That this is even a problem is nonsense! Here is the solution: You arm your ship. You train your crew. You kill any thug who tries to seize your ship. Blow their little boat out of the water and leave them to drown. No sympathy. The thugs made their choice to live as pirates. They should live, or die, with the consequences of THEIR choice. Any other “solution” is pandering to the pirates.

After a few encounters the pirates will realize that maybe their choice isn’t a good one. Problem solved.