Friday, working-day after a Thursday holiday. Most people are taking the day off, but First-Mate is on a diet preparing for summer: she is saving as much annual leave as possible to have a long summer vacation.
That leaves me a day for odd-jobs on Mekicevica. One of them is checking the depth sounder, that seems to think we always have 2.5m water, even when throughout the cycle of a 3m tide in a harbour! Quick inspection reveals that there is no oil in the transducer holder. Where the oil could have been gone is a complete mystery.