Sea bed drilling with light equipment

A description of method and equipment for subsoil exploration under relatively-deep water is given. The drilling is carried out from a small drilling platform, a self-propelled catamaran with deck dimensions 5 metres width/8 metres length. The drilling rig is a 1,7 tons caterpillar tractor with operating capasities of 4 tons downward thrust and 150 kgm torque at 0-100 rpm, supplemented with water flushing equipment and a rock drilling percussion hammer for penetration of stony soils and bedrock. The drilling method is the socalled “total sounding” recently develloped in Norway, modified to meet special conditions in sub-sea operation. Drilling with the equipment has been carried out under 60 metres of water. It is considered possible to increase the water depth to 80 metres after making minor modifications in the equipment. A limiting condition is that the operation is restricted to sheltered waters with wave height less than about 0,5 metres. Economically, the method is much cheaper than a drilling ship which is normally called for for this range of water-depth.