Portapotties
Portapotties require no plumbing; they may
or may not have a reservoir for flush water. Bowl contents
drain by gravity into a removable tank which is carried off
the boat and dumped, although some larger models can be fitted
for pumpout. Very little water is used in the operation. Capacity
is 2-5 gallons.
The Head (Marine Toilet)
Manual pump heads are just what the
name implies: you pump water in and out of the bowl manually.
They are designed to use "raw" (sea, lake or river)
water for flushing. The amount of flush water can be controlled
to some extent by how much you pump. The best known are manufactured
by Blakes & Taylors and Microphor Inc. It's possible to
add an electric motor (typically 12v DC current) to some models;
the motor simply replaces your arm in activating the pump.
Electric macerating heads are only a little more complex than
a manual head. They are typically designed to use raw water.
An impeller pump replaces the piston type found in manual
heads, and there is also a discharge pump. Between the two
is a device called a macerator that is not totally unlike
a blender or a garbage disposal, it purees solid waste &
paper. Like a garbage disposal, a macerating head needs a
lot of water, typically 1 to 3 gallons each time it's flushed,
or it will burn out.
