What's this thing and why is it in my head?

[Stephen_MO]

Maybe it is an "earworm" I have it on good authority that those can really get stuck in your head.

[Nicholson58]

Originally Posted by HopCar

Looks like a small air compressor to me. If it was some kind of liquid pump it would have two hoses connected to it.

I agree. Vacuum pump or more likely a compressor. Air horns?

[Nicholson58]

Originally Posted by riksf

Definitely an air pump (and it still runs!). The fitting on the end of the hose looks like it fits a standard Schrader tire valve. The wires ran to an unlabeled toggle switch (which was so corroded it fell apart when I touched it) taped in a cabinet above, which in turn ran to the cabin lighting circuit. Why it was there I may never know, but it resides in the trash now.

Look at the hose end. Definitely air compressor. That’s a quick connect for a bicycle valve.

[Kelkara]

For inflatable fenders?

[nofacey]

By any chance is there a pressure kerosene stove onboard?
- looks like a bit of kit that would be useful for that.

[sinnerman]

It is an old version of the "flux capacitor" to enable the boat to travel through time...

[Fidsplice]

Compressor to pump out by pressuring the tank in the days before pump out stations were common?

[sinnerman]

If the boat had a pressurized alcohol stove, it could be used to supply the pressure to the fuel tank.

My boat came with a deactivated alcohol stove and it had a tire pressure stem on the fuel tank to pump up the pressure.


Cheers.

[Dreaming Yachtsman]

Originally Posted by garyfdl

You threw it away?!?! That's a 'good' piece of jun... er, stuff!

Once seen on a Tee shirt in a shop at Pike Place Market in Seattle:

Junk is Stuff you want to get rid of.
Stuff is Junk you want to keep.

Accompanied by a stick figure of a guy carrying a box.

[GrowleyMonster]

For pumping up the pressure tank in a pressurized potable water system. It keeps the electric pump from cycling so much.

[garyfdl]

Originally Posted by Dreaming Yachtsman

Once seen on a Tee shirt in a shop at Pike Place Market in Seattle:

Junk is Stuff you want to get rid of.
Stuff is Junk you want to keep.

Accompanied by a stick figure of a guy carrying a box.

[garyfdl]

Originally Posted by GrowleyMonster

For pumping up the pressure tank in a pressurized potable water system. It keeps the electric pump from cycling so much.

If you need to keep pumping up the pressure tank? It needs to be replaced.

Unless your 'yacht' is the size of Jeff Bezos' boat, a potable water system with a pressure tank is probably overkill.

In light of the location and short hose, I think the correct answer was it was used with the diesel heater.

[pbmaise]

To atomize diesel fuel you can use high pressure and tiny nozzle.....but this tends to clog.

Another approach is to use compressed air.

ITR Marine Heater has a very different nozzle and atomization scheme than an Espar or any other. The nozzle isn't a tiny little hole as pressurization across the nozzle is not used to atomize the fuel. Diesel is sent to the nozzle at zero pressure, an air jet from the compressor blows across it to atomize the fuel. Still has a flame sensor and igniter though.

[Lodesman]

Is there anything there or in the "spare parts that came with the boat" with a schrader valve on it? Is there a switch at the other end of the wires, that's labelled? I assume a PO had a reason for putting a pump there, other than solely to confuse future owners. Perhaps it was to blow out the FW lines for winterization?

[Orion Jim]

Originally Posted by garyfdl

Unless your 'yacht' is the size of Jeff Bezos' boat, a potable water system with a pressure tank is probably overkill.

Pressure hot water, gimballed stoves, standing headroom, self tailing winches, manual windlass, wind vane self steering, furling headsails…just to name a few. Having worked my way up from daysailers in the 60’s, it’s what makes cruising pleasurable. We all have the choice to abstain or take full advantage.