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
1969chriscraftroamer46 