RexReed . . . I had a 1991 Formula 242 . . . the water tank for the sink was located at the front of the V-berth, there was a panel beneath the V-berth cushion where you could access the tank. There was not a fill line leading to the deck IIRC.
The sink itself was a manual pump faucet that drew water from the tank.. Primitive by today's standards.
Post up some pictures of the 272 when you have a chance. I believe the 1987 models came with Alpha One drives, since the Bravo drives were not introduced until the following year (1988)