Furuno LH-3000 Operator's Manual page 21

SAIL: Warning signal for sailboats, tug boats and tow boats underway. One 3-second
blast, followed by one 2-second interval, one 1-second blast, one 2-second
interval and one 1-second blast. Repeated every 120 seconds.
3 s
TOW: Warning signal for vessels under tow. One 3-second blast, followed by one
2-second interval, one 1-second blast, one 2-second interval, one 1-second blast,
one 2-second interval, and one 1-second blast. Repeated every 120 seconds.
3 s
STOP: Warning signal for power-driven vessel that is stationary. Two 3-second blasts,
with a 2-second interval between each blast, repeated every 120 seconds.
3 s
1 s
2 s
1 s
2 s
Sailing signal
2 s
1 s
1 s
2 s
2 s
Towing signal
2 s
3 s
120 s
Stop signal
120 s
1 s
120 s
2. OPERATION
15