Conrad's aluminum manager Todd Babin shows the "tweaked" props.
The 300-ton travel lift at Conrad Industries Morgan City facility is a major attraction to Gulf Coast crew boat operators. Shallow waters in the area add to the heavy usage that crewboats receive contributes to a steady demand for quick haul outs and timely below waterline repairs. The yards large upland area is another attraction as it provides ample storage space for vessels undergoing major overhauls.
This latter is the case with a series of six vessels recently acquired by Seacor Marine
as part of their larger take-over of the Seabulk fleet. The six crewboats were each powered by four electronically controlled 1100 hp two-cycle engines turning at 2100 RPM that were getting only about 6000 hours before requiring a rebuild.
Seacor decided to repower the vessels with Cummins (CMI)
KTA38 M1 engines that deliver 1100 hp at 1800 RPM. According to Seacor project manager Joe McCall, these engines will routinely deliver 25,000 hours between rebuilds.
The repowers presented some challenges however. The smaller diameter shafts on the vessels would not handle the larger diameter props that the higher torque of the Cummins engines will deliver. To allow for this, explained Joe McCall
, “We decided to tweak the props and turn the them faster so we have gone with a 2:1 reduction rather than the 2.36 and 2.55 reductions on the old 2100 RPM engines. Two of the boats had one reduction and the other four had the second.
In June the Seabulk St. Tammany was undergoing the first change out of her four engines. The job will to be completed by the end of July with the other five boats scheduled over the coming months.