This is a very common problem in SS2008: The amount of available RAM—that which is left in the pool to be allocated—becomes depleted as the game runs. This is because RAM that is no longer used is not always de-allocated and returned to the pool of available RAM.
Titanic is a very high-poly model and is usually the last thing to be rendered in a new scene. When the environment changes, the RAM allocated to the old environment is not completely de-allocated, so there is not enough left for Titanic.
When you enter a new environment and Titanic is missing or incomplete, immediately save the game and exit from SS2008 completely. It is also a good idea to restart your computer as well. This should return all RAM to the pool and Titanic should be OK when you restart SS and resume the mission.
I recommend that you restart your computer just before you begin playing SS2008, and after playing for an extended period with many different environments.
A couple of additional comments:
1. Extremes also suffers from the memory leak problem, but to a lesser extent. VSTEP has eliminated reports of such problems in the specific case of Titanic through an innovative approach.
2. Your problem might be due, in part, to an unfortunate choice of log-in name. Your namesake didn’t have a lot of luck with Titanic either.