MVP Operators’ Guide 3
OM-09000-Z-04-004D AML Oceanographic Ltd.
Figure 2: Attaching the Tow Cable Messenger
2 OPERATING INSTRUCTIONS
CAUTION: It is highly recommended to not use Freewheel Mode when performing
stationary profiles (when the vessel is not underway). Conducting
Freewheel operations will deliver a shock load to the tow cable on the
system when the brake is applied, especially in shallow water deployments.
When performing underway Freewheel deployments, the tow cable creates a
virtual underwater sheave which prevents a shock load on the tow cable
from occurring. When performing computer automated Stationary Profiles,
the profiling mode in the MVP Controller software should be set to Constant
Speed or Constant RPM.
2.1 OVERVIEW
Once the ‘messengers’ are installed, specific to the intended vessel survey speed, profiling
operations can begin by turning the system on in HAND mode, manually winching the fish out of
its deck cradle, rotating the boom overboard (securing with a side stay if operating off the side of
the ship) and lowering the fish into the water to its pre-determined towed position.
NOTE: At the towed position, the Dock messenger should be positioned between the
Inner and Outer Sheave limit switches (the Dock messenger is to be installed
according to Section 1.3).
The winch is then switched to AUTO mode and computer automated profiles can now be
conducted from the lab. Each profile conducted will start and finish with the fish at the towed
position. When profiling operations are complete, the winch is switched back to HAND mode,
the fish is manually winched out of the water, the boom is rotated inboard and the fish lowered
into its deck cradle. The system is then switched to OFF from HAND mode and shut down.
If the system has been idle for a couple of days or longer, the Main Power Lever at the High
Power Electrical Box should be turned on 12 hours prior to operating the winch. This will allow
the anti-condensation heaters in the electric motor to remove any condensation.
WARNING: The MVP system should only be operated by trained personnel. Keep all
personnel away from the winch during profiling operations.
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