DEEP-SEA EXPLORATION. 
391 
her stern to the wind when backing’, and this tendency becomes a fixed habit whenever 
a trawl is dragging. On the other hand, tlie vessel is always under control when 
steaming ahead, and may work with the wind from a point on the bow to right astern, 
providing wind and current are in the same direction. 
Starting ahead slowly, the trawl is swung out, lowered to the surface of the water, 
and towed until the frame assumes a liorizontal position, and the trawl net, the pocket, 
the mud bag, and wing nets all trend aft and are seen to be clear. 
When the vessel reaches her course under a speed of 3 to 3 knots, with the lee 
engine only working, the order is given to lower away. The first few fathoms should 
be veered with promptness and sufficient rapidity to insure sinking the trawl well 
below the propeller, after which the commanding officer will prescribe the rate at 
which it shall be veered and regulate the speed of the vessel. Under ordinary con- 
ditions it would be about 3 knots per hour, and the first 200 fathoms of dredge rope 
would be veered at the rate of about 30 fathoms per minute. 
The engineer at the dredging engine calls out each 100 fathoms, the recorder 
notes the time and stands, watch in hand, ready to increase or check the rate of 
veering, which is never allowed to exceed the i^rescribed limit. 
By the constant use of the dredging quadrant the commander knows the angle 
of the rope at all times during its descent and so regulates the speed of the vessel 
and rate of paying out that the sinking of the trawl is facilitated, at the same time 
guarding against its capsizing or the rope kinking, contingencies that inevitably 
follow too rapid veering of the latter or too low speed of vessel. 
Dredging Table No. 1. 
Depth of 
T^'atcr. 
Speed of 
ship 
while 
lowering 
trawl. 
Length of 
dredge rope 
re(iuired 
for a given 
depth of 
water. 
Time re- 
quired to 
veer each 
100 fathoms 
of dredge 
rojie. 
Angle of 
dredge rope 
while 
lowering 
trawl. 
Angle of 
dredge rope 
while 
dragging 
trawl. 
Allowance 
of dredge 
rope fur 
catenary 
curve. 
Fathoms. 
Knots. 
Fathoms. 
Minutes. 
Degrees. 
Degrees. 
Fathoms. 
100 
3 
200 
34 
CO 
55 
25 
200 
3 
400 
3i 
60 
55 
44 
400 
.3 
700 
34 
60 
52 
50 
600 
I, 000 
4 
55 
50 
60 
800 
2i 
1,200 
4 
50 
44 
90 
1, 000 
2i 
1, 500 
4 
50 
40 
no 
1,500 
2i 
2,166 
4 
50 
40 
206 
2, 000 
2 
2, 070 
4 
45 
35 
250 
3, 000 
2 
4,000 
4 
40 
35 
350 
Absolute rules can not be laid down for lowering the beam trawl, as its rate of 
descent varies with the conditions, which are rarely the same during two successive 
casts and frequently change more than once in the same haul. Yet dredging table 
No. 1 shows apiiroximately the method followed on board the Albatross, which, in the 
light of experience, is considered safe practice under normal conditions. 
The angles in this table are from the vertical. The speed at which the trawl is 
dragged along the bottom is not given in the table. Tt is usually less than that in the 
column for lowering, but is so variable that the safest plan is to maintain the angle 
as nearly as possible by the use of the dredging quadrant, regulating the speed as 
required, regardless of the actual progress of the vessel through the water. 
The scope of dredge rope is given for ordinary practice, yet for rapid dragging 
in comparatively shoal water three and even four times the depth is allowed. 
The rate of 3.^- minutes per 100 fathoms for veering the dredge rope has been 
maintained nx) to 2,000 fathoms or more, sometimes successfully, but it is running on 
