Office of Force Transformation,
San Diego, CA: Stiletto, the Office of Force Transformation's (OFT) effort to design and build a high-speed vessel made of composite materials for Special Operations Forces (SOF), is undergoing acceptance trials this month, after successfully completing builder's trials in February, according to the co-owner of M Ship Co., the boat's builder.
“We are very, very pleased with the way it's been going. We've already exceed 50 knots and we had the boat out in sea state four,” Bill Burns, co-founder and executive director of M Ship Co., told Defense Daily in a recent telephone interview.
Acceptance trials are being conducted off the coast of San Diego, and are expected to wrap up by the end of March.
Stiletto will make its East Coast appearance later this year for additional testing and possibly an excursion up the Potomac, Burns said.
“I was talking to [Rear] Adm.[ Don] Bullard who is heading up NECC (Naval Expeditionary Combat Command). We were talking about bringing [Stiletto] up the Potomac. He said it's the perfect environment to test that boat in because most of the waterways around the world are similar to the Potomac,” Burns said.
While the main focus of the effort, to build an 80-foot boat made of composite materials, has proven out, getting there is a “uniquely good story, too,” he added.
OFT challenged M Ship Co. to develop a new concept vessel to counter threats that current SOF boats couldn't meet, Burns said.
Not only did OFT want a new design, but a new design and development process, he added.
“The typical design process would start with doing preliminary design, some testing, evaluations…that can last up to five years from concept to getting something into the water,” Burns said. “Today you just don't have that time because if you start designing something for a threat you perceive today, I guarantee you in five years that threat is not going to be there.”
M Ship Co. was tasked with developing a new technology, which would include a new hull form, carbon composite construction, and OFT wanted to have something ready for evaluation in a year, he added.
The San Diego-base shipbuilder had never designed a military ship before, but the company has built ships for the America's Cup. Burns said the company used that model.
“It fit nicely with what we have done in the past, which is probably why OFT came to us,” he said. “The America's Cup model is a perfect model for this type of problem.”
Even with the company's efforts in developing racing yachts, there was still some risk, Burns said. For example, developing a ship without having 100 percent certainty that it is going to work out.
“We had to take some risk. We did and OFT accepted that initially. In fact we signed the contract before the design was complete,” he said.
Along the way, M Ship Co. adapted the design, changed the design, collaborated with organizations inside and outside the government, all to keep the effort on track, Burns said.
“At M Ship Co. we had a pretty good idea it would work. We felt confident, but we didn't have the resources that you typically have in a conventional project to evaluate how it is going to work,” he said.
For example, there are no modeling and simulation programs to help with the design.
“There are no tools that we are aware of that would allow us to accurately predict how it would perform, they simply don't exist. We are working with the government to develop tools to do that,” Burns said. “We had to go by some experimental testing we did on the water with our prototypes.”
Additionally, “the computational fluid dynamic codes are not created to handle this type of hydrodynamic phenomenon,” Burns explained.
“We ran into a lot of problems quite frankly, but because we developed this [mindset] of being collaborative, working with people both inside and outside industry, we were able to overcome them much more quickly and efficiently than if we had done it ourselves,” he added.
M Ship Co. didn't conduct tow tank tests either, Burns said. “It would take us one to two years to do a tow tank test and to interpret all the results.”
“We were actually able to get a full-size prototype in the water in that time period,” he added. “If we spent half the money doing a tow tank test to find out it may or may not work, those programs aren't always a guarantee. By spending a bit more money and saving a lot of time, we were able to get the boat into the water and know for sure whether it would work or not.”
Another challenge for the company was how to design the hull. “The hull shape is so different. It required us to do things differently from a structural standpoint and that wasn't anticipated when we started out,” Burns said.
The unique hull design was originally developed to minimize the wake from ships traveling in the canals of Venice, Italy. M Ship Co. was asked to address that problem, Burns said. Burns and his partner Chuck Robinson, soon discovered that their M hull design not only had a low wake, but provided high speed and increased efficiency. They eventually built a 38-foot prototype that caught the eye of the military and led to the development of Stiletto, Burns added.
Stiletto has a unique double M-hull configuration. It has four planning tunnels and two center-displaced hulls. The port and starboard skirts are independent of the hull and the centerline skirt is considered non-structural. The design allows for the wave dissipation on each side of Stiletto. Wake energy goes up into the planning tunnels and air gets fed into these tunnels and creates dynamic lift that causes the boat to ride on air and froth water. And because it's using all the energy of the displaced wake, Stiletto has a very low wake signature on the back end (Defense Daily, May 4).
“Because of the shape of the tunnels, we had questions about how to build the part and incorporate enough strength into the tunnels so we [wouldn't] have a problem with the boat on the water. If you look at the hull shape the boat is very wide and very shallow. We were concerned the load at the bottom of the boat would be a problem structurally,” Burns explained. “We ran some tests on the boat and actually came up with creative structural solution that hadn't been done before. Parts of the boat are actually designed to move, to be flexible. Because parts of the boat can move a little bit, it will actually smooth out the ride.”
The company has developed M-hulls for commercial boats, but even those are one-of-a-kind, he added.
“We did a single M before, we have a prototype of the single M hull, and that boat has performed very well,” Burns said.
M Ship Co. has demonstrated the single M hull vessel for military officials who wanted to evaluate whether the company could scale up the concept to a larger size.
“In order to do that, our theory was we could combine two of these M hull shapes together side by side to preserve the dynamic lift effect we would get from the tunnel and be able to carry a much bigger load,” Burns added.
“This hull form is unique and offers a lot of opportunity for different sized boat. I think you can actually scale it up much beyond the 80-footer to 200-foot size craft and you can scale it in the other direction down to a 40-foot patrol boats or even a USV [unmanned surface vessel]. It has the ability to transcend size and is very scalable,” he said.
One feature of the boat is its shallow draft. With the Navy looking at how to maneuver in the littorals and riverine areas, being able to bring an 80-foot or 100-foot craft into 3-feet of water is “something pretty unique, pretty unusual,” Burns said.
“The riverine force is interested in exploring what we might be able to do. The stability of design for a small craft like a USV is very intriguing to a lot of people who are looking into this area. Because you have a very stable platform, when you have instruments or weapons on a platform you don't want them bouncing around you want them to be stable,” he added.
One of the bigger problems M Ship Co. ran into had nothing to do with the hull shape or Stiletto's design; it was with the government, Burns said.
When the company wanted to charge ahead with some ideas, and implement them, the government, because of its aversion to risk wouldn't allow it, according to Burns. “The government has such a culture that's adverse to risk, and I think it's a real problem.”
“To be able to manage and develop new concepts within the government you need to change the culture because there is no incentive now for designers or managers to take any kind of risk at all. In fact, it's the opposite, if you take risk you are punished,” he said. “That was a challenge for us. I think it's a cultural issue in the government. There are some areas where you need to mitigate the risk as much as possible, but as far as developing new ideas and new concepts you need to be able to take a risk to have a breakthrough.”
