Replacing the prime engine in a seafaring vessel to meet modern emissions laws can be a major challenge. For many vessel owners, the option to retrofit existing engines is an attractive alternative to implement compliant power solutions into their operations. Recognizing the need to provide flexible, comprehensive solutions to help customers address the increasingly complex emissions regulations, Caterpillar unveiled the EPA certified Cat 3500 marine emissions kits. Bay Area tug and barge operator Harley Marine Services was eager to incorporate sustainable, efficient power solutions into their vessels and reached out to Cat Dealer Peterson to evaluate viable options for several vessels in their fleet.