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Frequently Asked Questions About IsoFlex Couplings

If you have further questions please contact the team at PDL for more information.

Can an Isoflex coupling take any form of mis-alignment?

NO - an Isoflex coupling is designed as a vibration dampener only! Any angle / offset misalignment will damage the Isoflex coupling.

How important is the alignment procedure?

This is extremely important to the life of an Isoflex coupling. The gearbox output flange and shaft half coupling must be within .003" in face to face angle. The flanges must NOT be offset in any way i.e., vertical or horizontal.

Can alignment be achieved when the vessel is out of the water?

NO - a temporary procedure can be done but the alignment needs to be checked and completed when the vessel is in the water loaded in max running trim.

Can the Isoflex coupling be used in the alignment procedure?

NO - due to it's Polymer form it is not consistent enough to gauge true alignment. If the two flanges cannot be brought face to face then a steel dummy that reflects the outer dimensions of the Isoflex must be used.

Can an Isoflex coupling deform under load?

Yes - but only due to misalignment either at rest or when max thrust is applied to the engine - which can dramatically alter the true alignment if the engine mounts are to soft.

How do I know which Isoflex coupling is correct?

Isoflex have a vast range of couplings that are individually rated to a particular gearbox. Henley’s staff can make this selection.

Can I simply bolt the coupling in place after the alignment procedure has been completed?

Yes - however Isoflex require a certain sequence and torque which is stated on the installation instructions.

Do I use locktite type product on the bolts?

NO - use anti-seize grease, the bolts are supplied with spring washers.

: Is there a "Get home" procedure if the coupling fails due to impact damage on the drive line?

Yes - if the driveline has been set up correctly the gap between the fwd end of the prop boss and the aft end of the strut will be greater than the width of the Isoflex - so when in trouble the Isoflex can be removed and the flanges hard coupled as a temporary option. NOTE if a rope cutter is installed on the shaft then a spare steel replica or another spare Isoflex coupling needs to be fitted.