But you'd want a wind over deck indicator to register through 360' and you'd position it at the masthead where it would be unobstructed.
The big clue is that missing sector. What and why?
What did ASDIC repeaters for depth charge/hedgehog attack look like? Were they ever fitted with one on each side of the hull allowing a bit of crossover to the "other" side? Then 30' either side of dead would need to be accurately known for running in, but not to more than a couple of degrees and other sectors to within 10 would be fine to allow you to fire abeam.