On the PSX version, while leaving the Venice section one, where you have
to race the boat to get through the timed doors. I found if you leave
the boat next to the exit doors, they don't close when the timer
expires.
After leaving the boat next to the exit doors, swim back to the switch
the starts the timer. Push the button, and swim back to the exit doors.
They will not have closed. DO NOT GET BACK INTO BOAT(the doors will
close),swim/wade through the opening. You will appear in the next
section on the boat you left behind.
Jerry T. Freeman
Seth Lachner
PS We are checking on the PC version for the same bug.
Written by Jerry T. Freeman and Seth Lachner. Preserved here with the author credited. Original source: The Spoiler.