bending tubing « 1969chriscraftroamer46

The Roamer fuel system is coming along nicely. I consider this to be a priority item in my quest to get the boat out of the tent and launched before November 2022.

There’s a new marina manager, and they’ve significantly jacked up the cost of land storage to match the prices they charge at all of the other marinas in the area that they manage. It stinks of monopoly price fixing, especially given the level of service provided at my particular marina (the yard toilet bowl was literally BLACK and coated with…residue…and I’ve had to contribute soap because they provided none for months), but regardless, just as a practical matter I need to get the boat back in the water and closer to home. So being able to fire up the engines and leave Deale, Maryland, in October is my primary focus right now.

The fuel filters and on-engine hoses and fittings are installed, as is the fuel supply distribution manifold, and the fuel gauge is working. So next I started bending tubes to connect the bulkhead fuel return fittings to the on-engine hoses.

This short section of tubing connects the engine room bulkhead fitting to a small fuel return manifold

A little Tefgel to lubricate the Swagelok fitting threads

The tubing is loosely fitted in place

The fuel return manifold is much simpler than the supply side

Under normal conditions, each engine draws from and returns to its respective tank: stbd to stbd, port to port. But if I get a fuel problem in one tank and need to run both engines off the other, I’ll need to direct the return fuel flow to the tank I’m drawing from.

It would have been tidier to have both manifolds on the same panel, but I chose not to because of space limitations and system efficiency. Putting the return manifold on the supply manifold support panel would have required additional 90° bends, and each one reportedly adds the equivalent of 15′ worth of straight tubing friction. A tidier appearance would have required the equivalent of 60 additional feet worth of friction, and I don’t think it’s worth it.

What else could I do???

Putting the return manifold so close to the bulkhead fittings was one of those “all things considered, this is the best spot” kind of decisions. But the ER floorboard support 6061 aluminum angle was perfectly in the way. I didn’t want to cut cut the floor support and weld in a brace for it somewhere else. So instead I made a relatively big loop in the tubing so it goes under the floorboard support with a 90° bend to the bulkhead fitting.

With the start and end points done, I bent tubing to connect them

As a rank amateur, I’ve developed great respect for professional tubing benders

So, you’ve got to connect A to B, but the tubing has to take a 110° bend to the left, go 11 inches forward before bending precisely 12° to match the bulkhead and then go 17-1/4″ outboard before turning 90° forward for 58″, then 45° up and terminate in 7″…oh, and that’s all in one relatively short run of 304 stainless tubing…easy peasy.

HA! NOT!

In a stunning development, it fit perfectly the first time!

Pro tip: don’t get cocky when amateurs are bending stainless tubing.

The last 45° bend to meet the starboard main engine return line

BOOM!

I used expanded PVC again to stand the return lines off the engine stringer and p-clamps to hold it in place. Stainless screws and their corresponding drilled and tapped holes were coated with TefGel before installation. The starboard side return line is a wrap.

The port side was a slightly longer run

I had to bend it in the salon because there wasn’t enough room in the engine room.

Each additional bend significantly increases the risk that I’ll screw up and turn the whole thing into scrap

Quality tools make the job easier to get some things right

When the Swagelok bender indicates the tube is bent to 90°, you can take it to the bank. But the trick is, you have to over-bend a wee bit so the tubing settles in at 90°. Which only added to my appreciation for professional tubing benders.