More than likely because the 'Buffer' (Chief Bosuns Mate) has told him to get up inside the Hawsepipe and paint it - despite it being quite dangerous with 30,000 ton of ship swinging off the end of that cable!!
I can recall before )Health and Safety regulation), as a very young skinny OD - being sent over the bows (in a Bosuns chair), whilst we were underway in HMS Achilles, I was first told to hold at deck edge level, whilst they put the anchor 'cock-a-bill' - then told to lower away and pull myself in towards the Hawsepipe using the cable.....so I could get a 'long-tom' dunked in pussers grey up the Hawsepipe, this was just before we met HMY Britannia (and the Queen).
I assumed then that it was OK - as I didn't know any better, on reflection I could have quite easily lost some fingers or even worse.
I think the Achilles you seen in Cochin was the wartime cruiser of the battle of the River Plate fame (5th ship to carry the name), the Achilles I mentioned was the 6th RN ship of that name and wasn't built until 6 years after your Cochin encounter.