Alakai: New hulls on ancient waters

, Alakai departing Kahului, on Maui, for the return trip to Honolulu. The 350-foot ferry was built by Austal in the United States. Powered by four 11,000-hp MTU diesels, the ferry can cruise at 30 knots.

Naturalist Charles Menzies, on one of Capt. George Vancouver’s early Hawaiian voyages, noted that the largest canoe in the islands was built from a log that had drifted across the Pacific from Oregon. More recently, the largest passenger vessel on the island also came over from the mainland.

Hawaii Superferry’s ship, Alakai, was built in Mobile, Ala., to an Australian design. In modern times as in ancient times, mariners choose the best designs and the best materials available.

Built by Austal at its U.S. plant, the 350-foot by 78-foot ferry carries approximately 200 cars using the retractable mezzanine deck or a mix of cars and trucks when using only parts of the retractable deck. The passenger deck lounges can handle as many as 800 passengers. By any measure this is a big vessel and it took a lot of power to move it on its voyages between Oahu and Maui.

Professional Mariner visited Alakai before a state court ruling in March 2009 forced Hawaii Superferry to cease operations. The judges decided that a state law should not have allowed the company to begin ferry service before an environmental impact statement had been completed. The ruling left the long-term future of Hawaii Superferry and Alakai in doubt.

Because a chain of volcanoes forms the Hawaiian Islands, the inter-island run differed from most coastal island routes in that the waters plunge to extreme depths just offshore. In the immensity of the Pacific Ocean, specks of land are open to the long swells even in the best weather. The islands provide some shelter, but they can also funnel the winds and build huge seas. To reliably schedule a passenger ferry in this locale requires good equipment and good operators.

Capt. Craig Campbell (foreground) is assisted on the bridge by Chief Officer Ryan Hopkins.

The name Alakai, or “ocean path" in Hawaiian, was chosen to honor the ancient Hawaiian navigators. Alakai’s path between Honolulu Harbor on the island of Oahu and Kahului Harbor on the island of Maui had three legs. The first leg out from Honolulu took the vessel across the open Kaiwi Channel where there is usually a good-sized ocean swell running. On a typical summer day, the ferry maintained a higher speed around 28 knots as the automated active motion control system, employing T-foils forward and interceptors aft, works best with a little more speed on. Alakai is designed to cope with 20-foot seas, but company policy limited operations to 15-foot seas for passenger comfort.

On the bridge, captains Craig Campbell and Adam Parsons spelled each other off in the starboard side operator’s seat while Chief Officer Ryan Hopkins occupied the port side seat. Chief Engineer Christian Yuhas controlled the port and starboard engine rooms from his seat at a console just behind the captains. An additional watch was kept from the bridge wing by able seamen who rotated every hour. The atmosphere on the bridge was one of calm focus. Exchanges between the navigation officers and the engineering officer were repeated to assure clarity. A second engineer worked with his chief to visit below-deck engine spaces to physically check data. When engineers carried out routine maintenance in the engine room, Yuhas followed their movements by video monitor.

Above, the four MTU 20V8000 M70 engines power Kamewa 125 SII waterjets.

The evening before, Yuhas had checked out the engine room himself while Port Engineer Kent Able gave an engine room tour to Tom Katica, ZF Marine’s Seattle-based account manager. Katica had worked with the ferry company in the original selection of the ZF transmissions that link the four 11,000-hp MTU 20V8000 M70 main engines to the Kamewa 125 SII waterjets. Now he was back for a follow-up visit to see that all was operating as it should and to get an update on the second ferry that was being built at the Austal yard in Mobile. In a time when vessels may be designed, built and operated in three locations — all separated by thousands of miles — this sort of followup and coordination is essential. The gears selected in this case, four ZF 53000-2 horizontal offset non-reversing transmissions, are linked to the engines with Geislinger Gesilco fiber composite couplings that have a dual carbon membrane to provide capacity for compensating misalignment in radial, axial and angular directions. As with similar installations on other Austal-built ferries, the couplings also compensate for movement resulting from the flexible engine mounts.

As Alakai completed the crossing of Kaiwi Channel and entered Kalohi Channel between Lanai and Molokai Islands, the vessel motion from the ground swell lessened. There was a 20-knot wind, but the islands gave a shorter reach and the seas were reduced. The captain asked Chief Yuhas to bring all four engines down to about 785 rpm. At this rpm, the engines use only two turbo chargers rather than four as they do at the higher rpm. The result was a slower speed, just over 23 knots, but much reduced fuel consumption — down to a burn of 160 gallons per hour from 340 at the higher rpm.

The ferry can carry 200 cars.

Coming into the Kalohi Channel also brought Alakai into the whale-protected area. Between Jan. 1 and April 30 is the season when whales are most likely to be in this channel and a particular set of rules apply. The ferry needed to stay on a track that kept it in the deeper water where possible. Two dedicated lookouts watched for whales. If one surfaced in front of the boat, the vessel was to go into an immediate stop. Because this trip was in the off- season, they could navigate to save on fuel. Every mile shaved from the 180-mile route translated into significant fuel savings.

A pair of Current Corp.’s Night Navigator 8540, an intensified night-vision system, was installed on Alakai during construction. For the winter whale season of 2009, a dedicated aid to whale avoidance was added. Researchers at Vancouver-based Current Corp. have developed the Night Navigator 3 with the ability to detect the temperature variations in a whale’s spout. This piece of equipment uses high definition and image intensified cameras along with thermal imaging technologies. Two of the gyro-stabilized devices were installed to port and starboard above the bridge of the catamaran. The same device has been installed on Seacor Marine’s catamarans Cheetah and Cougar, as well as two Canadian Coast Guard hovercraft.

Their development and testing included researchers creating an artificial whale spout that demonstrated the technology could detect .69 quart of water at up to 1.25 miles away. Further tests entailed the temporary installation of the device on a Celebrity cruise ship on the Alaskan route.

As Alakai approached Maui, the track line required a course change to go out around the north tip of the island and then turn south into Kahului Harbor. Capt. Adam Parsons was on the delivery trip that brought the ship from Alabama through the Panama Canal and up the cost to California before crossing over to Hawaii. To conserve fuel they traveled at about 22 knots on that voyage. “We actually would have had enough fuel to come straight to Hawaii from Panama," he said.

As the ferry made the turn northeast into Pailolo Channel, the vessel pitch began to climb. Parsons went to the ride control system. This highly intelligent system can be adjusted to control pitch or roll. To control pitch the T-foils work in unison whereas to control roll they work in opposition. Adjustments include both gain and bias. The gain adjustment determines how aggressively the system will work to reduce pitch and/or roll, but the more aggressive it is set the more fuel the boats will burn to maintain speed. The bias determines the percentage between pitch and roll. In relatively calm waters like the Pailolo Channel the gain was set low. The aft mounted interceptors, which are part of the automated ride control, were employed to adjust the vessel trim to be down at the bow, increasing speed and fuel efficiency.

As the ferry moved out of the shelter of Molokai and approached Nakalele Point on Maui’s north end, vessel speed was brought back up to 26.9 knots and the ride control system was adjusted. With a course heading of 90 degrees and Nakalele Point to starboard, the system was set with a 60 percent bias to control pitch and a 40 percent bias to control roll. “In winter we will actually tack to avoid hull slap," Parsons said on this leg of the voyage. Then as Alakai rounded the point and the course was set to 120 degrees and the swell moved to quarter the port bow, the system was adjusted to give an 80 percent bias to roll and only 20 for pitch. Five minutes later, Parsons said, “OK, Chief, come up to eight." This translates to just under 1,100 rpm and 30.7 knots.

Given the precision equipment from the big MTU diesels to the ZF gears and Kamewa jets, as well as the supplemental systems like ride control and passenger service, the piloting of Alakai seems to share more with a passenger jet than a tug or containership. When moderate speed adjustments can result in substantial savings per round trip, the role of the operators was as essential as that of the ancient Hawaiian navigators of these same ocean paths. •

By Professional Mariner Staff