I have a very vivid memory of sitting tight in Unst while another 'braver' pair of chaps went off in their 61 on a not so fine morning. Their assurance that they could get rid of any ice by hovering over the sea didn't really convince me that either of them, experienced as they were, really understood what was about to happen.
About 30 minutes later they re-entered the crew room, where I had cosily sat with a fresh cup of caffeine. Both were grey and quite jittery. I asked a simple question.
"If hovering over the sea will get rid of ice building up on your blades, how come ships accrete ice like a lollipop in arctic waters?"