| Tweet |
Custom Search
|
|
|
||
 TB 55-1900-201-45/1
that the quill shaft grease seals have not failed. In cases where the seals have failed, the internal conical brake shoes
shall be replaced.
2-85. Falls, Blocks and Sheaves. When the appurtenances are inspected, lifeboats falls, blocks, sheaves, etc., shall
be examined for condition and operation. One critical area on gravity davit lifeboat falls is that between the bite end and
the floating block. In this area, special attention shall be given to the section which passes over the standing blocks on
the davit heads. Rust has a tendency to accumulate in this area due to the fact that the falls in this area do not move
and are not self-lubricated. In addition, parts of the wire falls which are hidden behind blind sheaves may sometimes be
neglected because they are not easily reached for lubrication. Also, in some instances, the wire falls, where they enter
the floating blocks may chafe on the upper pin of the blocks where the blocks are in the housed position.
Lifeboat falls shall be renewed if:
(a) a number of wire threads are broken.
(b) a section appears attenuated or deformed.
(c) improper size, type or length.
(d) fishhooked.
The surveyor shall observe that all sheaves are in good condition and free to move, and that area on the davit arm be-
hind the sheaves is free from corrosion and not holed. He shall also examine the condition of turnbuckles, sockets,
shackles, etc., where applicable.
2-86. Limit Switches. All limit switches, controllers and emergency disconnect switches shall be opened for examina-
tion and testing. The limit switch shall be examined for correct cutout position, when the lifeboat is hoisted. Also, the
condition of contacts and roller alignment shall be noted. Arms on limit switches shall be inspected to insure that they
are not frozen and that they are properly keyed to the shaft. Plugs should be removed from motors to drain and conden-
sation accumulation. As the boat is raised, each limit switch shall be tested by hand operation of the limit switch arm and
also automatically allowing the davit arm to actuate the switch. In both cases, the switch should operate properly. The
main line disconnect is tested by opening while raising the lifeboat.
2-87. Davit and Winch Repair. Due to the strength considerations involved, the repair or replacement of parts for
davits and winches will be as original construction. All materials used and procedures followed shall be in accordance
with the vessel drawings.
2-88. Lowering Controls. During the lowering of the boat, checks shall be made that the governor brake adequately
controls the speed of lowering and the winch brake is capable of stopping and holding the lifeboat by the action of the
counterweight alone.
2-41
|
||
|
||
