The i-Plough is a pre-lay plough spread with the capability to perform boulder clearance, pre-cut trenching and backfill services once the product has been laid. The i-Plough can operate in each mode independently or carry out the boulder clearance and pre-cut trenching simultaneously in a single pass should ground conditions permit. By carrying out the boulder clearance and pre-cut activities simultaneously, it allows for two spoil berms to be created. The surface and surface boulders are unearthed and relocated to the outer spoil berms of cleared boulders, away from the pre-cut trench (not used for backfilling). The siphoned soil to be relocated to the inner spoil berms will later be used to backfill after the product has been installed.
Boulder Clearance & Pre-Cut Trenching
The key to pre-lay ploughing is ensuring that any surface or subsurface boulders in the ploughing path are removed before cutting the trench. This ensures that back-filling spoil is free from boulders, as they can damage the cable product when backfilled into the trench and ensure no boulders interfere with the ploughing process.
Pre-cut trenching works provide confidence the required trench depth is achieved without handling the product, ensuring minimal risk of product damage in challenging soil conditions.
The Backfill operation is expected to happen sometime after the product is installed. Before backfilling, some movement of the trench spoil can be expected (dependent on the soil type and subsea flow environment). As a result, the i-Plough is designed to move the spoil further away from the trench
wall than a standard plough to reduce the amount of natural material in-fill over the time between trenching and back-fill operations. Noting that in the case of trench collapse, the product can be jetted to the required burial depth without obstructions. Additionally, if circumstances are preferred, the (end) client can cover the product by back-filling the spoil removed from the V-trench during the ploughing process.