3-15
3.9
Tow Vehicle Deployment
The SB-424 and SB-216S Tow Vehicles can be towed using the 35-Meter Kevlar Reinforced Tow Cable. A
steel cable can also be to increase the life of the tow cable. For towing in deep water, a single, armored
tow cable is required. The steel cable can be secured to the tow cable using electrical tape, making sure
there is enough built-in slack in the tow cable so that the entire load is supported by the steel cable.
CAUTION!
Do not tow the tow vehicle too close to the survey vessel. Towing in this
manner can cause the tow vehicle to be pulled in against the hull of the
ship due to the low pressure of the propeller wash and the effect of the
water flowing by the hull. In addition, sonar reflections from the hull
may be evident in the records.
The tow vehicle may be towed at speeds of up to 10 knots. However, to optimize performance and
minimize flow noise, it is recommended that the tow vehicle be towed at speeds of less than 5 knots. Lead
ballast in the nose of the tow vehicle provides towing stability by allowing the tow point to be placed as
far forward as possible and by making the tow point well above the center of gravity of the tow vehicle.
The tow point is factory adjusted so that the tow vehicle is level when it is towed in the water at 3 to 5
knots.
CAUTION!
Do not tow the tow vehicle with the nose angled up or down. Doing so
can degrade the sonar imagery. Before towing the tow vehicle, verify
that it is as level as possible when towing the tow vehicle at 3 to 5
knots.
3.9.1
Obtaining the Best Sonar Imagery When Towing
To generate good sonar imagery, the pitch of the vehicle, which is how much in degrees the nose is angled
up or down, must be less than one half of the -6 dB beam width of the acoustic pulse at its highest
frequency—and less at lower frequencies. As a rule of thumb, for a 0.5-meter long hydrophone array, the
-6 dB beam width at 10 kHz is 20 degrees. For
example, if you are transmitting a 2 to 15 kHz FM pulse using a tow vehicle with a 0.5-meter long receiving
array, such as in the SB-216S or SB-216D Tow Vehicle, you must keep the tow vehicle from pitching more
than about 7 degrees in either direction, or
Содержание Model 3100P Sub-bottom Sonar System
Страница 24: ......
Страница 29: ...2 5 Figure 2 4 Tiger Board Set SIBU aka Sonar Interface Board 0011637...
Страница 32: ...SECTION 2 SPECIFICATIONS 2 8 3100 P PORTABLE SUB BOTTOM 0004802_REV_F Figure 2 5 SB 216 Towfish Outline Drawing...
Страница 33: ...2 9 Figure 2 6 SB 424 Towfish Outline Drawing...
Страница 48: ...3 14 SECTION 3 SETUP AND ACTIVATION 3100 P PORTABLE SUB BOTTOM 0004802_REV_F Figure 3 11 Tap Test...
Страница 60: ...SECTION 5 TROUBLESHOOTING 5 4 Figure 5 1 35M Tow Cable Diagram 0002899...
Страница 61: ...5 5 Figure 5 2 3100 P Topside Interconnect 0004674...
Страница 62: ...SECTION 5 TROUBLESHOOTING 5 6 Figure 5 3 Wiring Diagram Spider Box SB 424 Tow Vehicle...
Страница 63: ...5 7 Figure 5 4 Wiring Diagram SB 424 Tow Vehicle...
Страница 64: ...SECTION 5 TROUBLESHOOTING 5 8 Figure 5 5 Wiring Diagram Spider Box SB 216S Tow Vehicle...
Страница 65: ...5 9 Figure 5 6 Wiring Diagram SB 216S Tow Vehicle...
