Fuel tank in a 2400 SCR, not an easy job.
Pull the engine, cut out bulkhead between tank and engine. Remove floor in aft cabin to access the tanks hold downs. Remove tank and install new one in a bedding. Replace aft cabin floor and bulkhead. Install engine and aligne it before installing drive.
You may want to look a the Bayliner Owners Club for this topic as it is very common for them and there are very detailed threads with lots of pictures.
1997 2400 SCR
5.7 Vortec / Bravo 2