Having worked in the Caledon Shipyard in Dundee,in the early 70,s as a paint sprayer,i can confirm that the use of Red Oxide paint,that contained Lead,was used to paint hulls,the reasoning behind this,was that it acted as a rust deterrant and a barnacle deterrant,as it contained high levels of Lead and fungicidal,which apparently barnacles did,t like,The inside of all the boats I worked on also got Red Oxide as the base primer,Then Grey primer,then white Cellulose primer then the top coat, of what ever colour was required,
All of the above paints are now prohibited,under Health & Safety,although you can still get Red Oxide,and the other primers,but they do not contain lead,
Wullie