1990 Viking 50 MY fuel tanks

Have you called Viking with the hull number?

Viking Yacht Company
PO Box 308 New Gretna, NJ 08224
Phone: 609-296-6000
Fax: 609-296-3956
Customer Service E-mail: customerservice@****************

I thought Lazzara only built the bigger boats like 60+. Then I hate to say that you re out of luck as they went out of business about 10 years ago. The new Lazzara Yachts is building in Turkey, with no real link to the old company except for one of the son

that said the tanks should be easy to find start in the ER and follow the fuel lines. Material will be obvious. On the bigger boats Lazzara used fiberglass keel tanks

I would think their name was on it, they would have some specifications on it.
I'd call them back and and press this this if it's important to you.
OTOH,
There are catalogues that surveyors and some better brokers use that have most of these specs in. Maybe tap on your purchase surveyor for this data.

Hang on,,,,, Your a broker, surveyor or wanna-be?

True. Even though they didn’t built their MY until recently you d think they have some data since they slapped their name and sold them.