipe

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.

Port side standpipe and dielectric, with the genset raw water seacock below

New raw water standpipes have been waiting around since 2014

Hole saw for the new pipe is big enough to fit over the dielectric

First, knock off the strainer, then knock in a block of wood

Center the pilot drill on the wood and pull the trigger

Hull breach

Standpipe with dielectric

New port standpipe test fit

Repeat on the starboard side

OE standpipe and strainer

Lotsa gunk packed into the strainer

Bad design

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.

Interesting comparison

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!

The view from inside

Port side raw water component test fit

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.

Next up in our 1969 Chris Craft Roamer 46 Refit: My Life Is An Old-School Country Western Song.