Thanks Christian for the pictures from World Naval Forums, very helpful.
Hi John
That would be fantastic if you could find out, I too came to a dead end so far other than the odd photo and old Victorian print. I really hope they didn't end up in a skip, the Yarrow collection was destroyed in WW2 in a bombing raid. I've managed to rescue some originals in the past mainly from the 60/70/80's, possibly an original Perkasa drawing- pencil lines all over with Vosper-Thornycroft stamp in the corner! Managed to save some brochures too and a book from 1930s about motor yachting.
Many thanks in advance.