What are these pipes?

[PaulZeeders]

Hi
We have a steel yacht that has a pipe that appears to link the rear of the keel to the rudder sked. The red pipe in the attached photos links the keel to the rudder sked but goes nowhere else. What are these pipes for?

Many thanks Paul

[PaulZeeders]

Sorry left photo is upside down, these pipes go into the keel

[glenn.225]

Keel cooler for something, engine, fridge???


Maybe vent to extract mist air so it doesn't rust from the inside.


Just guesses.

[Ballsnall]

Cooling system is the most likely reason. Any liquid in there?

[hpeer]

That appears odd. I believe I am not seeing something correctly.

You are concerned about the red and black hoses?

It looks like there is a T fitting where the red and black hoses connect together?

First are both pictures of the same END of these hoses? Or are they showing one end to the keel and the other end to the skeg?

The simple and obvious answer is a cooler, but then one end would he going to some equipment, like the engine. If these are simply connecting the keel to the skeg, well that is interesting.

How is your engine cooled? Normally you would have sea water circulating and coming out the exhaust. Or do you have a dry stack exhaust?

Some vital bit if info is missing here.

[PaulZeeders]

Hi
The photos are of each end of the red pipe. The engine has a heat exchanger with sea water discharging into the exhaust bend. The steel pipe fitting going into the sked has been specially made as though there is an inner and outer pipe going down into the skeg. I am struggling to understand why you would have this set up. There is a nut welded at the top which I beleive is for screwing the fitting down.

[Bowdrie]

Whatever the purpose, that little black hose off of the tee fitting appears completely collapsed/kinked.

[MicHughV]

I'm going to go out on a limb here.....any chance there is fuel tank in the keel ??

[PaulZeeders]

Yes there is a fuel tank in the keel. The rear inspection port for the tank is approx a metre forward of the 2 pipes that go into the keel.

[MicHughV]

well, if there is a fuel tank in there, it could either be a fuel return line from the main engine or a vent line....
I'd trace the line to see where it goes.....if it goes back to the engine, it is likely a fuel return line.....if it goes towards the hull, it's likely a tank vent line...

[PaulZeeders]

The red pipe just connects the keel to the rudder sked. All the fuel pipes are further forward in the inspection hatch of the tank.

[MicHughV]

My first boat was a steel boat.

Also with a skeg hung rudder....when you say sked, I'm assuming you mean skeg.

My skeg was hollow and had nothing but air inside, but I know some steel boat builders that filled the skeg with oil to prevent interior corrosion, so those pipes could have something to do with that. You would need one pipe as the fill pipe and the other as a vent.

[hpeer]

Paul,

Easy to see why you are struggling. This is a real head scratcher.

Many things baffle me. I can see why you think the skeg fitting may have an inner and outer run. But that would imply that there are 2 feeds, but the red and black hoses seem to go to a single T. And the red and black hose seems very intentional, as if to indicate 2 different runs.

OK, I am going to suggest something very weird.

I believe it is POSSIBLE that there are 2 pipes/hoses all the way through. That inside the Red hose is a very small copper (?) tube. The copper tube runs inside the red hose. The copper tube then is split from the red hose in the T and enters the keel and skeg through the black hose.

To go much further on a limb, a really wild suggestion, just to stimulate thought. The inner copper tube connects the keel fuel tank to the skeg void. The inner copper pipe goes from the bottom of the main fuel tank to the bottom of the skeg tank. The outer hose transmits air pressure (or suction) to either force fuel into the skeg, or force fuel out of the skeg. In short the skeg is a secondary fuel tank.

I see some problems with this outlandish theory. But it does satisfy some features.

It is also possible that there is a cable or wire inside the red hose. But I can’t think of a reason for that.

I still think there is some other clue to this arrangement.

It is very weird.

[hpeer]

Originally Posted by MicHughV

My first boat was a steel boat.

Also with a skeg hung rudder....when you say sked, I'm assuming you mean skeg.

My skeg was hollow and had nothing but air inside, but I know some steel boat builders that filled the skeg with oil to prevent interior corrosion, so those pipes could have something to do with that. You would need one pipe as the fill pipe and the other as a vent.

My rudders are oil filled, no vent.

The small boat has an empty skeg just as yours. I have thought of filling it with oil.

My big boat had a weird void near the end of the keel that caught water and had rusted badly. We made a plate to go over it and welded it in. The plate had a hole/screw so that I could film this void with oil. It was a small void, a bit under a quart of oil IIRC.

I am not real happy with the explanation I gave in the post above. Some things still don’t make sense. But I do think you and I are working along similar lines.

If he finds a mystery air pump or air fitting that would be interesting.

[MicHughV]

My steel boat had a "fin keel" arrangement. There were 3 frames that extended down into the keel void, making for 4 compartments.
Plans called for the first three voids (compartments) to be be filled with ballast, which in my case was a combo of steel punchings and lead.

The last void at the trailing edge of the keel was empty. This posed a problem for me, as I could not get down in there to sandblast and paint it.
So I filled it with concrete.
On the outside bottom edge of the keel I drilled a small 1/4" hole to allow water from the concrete to drain, which over a period of weeks did, then I welded the hole shut.

This is all neither here nor there, but most steel boats are home built, and I suspect the OP's boat has some quirks that the builder addressed in his own way.

Not being able to see the boat is also a problem.

It's always difficult to assess a problem from a few pics posted here and becomes a bit of a guessing game in the hopes that something said here my provide a clue or solution.

The black hose looks crimped to me, so it's purpose is ????