having played a lot of this puzzle on https://www.puzzle-battleships.com/ ... I'd love a couple QoL improvements, one from there and one to be better than that one

- counters for columns/rows would be a nice idea to steal

- inverse control (so, lmb for ship) would help with not interfering with default behaviour, for people switching to/from different puzzles

Also ship helper really should come with each type on its own line - your listing is harder to parse than on that website