1960s Chris Craft boats all came with bilge vents that went through the mahogany toe rail and were capped by either stainless or chromed bronze scoops, with screens to keep bugs out. But cabinetry in the vicinity of the vents often rots out because of the way Chris Craft routed air and rainwater from the vent hole through the mahogany toe rail and deck to the bilge spaces below.
For the engine room vents, they used solid mahogany boards and pressboard for the chases. They were painted but the joints were never sealed, so water from rain and washing the boat eventually rots the pressboard and then you’ve got water streaming uncontrolled down onto your floorboards and the back of cabinetry panels.
OEM bilge vent chase…or what was left of it
My Roamer was no exception, and there was rot everywhere there was a vent when we started this refit. I fixed the problem with the engine room and transom vents by making the vent chases out of solid mahogany or 3/4″ and 1/4″ marine plywood that I’d sealed with a heavy coat of epoxy and a layer of fiberglass. There’s no way for water to find its way out of those chases until they terminate down in the bilge.
But the side vents in the aft stateroom posed a different problem. As with the engine room vent fan, Chris Craft used flexible hose for those vents and the plastic becomes inflexible over time. When the hose cracks, water falls freely onto the backside of cabinet panels and the rot begins. We essentially gutted this boat because the rot on the original cabinetry was so extensive.
Since we replaced painted OEM cabinetry with beautiful varnished mahogany, I don’t want it to suffer the same fate. So I came up with a solution (actually two solutions…one bad one and a really good one) that worked out just fine.
OEM Chris Craft bilge vent hose gave up the fight a long time ago
That hose looked more like a Slinky in spots than a hose. I’m probably dating myself with that reference…
Anyway, my first plan was to make fiberglass boxes that would act as reservoirs for small amounts of water (1-2 quarts) that came in through the vent holes, while having a clear air pathway to the bilge via solid fiberglass tubing. I figured the water would evaporate from the reservoir and rarely if ever reach the spillover point where it would fall into the bilge.
Making the ‘spillover tubes’
Installing the spillover tubes in a reservoir box
Aft stateroom reservoir boxes ready to install…back in 2015
When making the reservoir boxes, I failed to take into account the tight clearances between the underside of the deck and the side portholes in the aft stateroom, where they’d be installed. They fit in the space just fine vertically but protruded past the plane of the pretty mahogany paneling that would surround the portholes.
So I didn’t install them, and the more I thought about having a half-gallon of water suspended in a box over pretty mahogany, the less I liked my brilliant plan.
Fast forward to 2022, and I decided to scrap my reservoir vent plan
In 2016, I bought an HTP AlphaTIG 200DX and taught myself how to TIG weld stainless. My dry stack exhaust risers turned out quite nicely, and I started dabbling in TIG welding aluminum. I’ve also got quite a bit of leftover 3/16″ 5052 aluminum plate from the side deck and aft enclosure build. So a new plan started to form…
Just to orient you, the vent is above the right edge of the middle porthole, next to the closet wall
A one-liter bottle just fits
The board I’m holding up is in the same position the pretty mahogany panel needs to be in when it’s installed. The vent tube has to fit cleanly behind that.
Chris Craft just mooshed the vent hoses in by brute force. I want there to be a nice, clean fit and no stresses on paneling or anything else. Which means I’ve got just enough room for 3″ square aluminum tubing. For comparison’s sake, fiberglass tubing with the same dimensions costs roughly twice as much.
I bought a 20′ stick of 3″ square 6061 tube and started cutting
I’ve said it before, and I’ll say it again: the Harbor Freight metal-cutting bandsaw is a great tool. I adjusted it for a 10° cut to match the underside of the deck where the vent hole is.
First test fit got hung up
I had to knock off some spray foam insulation for clearance
Nice!
Concept proved!
The vent tube will be entirely behind the 1/4″ pretty mahogany panel surrounding the portholes.
A graphic representation of a steep re-learning curve
Hey, it’s been a while since I TIG welded aluminum. You can tell the first attempted pass by all the carbon (I kept sticking the tungsten to the plate and filler) and just a ball of melted filler sitting on top of the plate. I must have resharpened that tungsten 2-3 dozen times before I finally got sort of back into the rhythm.
I practiced a few hours per day for a week with fillet welds, since that’s what I’ll do most of on this project
After one fillet (inside) and one corner (outside) pass, I cut the welds off and repeated
While waiting for the bandsaw to cut my practice pieces, I marked off the parts for cutting
The piece above will attach to the underside of the deck.
Vent tube side
Looks about right
It’s showtime!
TIG settings
I don’t weld stacks o’ dimes…more like piles of nickels, dimes, and a quarter or two
One concern I had was keeping the relatively small aluminum plate from warping from the heat. So I clamped a big 3/8″ thick section of angle to the plate to keep it flat.
Back at the boat to test fit
Looks about right
I need to trim 1-1/2″ off the right-side edge of the plate, so the tube is closer to the closet wall.
Cutting the walls of the vent box on the table saw
Mocking up the box
Looks about right
Successful mock-up test…back to the garage to weld it up
I used coils of copper wire as heat sinks to draw temp out of the small plates while welding
Tacked on eight corners
Nice pile ‘o dimes, nickels, and a quarter or two
Cutting the vent hole in the top plate
I’ll need two, one for the port vent and the other for starboard
I clamped the top plate to the 3/8″ angle to keep it flat when the heat comes on
Looking good!
Time to tack on the bottom plate and tube
Nice!
BTW, even a novice TIG welder like me can recognize a must-have piece of equipment, and you can see one of them in the picture above. That furry tube next to the TIG torch is a well-worn TIG Finger heat shield. With that on your gloved finger, you can brace your torch hand so much better because it lets you run your bracing finger right over the area you just welded. No heat comes through, and it’s slicker than a TIG glove, so even a weekend hack like me can move my torch hand along smoother than without it. I don’t make any money on this, I’m just passing on what I’ve learned and where to buy them. The seller, Jody, also has lots of youtube videos teaching welding techniques.
Next I took the vent box and tube to the boat to check fit, and confirmed the lengths and angles the additional tube sections would need to be to bring the bottom of the vent tube to bilge level.
Back at the garage, compound angle joints were necessary to follow the hull curve
Tacked up and almost ready to weld
Back at the boat for final test fit
I marked the tube with a Sharpie to indicate where a stringer was down low. I’ll weld a tab on there for a bolt so the bottom of the tube is firmly supported.
Back at the shop, the port vent tube is welded and ready to install
Next day, back at the boat I applied sealant to the vent hole and #10 screw holes
A generous bead of caulk dolloped on the vent box side
Nice!
Even better!
I’ve had these mahogany panels cut, sanded, insulated on the back side, epoxy sealed around the edges, and painted with ICA clear coat base since 2015. But I couldn’t install them until I worked out the solution to the vent problem.
Now that the problem is solved, I just have to knock out the starboard side and move on to the next major step.
I repeated the process on the starboard side
And that’s a wrap for the longstanding puzzle of what to do about those aft stateroom bilge vents. As you can tell from all the trips to the boat and back to the garage, this took many days to finally finish. And keep in mind that each trip involves an hour drive each way. I really do need to get the boat launched in October and moved to a much closer marina…
Next up in our 1969 Chris Craft Roamer 46 Refit: Installing [most of] the Portholes
1969chriscraftroamer46 