Young Brothers Ltd., the state’s largest interisland cargo carrier, is raising its shipping rates 4.32 percent.

The company said in a notice Tuesday to its customers that the state Public Utilities Commission has approved the base price increase and that the effective date will be determined by the PUC.

On Wednesday, Young Brothers also announced that its fuel price adjustment would decrease to 3.46 percent from 3.78 percent. The new fuel adjustment went into effect Thursday.

“This is Young Brothers’ first significant (base) rate increase in six years,” the company said. “The decision enables our company to keep pace with increasing costs and to reinvest in the business after necessary capital expenses.”

Young Brothers, which will gain an additional $3.4 million in revenue, said the base rate increase is nearly two-thirds less than its original request of 11.05 percent and that it anticipates filing for another rate case later this year to give the company “greater financial stability in the face of steadily increasing operational costs.”

Young Brothers’ operations consist of six towing tugs, three harbor assist tugs, eight barges and other equipment, including generators, lifts, dry and refrigerated containers, and flat racks. The company said it replaced two of its six towing tugs in 2018 and will replace two more by the middle of this year.