……or ordinary household light grey undercoat.
Having just dived in to add my pennies worth of sage advice I can’t remember what your final hull colour was…however it will need some undercoat so a tin of Halfords best grey primer will do, and can be used for the top as well!
There is a lot of talk about “the right grey” for warships, but within a broad range of greys, anything is acceptable as grey is one of those colours most susceptible to the prevailing light conditions, and how light or dark it is.
Ashley