This sounds like a Mariner or Rhodes 19. Length: 19' 2", Beam: 7' 0", Draft: 3' 3" (keel version).
The Mariner has a small cabin, it will have 2 berths and a small galley with no aft bulkhead on the cabin if the boat is the original Mariner model, if it is a Mariner 2+2, it will have a V-berth and 2 quarterberths (bunks that extend under the cockpit), a bulkhead at the aft end of the cockpit with a hatchway, the cockpit will have drains and be self-bailing. A later Mariner (1975-78) will have a smaller cabin house, but the same basic layout as the 2+2.
The Rhodes 19 is the daysailing version of the Mariner (well, actually..the Mariner is the cabin version of the R19, the R19 was produced 5 years or more before the Mariner) and has a Day Sailer- style cuddy.
Both boats were offered in fixed-keel and CB versions, The R19 had a "kicker-pit" molded into the aft deck to allow the outboard to be clamped to the transom, I think the early Mariners did as well. Later Mariners (2+2 and later) had the cockpit running to the stern and so the motor could be clamped right on to the transom. The sailplans for these two boats were slightly different, due to the R19 being more often used for racing, and the Mariner for family sailing.
For pictures of the R19 and Mariner, check out this website:
http://www.geocities.com/odaybrochure/ this is a 1968 O'Day brochure.
Rod Johnson, "SUNBIRD" (rjohnson24-at-juno.com)