Surreptitious masturbation?

yourself or a colleague?

This

The Marine Accident Investigation Branch web site.  Lots of reports that make you very happy you're not a fisherman or working on a big cargo ship.

Sails - are you contributing to MAIB's work?

Nope never been involved in an incident that they've investigated.  Been to a fascinating talk though from one of their investigators about their work.

And were you surreptitiously masturbating?

sailo - we should chat over a pint.