Greeting.

I am considering purchasing a Robert Tucker 51 (1987 steel). My most
pressing concern is the holding tanks. They are made out of mild steel
and there are no 'view ports'. There are four of them, each a 1000
litres. Two for water and two for deisel. The current owner does not
know how the tanks were originally treated. Is also seems that the hull
makes up part of the tanks (I have seen them described as wing tanks).
If visual inspection is not possible, is there any other method of
accessing the state of the tanks?

If the tanks turned out to be corroded then what are my repair options?

I have been told that I can have the hull thickness measured. This
seems to involve only spot measurements every meter or so. Would this
be sufficient to assess a weakness in the hull caused by corrosion on
the inside of the tanks? Is there a better method?

Any advice would be appreciated.

Regards
Warren