MANUAL OF TIDE OBSERVATIONS 45 



the lead in the pencil may have a sensible effect on the hour-marking 

 device. A second adjustment consists of changing the angle which 

 the recording pencil makes with the paper by means of an adjusting 

 screw (40, fig. 7) . A third adjustment changes the angle between the 

 striker weight (29, fig. 8) and the upright supporting the tripping 

 rod. In general this angle will not differ greatly from 90°. The 

 weight is held in position by a binding screw (30, fig. 8), but because 

 of the strain produced by the hourly dropping of the weight there 

 may be a slipping at times. The fourth adjustment relates to the 

 position of the striker lifter (33, fig. 9) attached to a spindle from the 

 time clock. This is secured to the spindle by a binding screw (32, 

 fig. 9) and during the first half of each hour its position should 

 be vertical. During the last half of each hour its position changes 

 through the action of a cam in the clock. 



129. Cleaning pencil screw. — One of the most common sources of 

 trouble, which cannot be overemphasized, in the operation of the 

 automatic gage, is the sticking of the pencil arm on the pencil 

 screw. Even when the pencil screw itself appears clean, there may 

 be an accumulation of dirt in the bearing of the pencil arm. Also, 

 while the arm may operate freely in covering the normal range of 

 tide, there may be a sticking as it advances toward either end of 

 the screw for an unusually high or low water. The following oper- 

 ating difficulties frequently have their origin in a sticking pencil 

 screw: (a) recording pencil thrown back off the paper on a falling 

 tide, (h) curve recorded on falling tide less legible than that of rising 

 tide, (c) paper torn by pencil digging in on a rising tide, (d) dis- 

 tortion in tide curve, especially a flattening at time of high or low 

 water and steps on a rising or falling tide, (e) float wire broken 

 or off drum. 



130. The pencil screw should be cleaned at least once each month 

 and at other times when there is any evidence of sticking. The 

 latest type gage is provided with a removable pencil screw which 

 can be taken out of the gage without disturbing any of the wiring. 

 It is released by backing off the capstan bearing pin (45, fig. 9) 

 at the forward end of the screw. The other end of the screw is 

 connected with the drum shaft by a slotted joint. When replacing 

 the pencil screw in the gage, the pencil arm should be placed in the 

 same position as before with allowances for any change in the height 

 of the tide in the meantime. While out of the gage, the pencil 

 screw and the inside of bearing of the pencil arm are to be thoroughly 

 cleaned with kerosene or nonleaded gasoline and any roughness due 

 to corrosion removed by a fine file. The use of emery or crocus 

 cloth is to be avoided. Before replacing the pencil screw in the 

 gage, the movement of the pencil arm along the entire length of the 

 screw as well as the functioning of the return springs at the ends 

 should be checked in the manner described in paragraph 87. Lubri- 

 cating oil must not be used on the pencil screw or in the bearing of 

 the pencil arm, as the oil tends to collect dust from the atmosphere 

 and when dry forms a sticky film on the metal surfaces. The move- 

 ment of these parts during the operation of the gage is so slow that 

 the friction between the clean dry metal surfaces is practically 

 negligible. 



735445 O - 47 - 4 



