Chapter 11 Auxiliary Electrical Equipment

CHAPTER 11

AUXILIARY ELECTRICAL EQUIPMENT

LEARNING OBJECTIVES

Upon completion of this chapter you will be able to do the following:

Describe the operating and testing procedures of the ship's whistle.

Explain the requirements for performing maintenance on the ship's whistle.

Describe the components, operating procedures, and maintenance procedures

of the microfiche reader-printer

Describe the components, operating procedures, and maintenance procedures

of the cathodic protection system.

Describe the inspection, troubleshooting, and corrective maintenance proce-

dures of auxiliary equipment.

INTRODUCTION

sound pressure level of the ship's own signal at

listening posts shall not exceed 110 dB(A), and so far

IC Electricians are required to maintain various

as practicable should not exceed 100 dB(A).

types of auxiliary equipment aboard ship. This chapter

will describe the components, operating procedures,

FREQUENCIES AND RANGE

and troubleshooting and maintenance procedures of

some of the auxiliary equipment that you will be

The fundamental frequency of the whistle signal

involved with. This chapter will also introduce you to

lies between the 70- to 700-Hz range. The audibility

cathodic protection systems installed on naval ships.

range of the whistle signal is determined by those

frequencies (which may include the fundamental

SHIP'S WHISTLE

and/or one or more higher frequencies) that lie within

the 180 to 700 ( + 1 percent) range and that provide

As an IC Electrician, you will be required to do

sound pressure levels specified in the following

preventive maintenance and repairs on the ship's

paragraph on intensity. The range of audibilty is for

whistle. This is a relatively simple system, but it is of

the utmost importance. The ship's whistle is used to

information, and is the approximate range at which a

signal other vessels of the manuevers your ship may

whistle may be heard on its forward axis (90 percent

be doing. It is also used, in conditions such as heavy

probability) in conditions of still air on board a ship

fog, to warn other ships of the location of your ship.

having the average background noise level at the

listening posts. This shall be assumed to be 68 dB in

LOCATION OF WHISTLE

the octave band centered on 250 Hz and 63 dB in the

octave band centered on 500 Hz. Values given can be

When a directional whistle is to be used as the only

regarded as typical, but under conditions of strong

whistle on a ship, it is installed with its maximum

wind or high ambient noise level at the listening post,

intensity directed straight ahead. A whistle should be

range may be reduced. In practice, the range at which

placed on a ship as high as practicable to reduce

a whistle may be heard is variable and depends on

interception of the emitted sound by obstructions and

to minimize risk of hearing damage to personnel. The

weather conditions.

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