Centa considered their Centaflex AGM coupling design but came up against a problem common to most marine gearboxes not designed with flexible couplings in mind; the oil pump was positioned very close to the output flange.

On the gearbox in question, the output flange is 7.25in diameter and only a coupling of 7.5in diameter would fit without fouling the oil pump. A 4in spacer would have been required to clear the pump while the manually clutched PTO and hydraulic pump required an even longer spacer. A spacer of such length plus the Centaflex AGM coupling would have been too long for the installation and would have upset the flexible mounting arrangement.

Consequently, a composite universal joint/Centaflex Series A cardan shaft was developed.

To achieve the required noise and vibration insulation levels, a flexible element providing a long articulation length allowed significant engine movement, to reduce noise and vibration without the need for additional spacers.

The vessel's designer was impressed. Dennis Davidson of Murray Cormack Associates said, 'Centa's coupling design achieved a very low noise level throughout the boat.'

MJ Information No: 19914