Optical alignment projects Spring 2015 optical alignment

USCG Confidence, Tampa, Hendry Shipyard

Confidence, a 210' cutter, shown in drydock at the Hendry Shipyard in Tampa, Florida. The scale of the shafts is apparent, 11" and dwarfs the platform and the equipment. This job involved both reporting and working with the shipyard craftsmen and women at Hendry as some components of the drivetrain had to be renewed.

Optical alignment

A view of a target holder created for the specific bearing size on the ship. You can see soome signs of wear on the bearings, and the condition and wear patterns on the bearings can speak volumes about the condition of the drive train.

Uneven bearing wear

You can see wear on the left side of the picture, and marine growth on the right. The bottom of the bearing is also worn, but there is plenty of growth on the top. While it is fairly normal that the bottom of the bearing wears more rapidly, the propeller tries to climb out of the bearing so the wear, all things being equal, should show pretty similar patterns all around. When the wear and growth looks like this, the shaft is not passing through the bearing optimally. This may or may not be a performance issue as all ships are different and have different tolerances for misalignment.

Confidence in drydock

Shipyards in the morning, and finishing up the job at the beginning of everyone else's workday. I do these before daylight so the sun has had no effect on the shape of the hull, or the relationship of the critical components- reduction gear, struts, stern tube. And, I am always impressed by the Coast Guard men and women, their dedication and work ethic, their knowledge and enthusiasm, and above all their courage and dedication. They care deeply about their ship and their mission, and their professionalism and service are inspiring.