The Engineers Bell Book, NAVSHIPS 3120/1 (fig. 12-23), is a record of all bells, signals, and other orders received by the throttleman to change the speed and direction of the ships propellers. Entries are made in the Bell Book by the throttleman (or an assistant) as soon as an order is received. Entries are usually made by the assistant when the ship is entering or leaving port, or engaging in any maneuver that is likely to involve numerous or rapid speed changes. This procedure allows the throttleman to devote his undivided attention to answering the signals. The Bell Book is maintained in the following manner:

1. A separate bell sheet is used for each shaft each day, except where more than one shaft is controlled by the same throttle station. In that case, the same bell sheet is used to record the orders for all shafts controlled by the station. All sheets for the same date are filed together as a single record.

2. The time of receipt of the order is recorded in column 1.

3. The order received is recorded in column 2. Minor speed changes (generally received via the revolution indicator) are recorded in column 2 as the number of rpm ordered. Major speed changes (normally received via the engine order telegraph) are recorded by use of the following symbols:

1/3 - Ahead 1/3

2/3 - Ahead 2/3

I - Standard

II - Full

III - Flank

Z - stop

BEM - Back Emergency

BF1 - Back Full

B2/3 - Back 2/3

B1/3 - Back 1/3

4. The number of revolutions corresponding to the major speed change ordered is entered in column 3. When the order received is recorded as rpm in column 2 (minor speed changes), no entry is made in column 3.

5. The shaft revolution counter reading (total revolutions) at the time of the speed change is recorded in column 4. The shaft revolution counter reading-as taken hourly on the hour while the ship is underway-is also entered in column 4.

Ships and craft equipped with controllable pitch propellers must record in column 4 the propeller pitch in feet and fractions of feet set in response to a signaled speed change, rather than the shaft revolution counter readings. The entries for astern pitch are preceded by the letter B. Each hour on the hour, entries are made of counter readings. This helps in the calculation of engine miles steamed during those hours when the propeller pitch remains constant at the last value set in response to a signaled order.

On ships with gas turbine propulsion plants, a bell logger provides an automatic printout each hour. This printout is also provided whenever propeller rpm or pitch is changed by more than 5 percent, when the engine order telegraph is changed, or the controlling station is shifted. Provision must be made for manual logging of data in the event the bell logger is out of commission (OOC).

Before going off watch, the EOOW signs the Bell Book on the line following the last entry for that watch. The next officer of the watch continues the record immediately thereafter. In machinery spaces where an EOOW is not stationed, the watch supervisor signs the bell sheet.

NOTE: A common practice is also to have the throttleman sign the Bell Book before it is signed by the EOOW or the EOOWs relief. The Bell Book is maintained by bridge personnel in ships and craft equipped with controllable pitch propellers and those in which the engines are directly controlled from the bridge.

When control is shifted to the engineroom, how-ever, the Bell Book is maintained by the engine-room personnel. The last entry made in the Bell Book on the bridge shows the time that control was shifted. The first entry made in the Bell Book in the engineroom shows the time that control was taken by the engineroom. Similarly, the last entry made by engineroom personnel shows the time that control was shifted to the bridge. When the Bell Book is maintained by bridge personnel, it is signed by the officer of the deck (OOD) in the same manner as prescribed for the EOOW. Alterations or erasures are not permitted in the Bell Book. A single line should be drawn through the incorrect entry and the correct entry should be recorded on the following line. Deleted entries are initialed by the EOOW, the OOD, or the watch supervisor, as appropriate.

Figure 12-23.-Engineers Bell Book.

SUMMARY

In this chapter, we have discussed the various devices that transmit the power developed by the engine to the propeller of a vessel. In general, these devices consist of clutches, re-verse gears, reduction gears, and the related shafting and bearings. A transmission requires an activating force to engage or disengage the clutch. This force may be in the form of mechanical, hydraulic, pneumatic, or elec-tromagnetic energy. Some vessels are provided with controllable pitch propellers. With this arrangement, no reversing gear is required because the direction of propeller thrust can be changed without changing the direction of shaft rotation.

Learning to recognize various symptoms will help you to identify the abnormal conditions that may occur in clutches, couplings, and various associated gears. You should become familiar with the causes of gear, clutch, and coupling problems. By recognizing the causes of these problems, you can learn to prevent their reoccur-rence through the application of correct operating procedures and proper upkeep and maintenance.

If you are uncertain as to any of the information in this chapter, we recommend you reread the sections in question before continuing to chapter 13.