You need to think around 1976. I'm sure the caraboat or whatever name you'd like to give it was under construction 1976 to 1978 (when we were building Miss Dawn on Jimmys site Peter, and when SLP were in Leo Robinsons blasting and causing all the problems with rust contaminated blast material landing on the boats and staining them).
Jimmy was putting it together as a spare time fill in project when the fleet allowed so my guess is either 1978 or 1979 launch. It looked like a pick up truck though!