Something isn't right with that number. 31820 is issued to a 17' CS grade HW model with open spruce gunwales and ash seats, decks and thwarts. It also had half ribs, sponsons and a keel. It was painted dark red and shipped to Vineland NJ. The ship date is not clear, but the boat was built in 1914.
I tried looking at other records 3182X, but nothing seemed to match the long decks. They seem to be longer than the 20" decks commonly put on an Otca - are they? The kingplank is interesting also.