....against the wingtips with neither
drag-producing mounting struts or pylons.
The 40° sweptback wing had an aspect
ratio of 5.53 and airfoil thickness ratios that varied from 11
percent at the root to 8 percent at the tip. Lift augmentation was
achieved with trailing-edge flaps and with slats located over the
outer portion of the leading edge; the slats can be seen in the
deployed position in figure 12.16. Wing spoilers were used for
roll control; elevators together with an adjustable stabilizer
were used for pitch control; and a single rudder was provided for
control about the yaw axis. Maneuvering on the water was enhanced
by hydroflaps located on both sides of the hull afterbody. When
opened individually, these flaps served as rudders for directional
control while symmetrical deployment provided braking. The
hydroflaps may be seen outlined in black in Figure 12.17.
The Seamaster crew consisted of a pilot,
copilot, navigator-minelayer, and radio armament-defense operator.
All crew quarters were pressurized and each crew member was
equipped with an ejection seat.  Armament
consisted of two remotely operated 20-mm cannons located in the
tail. The mine bay had a watertight rotary door, the outside of
which served as part of the bottom of the hull. A rack for
mounting mines or other types of stores was fastened to the inside
of the door. Rotation of the door in flight provided the means for
With a gross weight of 167 011 pounds, the
YP6M- 1was a large aircraft capable of attaining a maximum speed
of 646 miles per hour (Mach 0.86) at 5000 feet and cruised at a
speed of 540 miles per hour. Even higher performance was shown by
the P6M-2, which had engines of higher thrust than those on the
YP6M-1. From the data given in reference 200, the mission radius of the aircraft as a minelayer
seems to have been about 800 miles with a payload of 30 000 pounds
and 1350 miles for the high-altitude reconnaissance role. Ferry
range is estimated to have been about 3500 miles.
In spite of the promising characteristics
of the P6M, the Navy terminated the program in August 1959 after
12 aircraft had been constructed, including 2 prototypes that had
been lost. Shortage of funds coupled with demands of higher
priority programs no doubt played a major part in the
cancellation. The Seamaster was the last large flying boat
developed in the United States, and many viewed its demise with
regret and nostalgia.