brought up to speed and clutched in to move the drum far enough in the heave-in direction to free the dog and permit it to
be disengaged The problem is aggravated by the fact that the pneumatic control system on the SMATCO winch can fail
in the "open" condition. In this event, there is no way to release the dog. Further, if the winch is not dogged, the loss of
air will lead to free-spooling and loss of the towline.
The Almon A. Johnson, Inc design automatic tow- ing machines on the ATSs, ATFs, ASRs, and ARSs have features that
make the need to operate "on the dog" rare. Moreover, their all-electric drive can be activated more quickly than a diesel
engine to relieve the load and allow the drum to be rotated or disengaged if required.
The drum-type rowing machines and winches all serve as line transport and stowage devices since the in-hauled towline
is stowed on the drum. The traction winches perform part of the line transport function, but in each case the line stowage
is in a bin below deck. The T-ATF and ARS 50 traction winches have power blocks that back-tension the line and assists
m transporting the line to the stowage bin.
The Almon A. Johnson automatic towing machine designs all have features to perform the automatic payout and heave-
in functions in response to variations m the towline tension. The ARS 50 traction winch also has features to provide
automatic payout function, however, the reclaim feature is not automatic. It requires some monitoring to control the
towline tension without gradually paying out all the line, although it does have a "cable-off" device which will secure the
5-9 NAVIGATION LIGHTS, FLOODING AND FIRE ALARMS AND BATTERY REQUIREMENTS
Refer to current COLREGs (Ref 2) for complete information on light requirements
5-9.1 NAVIGATION LIGHTS. Navigation lights, furnished under specification MIL-L-24375 (Ref. 17), have a solar switch
built in to increase battery life and meet COLREG requirements. They can be ordered by their Federal Stock Numbers
Alternatively, a single solar switch can be added to the system
5-9.2 ELECTRIC CABLE. The towing lights have a 10-foot leader wire for attachment to the batteries. If that length is
insufficient, Navy-type DMOF-4 cable is suitable for connection.
5-9.3 NAVIGATION LIGHT BATTERIES . Table 5-5 lists battery capacity, in ampere-hours, required for each side light
and the stern light, for tows of various durations. Individual batteries for each light may be used to eliminate the power
loss m long cables. Table 5-6 includes battery requirements for both continuous and intermittent 12-hour/day operations.
Batteries should be protected from electrical grounding by mounting them on non-
conductive bases or with non-conductive liners in the box.
The battery capacities listed in Table 6-5 correspond to standard Navy 12-volt lead-acid batteries These heavy-duty cells,
protected by steel containers, provide the necessary ampere-hour capacity with the smallest size and weight. Table 6-6
lists requirements for a centrally located battery.
5-9.4 PUMPING CAPACITY . For long voyages, tows should have bilge pumping equipment If the permanent bilge
pumps on the tow are inoperative, portable lightweight pumps or eductor systems should be provided. They can be
handled by the riding crew or inspection party from the tug. Tests should demonstrate that the pumps have adequate
suction lift and discharge head.