COMPLIANT LINEAR TRACTION DRIVE (CLTD)
Provision has been made to load/unload cable from the
CLTD without the need to separate the cable or to thread it through. The side of the CLTD
opposite the drive chain has four aluminum blocks which can be removed to allow the
streamer to pass through. The blocks perform a double duty function, in that they act as
cable guides inside the CLTD, as well as setting the gap between the belts. The belt gap
is sized based on spacers and "bird collars" that are typically used with a
seismic streamer, although much larger components can be accommodated.
Safety covers are provided for the top side of the CLTD
and for the drive chain.
MANUFACTURE AND TEST
The CLTD is built and tested at Spectrum's facility in Peterborough, Ontario.
Each unit undergoes a complete Acceptance Test Procedure (with subsequent report
generated). The ATP includes the following tasks as a minimum.
- Visual & mechanical inspection and checks
- Pneumatic system checks
- Hydraulic system checks
- Operational tests with sample streamers
- Weight check
APPLICATIONS
The CLTD has been in operational service since early 1996. The CLTD can be used
for both dockside-to-ship cable loading, and as a shipboard detensioning device. The
CLTD's ability to take up the load of an overboarded cable or array significantly reduces
loads on winches. This allows a winch to function in a more appropriate cable storage
role, without having to handle high towing, payout and retrieval loads.
NAVAL & SEISMIC SURVEY
Applications include dockside-to-ship array streamer loading, and ship or submarine cable
deployment and detensioning.
OTHER POSSIBLE APPLICATIONS
- Ocean bottom cable laying
- Other high strain cable handling applications.
REQUIREMENTS & OPTIONS
Base Support Requirements
The CLTD is mounted using one lug on each of the four feet. They are sized for 3/80 bolts
using the mounting pattern shown in Figures 1 and 2.
The mounting structure must be capable of withstanding the weight of the CLTD and a
potential cable tension load of up to 1000 lb. Depending on the application, the CLTD can
have horizontal alignment pulleys, as well as four retractable wheels for easy
maneuverability.
Weight estimates for the components are listed below:
CLTD basic unit 341 kg (750 lbs.)
Horizontal alignment pulleys 91 kg (200 lbs.)
with support brackets (pair)
and retractable wheels
TOTAL 432 kg (950 lbs.)
Total weight when crated
approx. 636 kg (1400 lbs.)
Streamer Guidance Requirements
Horizontal alignment pulleys provide proper guidance and centerline alignment for
the streamer into the CLTD. They include two support frames and pulley units which bolt
directly to the existing CLTD frame.
Maximum Allowable Size of Connectors, "Bird
Collars," and Other Attachments
The maximum size of component that the current design of CLTD can handle is the "bird
collars" on a streamer system complete with Velcro protective boots. The approx.
diameter is 4.5 in., and represents the upper limit of an object that could pass through
the unit. This limitation arises from the sizing of the "throat" at the entrance
to the CLTD, in the horizontal plane.
