> Are the 4u rack boats "shallow" like the 18u and 12u boats?
I assume they are the same boats as the cabinet 4-space boats only
with rack ears instead of wood and no "legs" and handle. In that case
the ones with psu are 85mm and the ones without are about 65mm. The
psu type has card connector, power inlet and mains switch on top of
the boat so you need some free space above it.
Johan