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sailorboy1 · 19-04-2016, 06:44

I'm installing a diesel generator in my boat. The generator is metric and the seawater cooling connections are too large for 1/2" hose, but a little loose for 5/8". Is there any "better" method for sealing them than just tight double clamps?

**skipmac** · 19-04-2016, 07:07

Have you tried ordering metric hose from Europe?

How tight is the 1/2" hose when you try to fit it onto the generator hose barb? If not extremely tight have your tried heating the end of the hose to soften it and stretch it over the barb?

I had the same problem with some of my plumbing. Not due to metric, just the differences between different brands of hose and different types of hose. Got out my heat gun, warmed up the hose and it slipped right on.

**a64pilot** · 19-04-2016, 07:16

9/16 hose ought to be available.
Do you know what metric hose is called for?

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**Dockhead** · 19-04-2016, 08:37

Quote:

Originally Posted by sailorboy1

I'm installing a diesel generator in my boat. The generator is metric and the seawater cooling connections are too large for 1/2" hose, but a little loose for 5/8". Is there any "better" method for sealing them than just tight double clamps?

This sounds very strange to me. 1/2" nominal i.d. hose is the same as 13mm nominal metric hose and should be interchangeable. The next size up is 16mm which is 5/8". There isn't a standard size between those two.

Cheechako · 19-04-2016, 08:45

Fittings not compatible with hose is a common issue... metric or not. I would try to find the right hose. But if you cant, I would likely wrap the fitting with that self amalgamating tape. The stuff is tough as nails once on. You just stretch it as you wrap and it seals to itself. You have to cut it off. It's sold as commercial electrical tape. It's also not slippery and grips well.

Zach · 19-04-2016, 09:39

Does the fitting have a bulb shape to the end.

I would break out the calipers and verify the size, is not in fact 1/2 inch behind the bulb... and see where you end up, particularly if you have a heavy wall thickness to work with.

I've had to take sandpaper to cooling pump hose fittings before on account of the shape of that edge, if they won't take wire re-inforced hose. Sometimes if they are delivered "As cast" and not machined, you run into that...

Cheers,

Zach

sailorboy1 · 19-04-2016, 09:44

Quote:

Originally Posted by skipmac

Have you tried ordering metric hose from Europe?

Dam why didn't I think of that (plus the anti-siphon valve)

But would still need to connect the hose to the boat and have same problem and that would be the only connection that is always below the waterline.

sailorboy1 · 19-04-2016, 09:50

Quote:

Originally Posted by Dockhead

This sounds very strange to me. 1/2" nominal i.d. hose is the same as 13mm nominal metric hose and should be interchangeable. The next size up is 16mm which is 5/8". There isn't a standard size between those two.

The connections are listed as 16-mm so the 5/8" should be slightly tight, but it is loose. But it matters little as it is what it is.

**a64pilot** · 19-04-2016, 10:10

I'd be leery of the tape for a long term solution, But I'd do it to finish the install.
I think I'd go as far as buying fittings and having them machined down to fit a standard hose. You want to be able to buy hose "out there" if you need to.
I looked and 9/16 hose is available, but it's not going to be "out there" it would be a special order or something you would carry forever.

sailorboy1 · 19-04-2016, 10:20

Quote:

Originally Posted by a64pilot

I think I'd go as far as buying fittings and having them machined down to fit a standard hose.

You wouldn't I bet if it met pulling the generator back out of the boat and taking the enclosure apart to get to the fittings

Sailmonkey · 19-04-2016, 10:26

I've run silicone heater hose over metric fittings for water when I couldn't get anything else to work. It's stretchy enough to seal correctly, an it's nylon reinforced, so I'm comfortable with it below the waterline.

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**a64pilot** · 19-04-2016, 10:41

Quote:

Originally Posted by sailorboy1

You wouldn't I bet if it met pulling the generator back out of the boat and taking the enclosure apart to get to the fittings

Your right, I wouldn't.
Your fittings aren't in the enclosure, with hose on either end, so that take off the hoses, remove locking nut and fitting is removed?

**skipmac** · 19-04-2016, 13:19

I was installing some new Groco 1.5" hose fititngs to my through hulls, sink drains and a couple of T-fittings. Bought a couple of types of new 1.5" hose for the various connections. I think I was able to get some hose on one or two of 10-12 fittings, even after lubing the hose barbs with various goops, using force and even tools. These were all supposedly 1.5" and compatible.

Got out the heat gun and all fit together easily.

It may just be stiff hose vs fitting, even if they are the "same" size.