We'll call this the "Menehune Modification" to the Whitby/Brewer fuel tank vent issue.
For non-sailors the essential issues are these:
Your boat has some fuel tanks. Red Ranger has one. Sister ships have as many as three.
A fuel tank needs an air vent. Fuel going in will displace air, which must go out. Conversely, when the engine is running, fuel goes out and air must go in.
Now comes the difficult marine architecture issue.
Where does this vent go?
The not-always-obvious answer is "Above The Level of the Fuel Fill". On many boats, the fuel fill is a deck fitting. That means that the vent must be above deck level.
This isn't always an easy thing to do. To rise above the deck, the vent hose has to go through the interior somewhere and pop out through a pleasant-looking vent fitting on the side of the cabin.
On the Whitby's — sadly — this hose went aft, to a fitting that was below the level of the tank. Below.
Let me emphasize the below-ness of that.
You're filling your tank with diesel. Floating in pristine, protected, wild-life-filled waters. And when the fuel gets near the top of the tank, some will splash around down there; some of that splashing is into the vent line. Where air is rushing out as the fuel rushes in.
Now you've got a hazmat cleanup issue: diesel floating on the water.
And this was a risk every time we fueled. Vigilance meant climbing down the stern ladder with a rag to catch the drips from the vent line.
The Menehune Modification
The simple and idiot-proof solution is to reroute the vent line.
(So happy that John C. — formerly of Menehune — noted this so emphatically.)
The design goal is to remove any human intervention from taking on fuel cleanly. That way the omnipresence of idiocy doesn't matter any more.
John C. shared pictures of his starboard fuel vent located above the hanging locker. There's a complicated bit of joinery just aft of that locker. The aft bulkhead runs just under the cockpit seat edge. There's a fiberglass headliner for the interior space. There's fiberglass deck which is offset from the interior glass, leaving a small gap. And up on the deck there's actually a molded-in fiberglass box with the winches on top.
We could — in principle — run the vent hose out of the hanging locker and into the winch box. With some care, we might be able put enough goo around the hose to prevent water running from winch back back into the hanging locker. This isn't too appealing because I'm not a fan of lavish goo.
I'd prefer to use a double-ended through-bulkhead fittings. If seen this advertised for plumbing fish tanks and live bait wells. The smallest are ¾" and we only need ⁵⁄₈". I might be able to make something like that work, but it would involve drilling and cutting in a right awkward position inside the hanging locker. I can't fit my shoulders in there, so there's a strict limit on how much work can be done without dismantling the interior cabinetry.
The Red Ranger Alternative
Here's a closeup of the top of the aft hanging locker.
The metal box on the top-left is how we give orders to Mr. Benmar. In the cockpit, there's a control panel with two knobs to dial in a course. The wire arcing out of there goes down to Mr. Benmar's personal compass hanging in the aft berth.
[Yes, our autopilot has a name. We like Mr. Benmar. He grunts and swears a lot, but he's trustworthy and reliable. But he has his own personal compass.]
The wooden structre in the middle of the image covers the electrical tie. It hides two big 30A plugs that we can use to plug Red Ranger into shore power.
The box comes off comes off to reveal a tangle of wires related to the aft VHF station, Mr. Benmar, and the two outlets.
And a space below the outlets into which we can drill to put a deck fitting.
This means that the vent hose could possibly snake through the hanging locker in parallel with the electrical connections and pop out the top of the locker and run overboard through a pretty-little vent fitting just under the eletrical connectors.
If only the vent hose was routed that way. It wasn't. The vent hose was routed down low. After all, the vent was about the level of the aft bunks. Low.
About the Deck
The deck is fiberglass. The interior is teak. How thick is it? It can't be that thick, right?
It's that thick. Almost 1¼" from inside to out. The deck is actually a two-part sandwich: fiberglass and balsa core material. The teak is not just a strip of veneer: it's got to be ³⁄₈" thick. The fitting, of course, doesn't have 1½" of threads; it's barely got 1". So there's a two-tiered hole. The vent line hole is skinny. Then there's an inner hole the diameter of the backing nut.
The rest is just rubber hose and hose clamps.
Here's how the hose looks on top of the closet. The old wooden cover conceals this little elbow fitting perfectly.
I could have used expensive hose with a wire support that might make the turn without kinking. Instead I used cheap hose and an expensive elbow fitting. Sigh.
Inside the hanging locker, I installed a Racor LG-100 fuel-air separator. This is totally a "belts-and-braces" level of over-solving the problem.
And yes. The hose goes entirely under the closet rod. It's a little awkward to hang sweaters ("jumpers" or "wooley pulleys" ) down at that end of the locker because the hose is there.
We'd like to test it. But.
The tank is still almost full from when we topped off the fuel in Norfolk in the spring.
Don't forget to search for "menehune" on the web.