Built for $5,250 for MP Pembroke (herreshoff.info)
Herreshoff design no. 670s
The following history is courtesy of the Rochester Yacht Club
The first P Class boat, rating 31 feet under the Universal Rule, was the Herreshoff sloop Seneca which successfully defended the Canada’s Cup for the Rochester Yacht Club(RYC) in 1907. Seneca was bought from its RYC owner by Commodore Jarvis of RCYC in 1911 and became the first of a strong group of P’s in the Toronto area. In 1919 RCYC appropriated the sum of $10,000 to purchase additional P Boats for resale to members and four were brought to Lake Ontario from the Atlantic seaboard, raising the total fleet to eight.
More here on the part Seneca played in the Canada’s Cup Race and her restoration.