Fuel Tank Inspection Port

[MrBreeze]

Howdy,

I am looking at a Gulfstar 43 Ketch which has a fuel tank for diesel that is all fiberglass and integral with the hull. The boat is 31 years old and has probably 31 years of "crud" at the bottom of the tank. As far as I can tell, there does not appear to be a port that would allow access to clean the "crud" out. Dose anyone have any ideas on how to go about installing such a port and what type should be used? Recoomendations on bio-cides and additives are also welcomed.

Thanks!
Rick