Mystery Fitting. Need help Identifying it.

[Osprey69]

I have never seen this before. The fitting beneath the diesel fill. Cannot be unscrewed and it has no visible vents or holes.

Anybody know what it is?

Thanks in advance.

[CharlieO.]

Looks like a hydraulic line fitting.

Could be a quick connect for something.

[High Wire]

Can you look behind it?

[Osprey69]

Charlie -Nothing moves.

High - No.

Thanks.

I have been around boats for over 50 years (OK...mostly sailboats) and I have never seen one.

[CharlieO.]

It would move when you push The appropriate hose fitting onto the receptacle. Usually for hydraulics there would be two, a supply and return.

Only that nipple in the center will move to allow flow once hooked up.

You haven't found any mystery hose?

My other thought is maybe it is plumbed into your fuel tank due to the location near your fill.

[TowLou]

Sure looks like a fuel or pressure fitting. What is behind it? What kind of fittings and plumbing?

[Circumnavigator]

It looks like a hydraulic quick disconnect, see https://www.mcmaster.com/95825K23/


Jim

[Osprey69]

Thank you Circumnavigator! That's got to be it.

Which leads me to my next question.

Why a hydraulic fitting?

Where the fuel fill hose enter into the engine room it is impossible to contort my 6' 4"ness to tend a few things including solving this riddle.

Need to hire a smart kid like I have done in the past.

[diver dave]

a broken one of these? Is a upper antenna support possible in the given position?

[RT Firefly]

Greetings,
Mr. O. Take out the three screws and try to gently pull the fitting out. There may be enough slack to examine the backside and lead you to a less speculative answer. Of course, re-bed with butyl tape.

[IRENE]

I will be the outlier and say it is for a washdown hose, either plumbed into the fresh water system OR with its own pump. I seem to recall seeing these in the (way) past. I will try to locate an example online.

[IRENE]

Sam 's Marine Inventory

[IRENE]

Maybe dockside water connection, instead of washdown. I think Hatteras used them.

[Osprey69]

DD...not broken. Complete cast.

RT...that's my next move.

Irene...not a dockside water connection. That is elsewhere.

Thanks to all for your input.

[KnotYet]

In my industry we use those fittings on our propane connections and hoses.
My logical brain would want to group flammables plumbing near one another and
away from water connections which makes me want it to be fuel, oil or propane.

If the installation adheres to typical practice, then that fitting would 'receive' the
pressurized fluid. Does your boat have hydraulic powered windlass or thruster(s)?

[twistedtree]

I agree that it's a hydraulic quick connect, or at least the male half. But it's probably not used for hydraulics unless there is also a return fitting somewhere. Possibilities include:


1) A fuel transfer port for moving fuel from an on-deck badder into the main tank(s).


2) Quick connect for a built-in pressure washer. These run at a pretty good pressure, so the pressure rating of a hydraulic disconnect would make sense.


It seems overkill for a water fill or lower pressure washdown.

[IRENE]

Another source for the female half:

https://www.boatownerswarehouse.com/...t_p/106870.htm

[IRENE]

Here are a couple of examples on a 54 Hatteras from the 1990s:

[chriscritchett]

I’m guessing SW of FW wash down connection, unless you have those elsewhere. Yes, overkill for a low-pressure connection, but also convenient.

[CharlieO.]

Nice Jeff, in your pics it's labeled as fresh water washdown.