Thanks for the great work Steven! I take it youíve got a good engineering library nearby.
Iím satisfied that this pipe is bring high pressure water from the ash hoist control valve. Maybe they found that some of the lumps of ash scattered in the wind or that the final discharge left a dirt stain down the side of the ship. Using this pipe to run a spray nozzle over the ash outlet would be a way to stop that. I Googled Mr See and found lots of period references but none mentioned this detail so Iím only guessing so far.