The article doesn't mention the reason why ships need this scrubbing of barnacles and other marine growth: It radically improves fuel economy.

It's a 1-2 day job per ship depending on size of the diving crew.

22 year old single me would have enjoyed this little adventure.

Automated barnacle carwash coin! Anyone?

Over 50s me would love to do this. Though perhaps not on the schedule this work demands.