The chart linked to by DaveRo gives depths in metres.

this song, taken seriously, would be a danger to navigation. "55 fathoms (say 100 to 110 metres) with a fine sandy bottom" - where would that put you?

If you are entering the Channel from the west/south-west and you are sounding for depth at 100 metres and you heave to when you get that depth then, according to that linked Chart of the Channel then the one thing you do know is that you are safe as you will have stopped short to the west of both Ushant and Bishop's Rock in the Scilly Isles.

Again looking at the chart if the wind was from the South-West when you hove-to that would mean that it would be blowing from the perfect direction for a square-rigged ship to run before the wind straight up the Channel. A wind that would put you on a lee-shore would be blowing from the North to North-West (Blowing you onto the coast of France) or from the South to South-East (Blowing you onto the coast of Cornwall).