HONOLULU -- The Hawaii Superferry has been out of service since Sunday because of bad weather, but the company confirmed on Wednesday the ship needs repairs.

Hawaii Superferry officials confirm there are "surface cracks" involving two "auxiliary rudders" on the back end of the ship.

The Coast Guard told KITV that inspectors discovered the crack during a routine maintenance inspection on Monday.

The Hawaii Superferry canceled all voyages to Maui Sunday because of bad weather and it has not sailed since.

Now, the Superferry confirmed inspections performed while the ship was dockside uncovered the surface cracks.

"The Coast Guard was notified Monday concerning hairline cracks to the Superferry's rudder housing," Chief Petty Officer Chad Saylor said.

Superferry officials declined on camera interviews, but said the vessel's two auxiliary rudders are rarely used. They said the rudders serve to make only slight course adjustments. The Superferry's four jet drives in the rear of the ship serve as the primary steering mechanisms, they said.

The Coast Guard said the rudders also serve to stabilize the ship.

"The investigator determined that the vessel wasn't in compliance due to these cracks," Saylor said. "These cracks need to be repaired before the vessel can sail safely."

Neither the Coast Guard nor Superferry officials could describe the cracks, how many there are, what may have caused it or how long they may have been there.

The repairs will be made on Thursday and an engineer will inspect the ship before it resumes service, Superferry officials said.

"That engineer is assisting the Coast Guard to make sure that all the safety regulations are met before it can sail again," Saylor said. "A final determination will need to be made, whether or not they can take passengers onboard again."

Superferry officials maintained it has been out of service because of the weather. The company plans to resume service to Maui on Friday weather permitting.