Re: Anyone recall 1960s black tarry marine glue product?
I also thought of the Norfolk marine product, but you call it, in the op, '....glue product'
Do you mean glue or a tar based varnish?... there's still available a bitumen (?) based black tar here, mid Portugal, even with due adherence to Euro regs, used typically on freshwater flat bottom four plank skiffs, but it ain't glue.
I could find if its available commercially, but I'm guessing its a home brew of roofing sealant and black bitumen, and if it is glue you want I don't think I can help. good luck.
Bilious, choleric, sanguine and phlegmatic