I know this might not be the best of ideas but...
Seeing how the plank is just there and not really used for what it is intended.
What if anytime you killed a pirate on your ship you had the ability to do a finishing move? (yes similar to call of duty)
And one of these is the walk the plank?
Basically creating an animation of you pushing the foe with the sword over the plank and then once he falls off a shark takes him under, then the animation disappears.
Take in mind this would only be the animation itself not your actual character but your character would be frozen while this is happening and it would only be around 2 seconds or so, it could also be cancelled at any time should you need to for whatever reason.
