Umbilical Reeler and Power Sheave


Denith Engineering designed, manufactured and commissioned this 3 Ton 275m Umbilical Reeler and Power Sheave for a 178mm Umbilical for installation on board the mv Mafuta. The new reeler and sheave will replace the existing umbilical reeler and sheave.

The new units needed to be complete and incorporate all required hydraulic, electrical, instrumentation and control subsystems and components in order to fit seamlessly onto the existing mounting arrangements and tie into the existing launch and recovery and associated systems.  

The umbilical and hydraulic rotary joints were part of this design scope and were free-issued by client for assembly and integration prior to installation on the vessel.

Umbilical Reeler

The umbilical Reeler comprises the following main components:


Drum manufactured from pipe sections and steel plate with central stiffened mounting plates for mounting the slew rings, the rotary joint and the slip rings and complete with internal access.

Support Structure

Support structure manufactured from steel pipe and plates arranged to accept the slew ring mounting plates, access ways and spooling structure. The assembly is arranged for mounting to ship structure.

Bearings and Drive

The non-drive side bearing is a slew ring with one side mounted to the drum and the other side mounted to a stiffened floating plate, which is mounted to the support structure. The drive side bearing is a geared slew ring with the rotating section mounted via a spigot to the drum end plate. The stationary side is mounted to the manufactured gear box. Two pinions each mounted on two bearings are fitted to the box. The pinions are driven by torque arm mounted gearboxes and fixed displacement hydraulic motors fitted with disc brakes. 


The spooling device is mounted above the winch and comprises of two single pitch threaded shafts with phosphor bronze nuts actuating the carriage. The rollers are manufactured from schedule pipe and mounted on spherical roller bearings. The drive is effected by a directly mounted hydraulic motor to one shaft and a chain and sprocket system to the other. An absolute encoder is fitted to the chain driven shaft which communicates with the reeler drum absolute encoder.

Power Sheave

The power sheave comprises of the following main components:


Sheave manufactured from steel plate and hollow bar, that is rubber lined and split for transport and assembly.

Support Structure

Support Structure manufactured from schedule pipe and plate sections. 


The drive comprises a hydraulic motor, disc brake and torque arm mounted gearbox directly coupled to sheave shaft.

Pinch Roller

Manufactured from steel with bonded rubber tread. This is mounted on a swing arm and actuated by a hydraulic cylinder.

Roller Box

Manufactured from steel plate and with HDPE rollers and arranged for mounting on a swing arm.

Leave a Reply