HOW DOES MANECRAFT WORK?
The Manecraft seal comprises two main components: the stationary seat assembly and the rotating seal assembly, both moulded from tough, oil resistant chloroprene.
The stationary seat has a solid bronze ring bonded into it and is clamped onto the sterntube with two stainless clips, this part remains stationary.
Incorporated into the stationary seat is a red emergency sealing clip. This safety feature is for emergency only and is protected by a tamper proof tag. Under no circumstances should the shaft be rotated whilst this clip is tight.
The rotating seal assembly is clamped onto the shaft whilst being compressed against the seat. As the shaft rotates, so does the seal assembly.
The sealing face rotates against the stationary bronze seat, lubricated and cooled by the water inside the seal, and a water flush.
An air vent is incorporated in the flush system (see fitting instructions). The bearing spacing must be determined from the thrust bearing to the ‘P’ bracket bearing. Please refer to the bearing spacing section for further information.
Manecraft seals are easy to fit and are direct replacements for old style propeller shaft packed glands. They do not require packing, adjusting, or maintaining and cannot wear a groove in the shaft. Following careful installation, all they need is a quick regular inspection in common with sea cocks, hoses, and other hull fittings situated under the water line.
On monitored test vessels, Manecraft seals have completed in excess of 10,000 hours of service, or 100,000 sea miles and are still in perfect condition. On most vessels, age will be the deciding factor rather than service hours when renewal is necessary. With the low cost involved, replacement of such an essential component every fi ve years is recommended.
The Manecraft seal is simple to fit. Most vessels are easily converted to Manecraft and while there are many types of stern gland, they generally fall into three styles.