are fitted with two brush assemblies on the silver-alloy
auxiliary to verif y operation of the controlling cell and
serves as a backup if failure of the primary cell occurs.
Reference electrodes are generally located on each
Rudder Ground.-- Rudders and stabilizers are
side of the hull, about halfway between the anode
grounded by brazing a braided, tinned-copper
sites. Reference electrodes are usually replaced
grounding strap, at least 1 1/2 inches wide, between
approximately every 10 to 12 years.
the rudder stock and the hull. To permit full rotation
Stuffing Tube.-- Stuffing tubes are required to
of the rudder stock from port to starboard, a large loop
insulate the electrical wires that pass through the hull
is required in the ground strap.
to anodes or reference electrodes.
Dielectric Shield.-- The dielectric shield prevents
Shaft Grounding Assembly.-- The shaft
shorting of the anode current to the hull and aids in
grounding assembly (fig. 11-13) consists of a
wider current distribution. The dielectric shield is
silver-alloy band, ring-fitted on the propeller shaft. It
applied as a thick coating around each anode. It
is electrically bonded to the shaft and is usually
consists of a high-solids epoxy with a high-dielectric
located in the shaft alley. Silver-graphite brushes ride
on the hard silver surface of the bands, electrically
OPERATION.-- The requirements for operating
connecting the rotating propeller shaft to the hull. This
the ICCP system on ships is provided in the
assembly is necessary to permit the anode current that
manufacturer's technical manual. The system should
flows through the water to enter the propeller blades
be operated at all times, except during diving
and return to the hull. A shaft grounding assembly is
operations, equipment repair, planned maintenance,
provided for each shaft. Ships of earner size or larger
Figure 11-13.--Shaft grounding assembly.