A slight problem

I have always loved this game, from my C64 days. On my mac book pro though the transitions from one scene to another is jittery. That is I am sailing and sail into port, game is jittery for a second. Now in town I select visit governor, game is jittery for a second. Still a great game but the jittery parts can be distracting and gets old. Hope I can find a solution, but so far havent noticed any settings that have helped.

Mstwrt about Sid Meier's Pirates!, v1.1.2