I am running a Win 7 64bit machine. I just started playing Port Royale this weekend and was able to play for several hours before the first crash. Now it seems to crash sooner and sooner. Last time, I hadn't made it 5 minutes from the load screen before it crashed. I don't get an error message or anything. One second I am sailing along and the next, it crashes and I am back at my desk top. Any ideas?

I had the same problem and stopped playing PR1 because of that but then spotted someone posting a solution in a forum. Never got around to trying those as I took up X3 instead. Sadly do not remember where this was posted but looking now. First place to look is here on GOG ;-)

GOGs support page: https://www.gog.com/support/port_royale

here was one possible solution:
https://www.gog.com/forum/port_royale_series/got_port_royale_to_work_on_my_windows_7