Iain_S

If there is oil on the Bendix, it collects dust/crap which eventually stops the gear moving forwards. Possibly more relevant to road vehicles, when the main source of dust is the clutch.

Maybe where a prop was placed when dry docked?

Not before replying to Nick. We do seem to be in agreement, though

They may be making themselves attractive to females ...

That's surprising. I used a powertwist belt on Gamebird due to the very limited adjustment available, and run it slacker than a standard belt would be. No slipping!

Possibly Norse, thwaite

I'd put that percentage a LOT higher!

If it's a Foul Water drain, then no problem.

Doesn't really matter, although the blurb under your picture gives the reasons. The lower pump can be a small capacity one, which will draw less current when running and will probably be able to get more water out than a larger one. The second, higher, pump can be a bigger one, as it will only come on in an emergency, such as failure of, or a leak sufficient to overwhelm, the first one.

Our "local" pump out used to pump straight into the Foul Water drain. However, the flow was sufficient to pull the water out of the "U" bends in the adjoining (downstream) toilet and laundry block. It now empties into a tank. Personally, I don't see why the tank can't be emptied slowly into the drain, but the effluent is removed by tanker. ... and sometimes by the emptying of "compost" loos.