Another quality item here - and the 'attraction' to storms could be very subtle. It would be those captains who are a little more tolerant of bad weather that would be in greater danger, for - magic or no - a storm takes time to come close.
It may be subtle enough that the locals who use these sails simply build sturdier ships over time - shipwrights who built too frail ships would be eventually driven out.
Originally used to combat poachers, this trap consists of a blunderbuss (or crossbow, if you want to stay in period) on a swivel with several triplines. When tripped, the weapon will swing in line with the activated tripwire and fire down it. Go to Comment