......I think the 1922 record was broken by the CC Packard that topped out at 45 mph or so (The boat is in Jacksonville, FLA, but I will have to google to find it)

Edit: My friends' was the record for a six cyl. 20 ft. apparently. It looks like they had 12 cyl. CC Packards around 1925 that made 500 hp and topped out at 55-60 but I don't know what lenghts.