Sorry for the late reply, but it was only last week when I was able to visit my Dad who has a photocopy of the 1911 Carson catalogue that I could confirm that Carson did make marine engines in single, compound and triple cylinder arrangements. So, it looks as though you may have examples of the first two.
I now have a scan of the catalogue, but the pages are all mixed up and in different orientations. I will try to extract, crop, orient and collate the relevant pages and post them here - might take another few days.
Andy
