A 12-year Navy program to develop six minisubs for commando missions has been canceled after a $446 million investment, leaving the one and only sub at Pearl Harbor with an uncertain future.

With an original estimate that a single sub would cost about $80 million, the price tag for the one vessel that was delivered is $366 million above projections.

The 65-foot Advanced SEAL Delivery System, or ASDS, was heralded as a "transformational leap ahead" and was intended to deliver commandos dry and rested to a point of departure — rather than in the current underwater vehicles that are open to bone-chilling cold water and require the use of scuba gear.

But after years of battery, noise and propulsion problems, the Pentagon canceled the Northrop Grumman project on April 6 because of performance and reliability concerns, the Navy said.

An "improvement program" will be pursued for the sole ASDS, based at a SEAL Delivery Vehicle Team 1 facility on Pearl City Peninsula.

U.S. Rep. Robert Simmons, R-Conn., whose state includes sub builder Electric Boat, has railed against the Northrop Grumman effort at congressional hearings while suggesting the program be re-bid.

"It worries me greatly that the Advanced SEAL Delivery System, which is something our special operations forces drastically need, is 700 percent over budget, 12 years behind schedule and still hasn't delivered a workable first SEAL delivery system," Simmons said in March.

At the current rate of expenditure for the minisub, "you could build it out of 14-karat gold," he said.

John Pike, director of military think tank GlobalSecurity.org, said it is puzzling that the program was allowed to limp along so long.

"It has not been a shining moment," Pike said.

Neither U.S. Rep. Neil Abercrombie nor U.S. Sen. Daniel K. Akaka, both Hawai'i Democrats, was available for comment yesterday.

Designed to ride piggyback on the Los Angeles-class submarines Greeneville and Charlotte, both based at Pearl Harbor, the boxy, 8-foot-diameter ASDS is designed to sneak up close to shore with two crew and up to 16 SEAL (Sea, Air, Land) commandos.

Its skin is the material used on Stealth fighters, it can take and transmit pictures almost in real time, and its design allows for long-range operations.

DRY TRANSPORT

One of the minisub's biggest advantages is that it keeps commandos dry before they exit the sub. Existing SEAL Delivery Vehicles are convertible-like craft launched from "dry deck" shelters on larger submarines that expose troops to energy-sapping cold water long before they reach their final destination.

The Navy in 2004 celebrated the completion of a $47 million waterfront home for SEAL Delivery Vehicle Team 1 on 22 acres at Pearl City Peninsula that includes a 326,000-gallon freshwater test tank.

At the time, the team had 45 officers and 230 enlisted personnel — 93 of them SEALs.

Five Hawai'i-based SEALs died in connection with an ill-fated reconnaissance mission and failed rescue last June 28 in the mountains of Afghanistan.

ONE DEPLOYMENT

The Navy in July 2003 took delivery of the first ASDS, and it rode piggyback on the 360-foot Greeneville during a deployment to the Persian Gulf by Expeditionary Strike Group 1.

The entire program, including six minisubs and facilities in Hawai'i and Little Creek, Va., was to cost $527 million. According to the Richmond (Va.) Times Dispatch, the subs originally were expected to cost $80 million each.

Lt. Cmdr. Steve Mavica, a spokesman for U.S. Special Operations Command in Florida, said that in November, the decision was made to restructure the ASDS program. Investment in hulls 2 and 3 was canceled.

More recently, the remainder of the program was canceled.

A March 31 Government Accountability Office report on ASDS said that silver-zinc batteries were replaced with lithium-ion versions, and an aluminum tail was replaced by titanium.

Acoustic or noise-level problems — a critical issue for submarines — were "being addressed," the report said.

In earlier tests, a propeller was the source of the most significant noise, and a new composite propeller was added.

In October 2005, meanwhile, the ASDS experienced a propulsion-related failure, and the Navy decertified the ASDS from operational test readiness, the GAO report said.

"While the performance of ASDS-1 has been generally satisfactory, the overall reliability is still a concern," Mavica said. "Given the importance of the mission and the need to ensure the safety of our personnel, (Special Operations Command) and the Navy must be completely confident in the reliability of the craft."

COSTS UNJUSTIFIABLE

Debbi McCallam, a Northrop Grumman spokeswoman, said vibration, noise and battery problems were identified, addressed and fixed last summer. McCallam said the rationale for the recent cancellation was based on the prospect that keeping the future boats in the program might cause a breach of the Nunn-McCurdy law, which requires the secretary of defense to certify that programs with a 25 percent cost increase are necessary for national security.

McCallam said Northrop Grumman is involved in a $69.4 million ASDS-1 improvement plan, and Special Operations Command could resurrect the larger program. "Of course we'd like to begin construction of the next vessel as soon as possible, since we've got the history and expertise," she said.

Reach William Cole at wcole@honoluluadvertiser.com.