table | 
the navigating quartermasters on the bridge. Ap- 
proximate dead-reckoning positions are NOT accu- 
rate enough for the BT log sheets. Astronomical, 
loran, or radar fixes should be plotted and the exact 
positions of the times of BT lowerings derived by 
interpolation. 
BT No. Enter here the number stamped on the nose 
of the BT. 
Depth. Enter here the sounding in fathoms. 
Speed. The speed of the ship in knots. 
Surface temperature. Enter the surface temperature 
of the sea water, and indicate whether it was ob- 
tained from a bucket sample (B) or from the injec- 
tion thermometer in the engine room (I). 
Wind force. Use either the Beaufort scale or, if avail- 
able, an anemometer reading. If wind speed is used, 
be sure to enter the unit at the head of the column, 
i.e., knots, feet per second, etc. Also indicate the 
height of the anemometer above the waterline. 
Air temperature. Enter the dry bulb and wet bulb 
temperatures. 
Barometer. Enter the barometric pressure. 
Weather by symbols. Enter here the code number 
as found in Table I. 
Clouds. Enter the type and amount by code number 
from Tables II and Ill. 
Visibility. Enter the code number from Table IV. 
Sea. Enter the amount of sea by code number from 
Table V. 
Wire out. Record the amount of wire paid out in 
lowering the BT. 
Sample No. If a sample of sea water is taken at 
the same time as the BT observation, record the bottle 
number here. 
Observer’s initials. Initial the last column. If further 
remarks are required, make an asterisk (*) opposite 
the observer's initials, and record the remarks on the 
back of the sheet. 
Whenever any significant quantity of log sheets and 
BT slides has accumulated, mail them together to: 
Hydrographer 
U.S. Navy Hydrographic Office 
Washington 25, D.C. 
00 - 49 no precipitation at the ship at the 
time of observation 
00-19 
No precipitation, fog, duststorm, sandstorm or drifting snow 
at the ship at the time- of observation or during the pre- 
ceding hour, except for 09 
t 
00 Cloud development not observed or No bya oe 
not observable Piclnude 
01 Clouds generally dissolving or be- eee eee 
coming less developed Characteristic 
02 State of sky on the whole unchanged ‘change of the 
03 Clouds generally forming or devel- wae Fv duries 
oping 
04 Visibility reduced by smoke, e.g., 
veldt or forest fires, industrial smoke 
or volcanic ashes 
05 Dry haze 
06 Widespread dust in suspension in 
the air, not raised by wind at or 
near the ship at the time of ob- 
servation : 
07 Dust or sand raised by wind at or 
near the ship at the time of obser- 
vation, but no well developed dust 
devil(s), and no duststorm or sand- 
storm seen 
08 Well developed dust devil(s) seen at 
or near the ship within last hour, 
but no duststorm or sandstorm 
09 Duststorm or sandstorm within sight 
of the ship or at the ship during 
the last hour 
Haze, dust, sand, 
or smoke 
10 Light fog (visibility 1100 yds. or 
more) 
Shallow fog at the 
ship mot deeper 
than about 33 ft. 
11 Patches of 
12 More or less continuous 
13 Lightning visible, no thunder heard 
14 Precipitation within sight, but not 
reaching ground at the ship 
15 Precipitation within sight, reaching 
ground, but distant (i. e., estimated 
to be more than 3 miles from the 
ship) : 
16 Precipitation within sight, reaching 
ground, near to but not at the ship 
17 Thunder heard, but no precipitation 
at the ship 
18 Squall(s) 
19 Funnel cloud(s) (tornado or water- 
spout) 
20 - 29 5 
Precipitation, fog or thunderstorm at the ship during the pre- 
ceding hour but NOT at the time of observation 
ing the last hour 
20 Drizzle (not freezing) 
21 Rain (not freezing) ; 
22 Snow ae falling as 
23 Rain and snow Sibccmtta 
24 Freezing drizzle or freezing rain 
25 Shower(s) of rain 
26 Shower(s) of snow, or of rain and 
snow 
27 Shower(s) of hail or of hail and rain 
28 Fog 
29 Thunderstorm (with or without pre- 
cipitation) 
13 
Within sight dur- | 
