Review of Cabling Techniques and Environmental Effects Applicable
Review of Cabling Techniques and Environmental Effects Applicable
Review of Cabling Techniques and Environmental Effects Applicable
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Cable types <strong>and</strong> installation techniques<br />
Another type <strong>of</strong> Advanced Cable Plough is the modular cable plough, the concept<br />
for which was originally conceived in the 1980s. The principle <strong>of</strong> the modular<br />
plough is to have a plough system with an interchangeable plough share which<br />
allows the operator to either fit a narrow share for cable burial or to fit a modular<br />
V-type share for the burial <strong>of</strong> flowlines or small flexible pipelines.<br />
This type <strong>of</strong> plough has not proved popular <strong>and</strong> most operators have opted to<br />
design <strong>and</strong> build a plough system specifically tailored to the market they wish<br />
their plough system to operate in. An example <strong>of</strong> a modular plough is detailed<br />
in Table 3.8 below. It is believed that this plough system has only been used in<br />
cable burial mode; however, this has not been confirmed.<br />
Table 3.8: Modular Cable Ploughs<br />
PLOUGH MODULAR CABLE PLOUGHS<br />
Type Maximum Burial Depth Operator Manufacturer<br />
Modular plough system<br />
(cables or pipes)<br />
Rock ripping ploughs<br />
1.2m CTC Marine Projects SMD Hydrovision<br />
Ltd<br />
The Rock Ripping Ploughs were developed in response to requirements from<br />
the subsea telecommunications market to provide a capability to protect<br />
cables in areas where telecom cables passed over seabeds which consisted <strong>of</strong><br />
outcropping rock, or where the seabed strata was exceptionally hard <strong>and</strong> outwith<br />
the capabilities <strong>of</strong> a conventional narrow share plough. This requirement was<br />
primarily driven by fishermen trawling in seabed areas where such seabed<br />
conditions exist. Historically the fishermen would have avoided such areas<br />
owing to the risk <strong>of</strong> snagging gear. However, the need to find new fishing<br />
grounds has now forced the fishermen to work in these more difficult areas <strong>and</strong><br />
in deeper waters.<br />
Historically when a cable had to be buried in rock the traditional approach would<br />
have been to use a rock wheel cutter. These tools can cut an efficient trench,<br />
but tend to make relatively slow progress depending on the nature <strong>of</strong> the rock.<br />
Furthermore, the wear rate on the cutting teeth can be substantial. Therefore, the<br />
rock ripping plough was developed to meet this new challenge.<br />
A Rock Ripping Plough has an additional, folding, rock penetrating tooth which<br />
is fitted to the leading edge <strong>of</strong> the plough share. The rock penetrating tooth<br />
significantly increases the ability <strong>of</strong> the rock ripping plough to penetrate <strong>and</strong> cut<br />
trenches in very hard ground seabed conditions. The overall performance <strong>of</strong> the<br />
plough is not generally affected in any way when the plough is cutting the trench<br />
in rock ripping mode.<br />
Table 3.9 lists a number <strong>of</strong> rock ripping ploughs which are currently available in<br />
the marketplace. Figure 3.17 shows a rock ripping plough; the rock penetrating<br />
tooth is clearly visible on the leading edge <strong>of</strong> the plough.<br />
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