Construction of lifeboat winches.
Lifeboat winches shall be of such strength that the lifeboat may be lowered safely with its full complement of persons and equipment. Additionally, a lifeboat winch used in hoisting an emergency lifeboat of a passenger vessel shall be capable of meeting the test specified in § 160.015-5(b)(9). A minimum factor of safety of six on the ultimate strength of the material shall be maintained at all times based on the approved working load.
Worm gears, spur gears, or a combination of both, may be used in the construction of lifeboat winches. All gears shall be machine cut and made of steel, bronze, or other suitable material properly keyed to shafts. The use of cast iron is not permitted for these parts.
Screws, nuts, bolts, pins, keys, etc., securing moving parts shall be fitted with suitable lock washers, cotter pins, or locks to prevent them from coming adrift.
Drums shall be so arranged as to keep the falls separate, and to pay out the falls at the same rate. Clutches between the drums shall not be permitted unless bolted locking devices are used.
The diameter of the drums shall be at least 16 times the diameter of the falls.
A weighted lever hand brake shall be used to control the lowering by the lifeboat winch. It shall be of a type which is normally in the “on” position unless manually held in the “off” position, and shall return to the “on” position as soon as the brake lever is released.
In addition to the hand brake, a governor type brake shall be fitted so as to control the speed of lowering of the lifeboat in accordance with § 160.015-5(b) (4) and (5).
Positive means of lubrication shall be provided for all bearings. When worm gears are used the worm wheel shall operate in an oil bath. Means shall be provided so that the oil level in the gear case may be easily checked. The manufacturer shall furnish a lubrication chart for each winch together with a plate attached to the winch indicating the lubricant recommended for extremes in temperature.
When lifeboat winches are fitted with power for hoisting, a suitable clutch shall be fitted to disengage the power installation during the lowering operation. In addition, the air or electric power outlet for a portable power unit shall be located adjacent to the winch where the unit is to be coupled. This power outlet shall be interconnected with and protected by the same system of safety devices as required for winches with built-in-motors.
Where power-driven lifeboat winches are used, including those driven by portable power units, such as air or electric drills, positive means shall be provided for controlling the power to the lifeboat winch. This shall be so arranged that the operator must hold the master switch or controller in the “on” or “hoist” position for hoisting, and when released will immediately shut off the power.
Limit switch and emergency disconnect switch requirements:
A main line emergency disconnect switch shall be provided, the opening of which will disconnect all electrical potential to the lifeboat winch. This switch shall be located in a position accessible to the person in charge of the boat stowage, and for gravity davit installations, shall be in a position from which the movement of both davit arms can be observed as they approach the final stowed position.
Where power driven winches are used with gravity davits, two limit switches, one for each davit arm, shall be provided to limit the travel of the davit arms as they approach the final stowed position. These switches shall be connected in series, they may be connected in either the control or the power circuit, and they shall be so arranged that the opening of either switch will disconnect all electrical potential of the circuit in which the switches are connected. These switches shall be arranged to stop the travel of the davit arms not less than 12 inches from their final stowed position and they shall remain open until the davit arms move outboard beyond the tripping position of the switches.
Other arrangements equivalent in design and safety will be given special consideration.
Where power driven winches are used, satisfactory means shall be provided to disconnect power to the winch before a hand crank can be engaged with the winch operating shaft, and this interruption of power shall be maintained while the hand crank is so engaged. Mechanical means for accomplishing the above, such as throw-out couplings on the sockets of the hand cranks, will be given special consideration.
Motors, switches, controls, cables, etc., shall be of the waterproof type if installed on an open deck. Controls may be of the dripproof type if installed in a deck house or under deck. Installations shall be in accordance with subchapter J (Electrical Engineering) of this chapter (Electrical Engineering Regulations, CG-259).
All moving parts shall have suitable guards.
Welding, when employed, shall be performed by welders certified by the U. S. Coast Guard, American Bureau of Shipping, or U.S. Navy Department, and the electrodes used shall be of an approved type.
Inspection openings shall be provided in the winch housing or the housing itself shall be so arranged as to permit examination of the internal working parts.
Motor clutches, when used, shall be of either frictional or positive engaging type. When one motor is used for two winches, the clutch shall be so arranged that only one winch shall be engaged at any one time. The clutch operating lever shall be capable of remaining in any position when subject to vibration and shall be so arranged that when in neutral position, both lifeboats may be lowered simultaneously.
[CGFR 49-18, 14 FR 5111, Aug. 17, 1949, as amended by CGFR 51-20, 16 FR 5443, June 8, 1951; CGFR 58-31, 23 FR 6883, Sept. 6, 1958; CGFR 65-9, 30 FR 11465, Sept. 8, 1965; CGD 72-133R, 37 FR 17039, Aug. 24, 1972; CGD 73-103R, 39 FR 11273, Mar. 27, 1974]