Investigation into the effect of forecutters on plough performance

Pipeline ploughing is a common method used to bury offshore pipelines for protection. During ploughing, rate effects which occur in fine grained granular soils increase the tow force required by the support vessel and may reduce achievable plough velocities, thereby increasing the duration of a contract. The share of the plough ‘cuts’ the trench with some ploughs featuring a second, smaller cutting tool known as a forecutter which sits in front of the share. The effectiveness of the forecutter in reducing tow forces during ploughing has been investigated by reduced-scale model testing and is outlined herein. The forecutter is shown to be beneficial
in reducing the rate effect but has a negative impact on the ‘static’ component of tow force. Conditions where the forecutter should be of overall benefit to reducing the tow force during ploughing are described.