Crownblock Overhaul

We had a crownblock in, which was completely overhauled. That meant that some parts have been replaced by new, and other components are reused. All parts are checked again on the standards/certifications valid on the rig.

A crownblock is a pulley at the top of the derrick and pulls the pipes after drilling upwards. This consists of a cluster, a deadend and a fastline. Below you can see the photo shoot and see how this overhaul was processed. The client was under time pressure and with our flexible team, we could complete this project within 5 days.

The cluster

(First part of the photo report, five discs in a frame)
After the cluster was loaded off the truck and secured on the floor of the workshop, the sheaves and bearings were removed one by one. From this cluster we had the sheaves in stock and they could be used immediately. The sheaves we have in stock had been previously overhauled & recertified. The peddestols were blasted, checked for cracks (MPI) and then coated. Subsequently, the new sheaves were placed on a new checked, shaft. Each sheave was provided with new bearings, and a grease seal so the grease would stay in the bearings. After placement of the sheaves, the opposite side of the frame was placed on the cluster and the bolts were torqued. Finally, the shaft was again pumped with grease.

Deadend & fastline

(Second part of the photo shoot)
These two units were blasted out, after the sheaves were removed. After blasting, we MPI’ed the peddestols. When approved, they could be metalized (coated with a zinc coat, making it no longer affected by rust) and coated. In our workshop subsequently, we placed the new bearings by nitrogen in the sheaves. These sheaves were in stock. After both bearings had sufficient grease in the sheave and put down with a seal, they could go in the frame on the new shaft.

More about About Allrig, the offshore and onshore specialist

Go to the contact page of our website, or send an e-mail to:

Stay in touch

Sign up for our newsletter