ABS Propeller Crack Testing

2014 July 2
by Chris Brown
Propellers before red dye testing

Propellers before red dye testing

We recently did a full 10-year ABS running gear survey on a 120 foot Benetti that we recently worked on. Routine maintenance on most running gear includes shaft straightening when required along with alignment and ABS crack testing on the propellers of the vessel.

A couple of years ago, ABS implemented a survey requirement when a vessel is hauled for propeller work. Sometimes ABS requires crack testing of the propeller after it has been torqued on the vessel. In this instance the surveyor only required crack test of the hun and tips while it was still in the machine shop.

Red dye penetrant applied

Red dye penetrant applied

Regardless of a vessel’s size, its propellers experience exceptional cyclic stress and fatigue. The stress can eventually result in cracks, both visible and microscopic. The fragmentation of a wheel while underway can have numerous consequences including the delay of a trip, damage to the vessel, or in rare cases, personal injury.

The red dye penetrant test is the preferred non-destructive procedure for crack testing a propeller. Depending on the volume of area to be tested, it usually can be completed within a few hours.

Although many yards or mechanics can apply dye penetrant and developer to a propeller, the skill, knowledge, and expertise truly exist in a technician’s ability to interpret the results. The ability to understand each nuance of a dye pattern can be the difference between unnecessarily replacing a propeller, or worse; not replacing one. Owners, captains, and engineers are wise to use only class ABS and Lloyds Certified Level II facilities for this procedure.

Our machine shop, Straight Line Marine is a certified Level II crack testing shop for running gear. Choosing the right facility with the right training and certification should be a top priority when going through an ABS survey or simply checking your props to make sure they are in top working order.


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