LHD (SPECIFIC)
Enlisted Aviation Warfare Specialist (EAWS)
Sections 104, 105 and 106

LHD EAWS Sections: 104, 105, and 106


Section 104: Collection, Holding, and Transfer (CHT) Fundamentals

104.1 State the function of the following components: a. Sewage Collection, Holding, and Transfer (CHT) Tank - Designed to accept soil discharge from water closets and urinals and waste discharge from showers, laundries and galleys.

b. Sewage Pumps - Discharge soil and waste through transfer hoses to the pier or to overboard discharge fittings at 30-40 psi. LOCATIONS: #1 & 2 are located in Sewage Pump Room, #1 6-39-0-E. #3 & 4 are located in Sewage Pump Room, #2 6-73-0-E.

c. Comminutors - Located in the combined soil waste drain, they macerate (chop up) solids passing into the CHT tank. Both Sewage Pump Rooms #1 & 2 have a comminutor.

d. Aspirators - Provide air to the CHT tank at 12-15 psi to prevent the contents from becoming anaerobic (devoid of oxygen). Also used to keep any solids in suspension. LOCATIONS: #1 & 2 are located in Sewage Pump Room #1 6-39-0-E. #3 & 4 are located in Sewage Pump Room #2 6-73-0-E.

e. Macerators - serve the purpose of sewage pumps and comminutors combined. (i.e. chops up waste as it discharges it at 15-20 psi). LOCATION: #1 & 2 Macerators - located in the Sewage Receiving Station, 3-113-6-W.

f. Deck Discharge Connections - serve as connection fitting for sewage hoses and transfer waste from CHT tanks to pier services.

104.2 State the safety precautions associated with: a. Hydrogen Sulfide (H2S) Gas - H2S is toxic and can be explosive. H2S has been identified as the most likely gas hazard associated with decomposition of sewage in CHT tanks. At levels less than 0.2 parts per million (PPM) H2S smells like rotten eggs.

b. Sewage Spill Cleanup - Sewage should be contained to the smallest area possible. Personnel must wear protective coveralls, rubber gloves, rubber boots and a full-face shield. Sewage should be disposed of into waste drains and the affected area properly cleaned with warm water and Betadine Solution.

c. Sewage Handling - Proper protective clothing shall be worn and the utmost care shall be observed while raising and lowering sewage transfer hoses to prevent sewage spills.

104.3 State the three operating modes for the CHT system. a. Transiting Restricted Zone - the CHT system will be set up to collect and hold the discharge from soil drains only. Restricted Zone is 0-3 nautical miles.

b. In-Port - the CHT system will collect, hold and transfer to a shore facility all discharge from soil and waste drains.

c. At-Sea - outside the restricted area, the CHT system will be set up to divert discharges from both soil and waste drains overboard.


Section 105: Compressed Air Fundamentals

105.1 State the function and location of the High Pressure (HP) air compressors.

FUNCTION - The High Pressure Air Compressors (HPAC) supply 3,000 psi air throughout the ship. See 105.3 for uses. LOCATIONS: NR 1 HPAC - Forward Compressor Machinery Room (5-37-0-E). NR 2 HPAC - Aft Compressor Machinery Room (4-97-0-E).

105.2 State the function and location of the Low Pressure (LP) air compressors.

FUNCTION - The Low Pressure Air Compressors (LPAC) supply 125 psi air throughout the ship. Used for the control air system, pneumatic power, service system, and wave-guides. LOCATIONS: NR 1A, 1B, 1C - Forward Compressor Machinery Room (5-37-0-E) NR 1D - Forward Main Machinery Room (6-65-0-E) NR 2A, 2B, 2C - Aft Compressor Machinery Room (4-97-0-E) NR 2D - Aft Main Machinery Room (6-81-0-E)

105.3 Explain the uses of High Pressure (HP) Air Used onboard USS Boxer for the following purposes:

a. #1 & 2 Ship Service Diesel’s Starting Air;

b. Port & Starboard Main Shaft Inflatable Boots (in emergency);

c. Armament (Sidewinder Missile Charging);

d. Port & Starboard Aircraft Elevators;

e. Emergency air breathing flasks (JP-5 Pump room);

f. Vital air back-up (using reducers);

105.4 Describe the function of the following components: a. Priority Valve - Used to protect the control air system onboard the USS Boxer. This valve shuts as the air pressure drops to 85 psi. When this valve shuts it isolates the vital air system from the non-vital air system. All the low pressure air goes to the vital system.

b. Air Dehydrators - Used to remove moisture and impurities from ship’s low pressure air system.

c. HP to LP Reducers - Allows for the reducing of High Pressure (HP) air to Low Pressure (LP).

d. Air Receivers - Component of the system that allows for air storage.

105.5 State the function of the following systems: a. Vital Air Service Main - Provides Low Pressure (LP) air to the following: 1. ACC (Automatic Combustion Control) on #1 & 2 Boilers. 2. Electronic Dry Air. 3. Control Air for A/C Units.

b. Control Air Main - Low Pressure (LP) air to the Automatic Combustion Control air systems to #1 & 2 Boilers.

c. Electronic Dry Air - provides Low Pressure (LP) Dry air to the following: 1. AN/SPS-52C Radar 2. AN/SPS-49 (V) 5 Radar 3. AN/SPS-43A Radar 4. AN/SLQ-3 2 (V) 3 Radar 5. TAS MK 23 6. EXCOM (electronic communication wave-guides and electronic wave-guide air control panels).

d. Non Vital Service Main - Ship’s laundry, pneumatic tools, air stations, service main, message tube system (“Bunny Tubes”).


Section 106: Degaussing Fundamentals

106.1 State the purpose of the following degaussing coils: a. A-Coil - (1) one vertical loop forward to aft, main deck to 4th deck. The A-coil compensates for the induced athwartship component of the ship’s magnetic field. The coil current is maximum at equator on an E-W / W-E direction, and zero at the poles and at N-S / S-N direction. The coil power supply has a rating of 40 kW with a maximum output current of 182 amps at 220 volts DC.

b. M-Coil - (1) one Horizontal loop forward to aft, main deck. The M (main coil) degaussing coil counteracts vertical components of the ship field, both induced and permanent. The intensity and polarity of the induced vertical field also change slowly according to the distance of the ship from the north or south magnetic pole. Current going through the coil is manually adjusted according to information in the ship’s degaussing folder. The M-coil power supply has a rating of 40 kW with a maximum output current of 182 amps at 220 volts DC.

c. FP-QP Coil - The FP-QP coil compensates for the longitudinal component of the permanent longitudinal magnetic field. Like the M-coil, control current is controlled manually. The coil power supply has a rating of 20 kW with a maximum output current of 91 amps at 220 volts DC. On board USS Boxer the FP-QP coil is disconnected.

d. FI-QI Coil - (2) two horizontal loops (1) one forward forecastle, (1) one aft quarterdeck, main deck. The FI-QI coil compensates for the longitudinal component of the induced field of the ship. The coil current is maximum at equator on an N-S / S-N heading, and minimum at the poles and on the E-W / W-E heading. The coil power supply has a rating of 26 kW with a maximum output current of 118 amps at 220 volts DC.

106.2 Describe the function and location of the following components: a. Degaussing Switchboard - Located at the forward IC Shop (5-47-0-C). It houses the following components: transformer, 24 volt DC power supply, ground detector and alarm panel assembly, computer assembly, and control power assembly. Provides control of manual coils, as well as the setting of the H-Zone and permanent bias.

b. Remote Control Panel - Located on bridge at 06-65-1-C, is an informal display. It can read the current in any of the degaussing coils and roughly adjust automatic (A and FI-QI) currents in emergency conditions when the automatic circuitry is not working.

106.3 State the purpose of deperming "Deperming" reduces induced permanent magnetization and brings all ships of the same class into a standard condition. This causes the inherent permanent magnetization, which remains after deperming, to be about the same for all those ships. Important for avoiding mines, satellites and submarines.


For questions or comments please contact:

kimberly.a.king@navy.mil

AZC(AW/NAC) Kimberly King

FC2(SW) Daniel A. Girimonte