Several pre-piles of the Wikinger jacket foundations need to be drilled before further pile driving can continue. To perform these secure drilling works, Boskalis requested Barge Master to deploy their T700 motion compensation platform.
The drill rig is located at the outer end of an outrigger frame. This cantilever construction is designed to transfer all transit and operational loads via the BM-T700 platform to the deck of the Stemat 92 barge.
The Sennebogen 7700 crane will bring the Bottom Hole Assembly (BHA) in position at the drill rig. The BHA is slowly lowered into the direction of the obstructed pre-pile. A stabbing cone, on top of this pile, guides the BHA into the pile and prevents damage on the drill bit. The design of the cone enables the crane to retrieve the cone easily after use. To ensure the crane and its counterweight remains in place during transit and operation, seafastening constructions were attached to the motion compensated platform. The crane is vertically supported on crane mats and horizontally via stoppers. During transit condition, the 20t weighing crane boom is resting on the boom rest, which is supported by three stacked containers.
#Barge Master, T700, Wikinger jacket foundations, Boskalis
TWD designed seafastening structures for the Barge Master platform, crane, boom rest, outrigger frame, secondary containers and we re-designed the Bottom Hole Assembly (BHA) seafastening construction to enable easy repair and maintenance. To guide the BHA to the seafastening grillage, we designed three additional bumpers for the BHA seafastening structure, which were seafastened via wing plates and stoppers.
Furthermore, we designed a stabbing cone, bollards and performed drill string checks and deck layout calculations. Simple seafastening structures, such as HEM beams, base plates, kicker plates, horizontal stoppers and uplift brackets were designed for the BM-T700 to resist all loads in longitudinal and transverse direction.
Our Naval Engineering department assisted with the determination of ballast plans, verification of intact barge stability and determination of RAO’s. The drill string integrity during operation was verified with dynamic analysis.