348 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
valve. It acts quickly, is not liable to derangemeut, and is easily adjusted by pinning 
the connecting rod h through a hole in the lever, which gives the valve the desired lift. 
A leading hlocl; h, 13 feet forward of the drum, may be considered a part of the 
governor, although detached from it. A spiral spring in its stem gives it a horizontal 
motion of about G inches, for the purpose of taking up a portion of the slack rope 
Avhen it surges on the hoisting drum, thus reducing the jar and aiding in the main- 
tenance of a unifoi’m tension. 
To adjust the governor, uiiAvind a fathom or two of dredge rope from the reel and 
attach a scale to the bight, between the reel and leading block n ; close the pressure 
valve and open the throttle wide; then by adjusting the nut e, screwbolt g, and con- 
necting rod li admit steam to the reeling engine until the desired tension say, 300 
pounds, is shown on the scale. It is advisable to verify it occasionally until the 
attendant becomes familiar with his duties, when he will readily make the necessary 
adjustment while the engines are in operation, by first shutting oft steam through 
the pressure valve until the dredge rope is seen to slip on the hoisting drum, then 
gradually admitting it again until the rope is properly Avound on the reel Avithout 
unnecessary tension. 
The J'riction clutch on the drum of the reeling engine is adjusted by a lever, so 
that the reel slips and ceases to turn when the prescribed limit of tension is exceeded, 
as happens if the pressure valve fails to act, or if the hoisting engine is suddenly 
reversed, in an emergency, for the immediate veering of roiie. 
The action of the governor is as follows: When tension is applied to the dredge 
rope, the pressure on the sheave a forces the frame h fonvard until it is arrested 
l>y the increasing compression of the spiral spring/; the forward movement actuating 
the bell crank d and connecting rod h causes the pressure A^alve to close and shut off 
steam in proportion to the moAmment, finally stopping the engine Avhen the limit has 
been reached. The reverse movement, resulting from diminished tension on the rope, 
gradually admits steam through the pressure valve and starts the engine. 
LEAD OF THE DREDGE ROPE. 
The rope liaAdng been wound on the drum I of the reeling engine (plate xxix) is 
first led through the automatic guide m, then under and over the leading block u, under 
and over the governor sheave a, thence to the hoisting drum o of tlie dredging engine, 
around Avhich five turns are taken from foi Avard aft and from starboard to port. The 
end is then carried aloft and rove, from forward aft, through the bhAck at the loAver 
end of the accumulator q, which is suspended from the mast, then under the register 
sheave f in the heel of the dredging boom, and finally over and under the dredging 
block w at the boom end. 
The dredging hoom s is of spi'uce, 3G feet in length and 10 inches in diameter. 
Its outer end is inclosed in a heavy brass cap and band, Avhich has four eyebolts 
at equal intervals on its periphery, one each for the topping lift r and dredging 
block u; also one each on the forward and after sides for the boom guys. A capped 
sleeve of brass incases its heel. It is about 2 feet in length, mortised to receive the 
register pulley t, and enlarged on its sides to form bearings for its shaft. The heel of 
the boom is supported by a hinged socket bolt which passes through a hole in a heavy 
composition band on the foremast, u])on AA’hich it pivots and turns freely and is pre- 
vented from unshipping by a nut and Avasher. 
