I drink on board to calm down.

There will be no sermon here. But we will say two things plainly.

First: alcohol lowers your reaction time, your judgement and your perception of risk, precisely at the moment you need all three. On board you are responsible, often for other people. That cannot be argued away.

Second: if you notice that you need it in order to be calm, then calm is no longer the subject. At that point it is no longer a case for mental training, it is one for addiction counselling. That exists everywhere, it costs nothing, and the people there do this every day.

Asking the question at all is, incidentally, the hardest part. The rest is easier.