January 08, 2007
Experimental Stiletto takes advantage of travel delay
M-hulled ship undergoes more tests
By Gidget Fuentes
SAN DIEGO — When its ride to the East Coast fell through in late summer, the experimental ship Stiletto did what any California native would do: It stayed and played on the water.
The innovative ship was slated to depart San Diego for Norfolk, Va., for another round of at-sea tests and demonstrations starting this fall to further understand the capabilities of its carbon-fiber, M-shaped hull.
But after its scheduled ride on a transport ship fell through, program officials kept the high-speed Stiletto in the water.
The 80-foot-long, 40-foot-wide ship, built with the concept of launching and recovering Navy SEALs and other special operations forces closer to their targets, wrapped up nearly six months of tests and sea trials in late August and began preparations for shipment to the East Coast.
But the barge slated to carry it to Norfolk, where it would begin another series of tests, evaluations and demonstrations along the mid-Atlantic, was delayed. So the gray-hulled Stiletto, awaiting transport rescheduled for early January, remained on the water in San Diego and went back to work. Its uniquely shaped silhouette, with a wide, M-shaped hull that looks like Batman’s call sign, catches eyes of boaters and tourists along the San Diego Bay waterfront.
The delay “gave us the opportunity to do some more testing,” said Bill Burns, executive director of M Ship Co., a San Diego-based ship design firm that crafted the unique hull form and built Stiletto along with local yacht builder Knight & Carver for the Defense Department’s Office of Force Transformation.
“The more time we can put in the boat, the better” to evaluate how the hull performs in various sea conditions, said Burns, who developed the M-hull technology. The program is funded through 2007, he said.
For the past four months, ship designers and engineers have been studying Stiletto, which is powered by four 1,650-horsepower diesel engines that propel it to speeds of 55 mph or more. The vessel can cut 360-degree turns in two boat lengths. It’s designed with an “electronics” keel that integrates a local area network and enables “plug and play” sensors and systems for commanders and underway spec-ops teams.
Stiletto’s hull, with curvy planing tunnels that displace the energy of waves and lift the vessel off the water, is one of its key features being closely evaluated at sea.
“Some people call it the ‘Magic Carpet Ride,’” Burns said.
The hull shape is designed to reduce friction in the water and cushion impact as the vessel carves through waves and swells, more so than other watercraft, such as the Mark V spec-ops craft used by Navy special warfare combatant craft crewmen and SEALs. “It is a planing boat and it is on top of the surface, but you would have not the boat slamming” as other hard-hulled boats, such as the Mark V, he said. “It was designed to dampen those slams.”
The hull also gives Stiletto its signature wake, a thin frothy mix of seawater; even at speeds of 40 or 50 mph in a channel, the ship leaves a barely discernable wake in its path. “Stiletto is designed to capture the bow wave energy,” he added.
The extra time for testing gave designers and engineers a better idea of the wake and the hull’s performance in rougher seas and higher speeds.
It was good news, Burns said. “With Stiletto, the faster it goes, the smaller the wake is,” he said. “It’s exactly the opposite” of catamarans, whose wakes grow at higher speeds.
While operating in the Pacific at sea state 3 — slight winds and cresting waves — “there’s not a big difference with going 49 knots offshore with a [rigid inflatable boat] in its bay,” he said.
At sea state 4 — with moderate winds and breaking waves of three to five feet — “we were able to do 40 knots in the conditions running parallel to the swell,” he added.
More payload and wake testing in the Atlantic will look at how Stiletto performs when slicing into swells with operational loads. Once on the East Coast, Burns said, the ship will encounter more of the Atlantic’s “short chops,” which will give it a different operating environment than the Pacific’s longer period swells, he said.
On the East Coast, Stiletto, which might make a trip up the Potomac River to Washington, will be able to showcase the benefits of its technology, including its spec-ops capabilities as well as the benefits of its small wake on coastal harbors and facilities. While operating in San Diego’s shallower southern bay one day, “the depth finder was reading 3½ feet,” Burns said. Stiletto’s draft is 2½ feet.
“As the military focuses more on littoral and riverine environments around the world, they have the responsibility not to damage piers and docks,” he added.
Now that looks cool as crap!
Wait - let be grab my ski. I wanna cut a Rooster tail behind THAT baby!