Subsea Tracked Cable Trencher – OTTER

OTTER subsea trencher an efficient and reliable tool for burial of wide range of cable types of different sizes at water depths up to 50 m. The trencher is built on a tracked base with versatile configuration applicable for mechanical chain cutter installation (for firm clay and rock) as well as jetting tool (for sands and soft clays).

Highlights

Water depth up to 50 m, trench depth up to 2,2 m;
Max. product size – 120 mm, min. bend radius –1,5 m;
Capability to use mechanical, jetting and combined trenching method;
High performance in a wide range of soils (from sands to rock);
Remote control from host vessel with no requirement of divers constant use;
Optimal balance of weight and power that provides for stable traction with the sea bottom;
Fully hydraulic drive system;
Provision for acoustic positioning;
Capability of simultaneous trenching and backfilling of the trench by ejecting with water jet supplied from surface pump;

Equipment set:

Subsea trencher (dimensions: 9 m х 4,2 m х 2,6 m; weight: 8 t) – 1 no.;
Control cabin based on 10 ft container (dimensions: 6 m х 2,4 m х 2,6 m; weight: 5 t) – 1 no.;
Hydraulic power unit (dimensions: 3,5 m х 2,1 m х 2,3 m; weight: 5 t) – 1 no.;
Water pump (dimensions: 3,9 m х 1,9 m х 2,7 m; weight: 5,5 t) – 2 nos. (during jetting).

General:

Depth rating: 0-50 m;
Dimensions: 9 m х 4,2 m х 2,6 m;
Weight in air: 8 t;
Drive: self-propulsive unit;
Speed (no burial): 0 – 1 km/h;
Speed (burial): 0,01 – 0,5 km/h;

Mechanical:

Frame structure: carbon steel;
Base mounting: track, excavator-type;
Tracks: nylon, 1,1 m wide.

Mechanical trenching system (chain cutter):

Configuration: AFT MH100;
Trench depth: 0 – 2,2 m;
Trench width: 250 mm.
Soil type: sandstones, clays (up to 500 kPa), soft rock
Max. product size: 120 mm
Min. bend radius: 1,5 m
Water flow: 1360 m3 /h (up to 16 bar)
Jet nozzles: 20 holes for different size nozzles

Control system:

Remote functions: track drive, depressor deployment, chain drive, cameras and lighting activation, USBL beacon activation, extra control channels for optional equipment
Monitoring and data acquisition: PC Advantech TPC-1751T-E3AE

Surveillance system:

Cameras: C-technics CT3015, 2 nos.
Lighting: C-technics CT4006 Mini LED, 2 nos.
Acoustic positioning: C-technics CT4006 Mini LED, 2 nos. Acoustic positioning Mini-Ranger 2 System Kit (option)

Sensors:

Trench depth: Rota LT LJA0500M
Pitch & Roll: G-NSDOG2-002
Cable angle at bellmouth: RT 0579B; RTS 090 1TS 0579
Tracks speed: RNF-664302-4SP160 RN3/20/8
Chain cutter speed: RNF-664305-4SP160 RN3/40/32
Heading: KVH C-100 fluxgate compass