New, powerful water jets installed on the Golden Gate Ferry M.V. Mendocino intended to propel the vessel forward instead send it in reverse, because the system spins in the wrong direction.

The $500,000 gaffe means the return of the high-speed ferry to Larkspur will be delayed until next spring, and patrons will continue to see the smaller M.V. Del Norte for service. The ferry was to have returned this winter after a $6 million overhaul since being removed from service in April.

“The ferry was put in the water for sea trials and it did not perform as expected,” said Priya Clemens, spokeswoman for the ferry district. “The boat went backwards instead of forward.”

The mistake was discovered in early October in the waters off San Diego, after work by the Marine Group Boat Works in Chula Vista, although that company bears no fault.

“The water jets spin in the wrong direction,” reads a report on the matter from ferry officials, noting it sucks in water. “Needless to say, this appears to be a major engineering failure.”

Golden Gate Ferry officials are laying the blame squarely at the doorstep of Australian-based Incat Crowther Ltd., the original designer of the ferry, which also provided the design for the replacement of water jets and the gearbox. Incat Crowther officials could not be reached for comment Monday.

Ferry attorneys have been in touch with the company, but they say it’s too soon to know if it will accept responsibility, or if the matter will have to be litigated.

In order to get the boat back on San Francisco Bay sooner, ferry officials will ask the Golden Gate Bridge district board this week to approve a half-million-dollar fix — money the district would seek for reimbursement from Incat Crowther. The money for the repair would come from federal funds the district already has.

The high-speed ferry is one of the workhorses of the fleet, plying the bay between Larkspur and San Francisco daily delivering thousands of passengers to and from work.

The larger overhaul work includes the replacement of all of the seat covers and the entire ceiling, as well as a portion of the flooring and paneling, and a hull extension. Federal funding is paying for 80 percent of the work, district funds 18 percent and state clear-air funds account for 2 percent.

The “Mendo” was delivered to Marin with much fanfare in September 2001 at a cost of $8.5 million, joining the 400-passenger M.V. Del Norte in the district’s high-speed fleet at that time. The fast ferries make the Larkspur-to-San Francisco trek in 30 minutes, 15 minutes faster than the slower and larger Spaulding class boats.

Prior trouble

This is not the first hiccup for the 141-foot, two-deck, 450-passenger, catamaran. A year into service, maintenance workers discovered aluminum used to build the ferry’s hull corroded more quickly in seawater than expected.

Nichols Bros. Shipyards in Washington state built the ferry. The problem occurred when an aluminum plant sent Nichols Bros. the faulty material. That plant had changed its manufacturing process, which altered the composition of the aluminum, Nichols officials said at the time. Normal aluminum holds up for 50 years and beyond, but the aluminum used in the Mendocino would last only about 20 years, bridge officials were told.

The Mendo was shipped back to Washington state for repairs in December 2002. Those repairs were expected to take three months, but the work was more intensive than first believed and took about a year.