At one time, the notion of powering a workboat with waterjets was approached with more than a bit of skepticism by workboat operators, especially those building boats in the smaller ranges. Those were hands-on outfits steeped in the tradition of shafts and props. But by the late ’90s and early 21st century most of that reluctance had pretty much disappeared.
“We are well past the voodoo stage,” is how Steve Peake with HamiltonJet puts it.
Thus you can have a 20' oil-spill response skiff for Alaska’s Cook Inlet Spill Prevention & Response with a single TraktorJet TJ457HT from NAMJet built by Bay Welding Services in Homer, Alaska. At the other end of the scale you can have four HT900 waterjets from HamiltonJetemerging from the transom of a 230' (70 meter) Incat Crowther-designed catamaran crewboat/fast supplier being built at Incat Tasmania that will operate in the Caspian Sea.
HamiltonJet’s Tony Kean wrote in an email that the Australian-built crewboat will be “the world’s largest high-speed crewboat operating in the global oil industry.” It is also the largest boat that HamiltonJet has put its jets on.
The DP-2-classed crewboat is capable of carrying 150 passengers, 14 crew and 200 tons of deck cargo. The expected top speed is 36 knots — 30 knots loaded — with each jet powered by a 3,862-hp (2,880-kW) MTU diesel.
Prior to outfitting the crewboat for the Caspian Sea, the largest boat with HamiltonJet waterjets was the 225' Ms. Netty, built by Louisiana-based Gulf Craft for Gulf Offshore Logistics.
In the U.S., the crewboat market is a driving force for much of the waterjet development. “I suspect it’s the hottest thing going at the moment,” Peake said, adding that it was the crewboat market’s need for larger boats that was a major factor in the designing of the HT900 waterjet, along with the HT800 and HT1000. “There’s always been a phenomenon with crewboats where they prefer to stay with a supplier. Sometime when boats get bigger you run out of range and, consequently, new jets get developed.”
HamiltonJet and Rolls-Royce Kamewa have been major players in the U.S. Gulf crewboat market. Another waterjet manufacturer that is just breaking into this market is Marine Jet Power (MJP), a Swedish company with U.S headquarters in Columbus, Ohio. MJP acquired the Ultra Dynamics line of waterjets in 2012.
MJP normally supplies military and government boats with waterjets, but in April, the first of a pair of MJP-propelled 175' crewboats will be launched at Swiftships Shipbuilders in Morgan City, La., for Rodi Marine in Lafayette, La. The second one will go into the water a few months after that. The DP-2 crew and supply boats will have four MJP 650 CSU jets giving the boats a top speed of 31 knots.
“It’s the first big market we’ve seen,” said MJP’s Jordan Tilton, adding that MJP jets will also be going in “smaller 12- to 13-meter crewboats. We are starting to enter the Gulf market. We’ve wanted to be there for a long time.”
MILITARY MIGHT
A rapidly developing market for waterjets is the military. The biggest program Rolls-Royce has going now is supplying jets for the U.S. Coast Guard’s 45' response boat-medium (RB-M) program, said the company’s Jonathan Webster. The 49-mph boats are being built at Kvichak Marine Industries in Seattle and Marinette Marine Corp. in Green Bay, Wis. When the program is finished, 170 boats will have been built. As of December, 144 RB-Ms had gone in the water.
At the top end of the size spectrum, Rolls-Royce is outfitting the new Freedom-class monohull littoral combat ships for the Navy. Each 450' vessel has four Rolls-Royce MK1 waterjets giving them a speed of about 46 mph. While developing the thrust to move the vessel at that speed, each jet is moving almost 500,000 gals. of seawater per minute.
A company that by its own admission is just starting to emerge from the shadows of the jet-propulsion industry is NAMJet. (The Benton, Ark., company was called North American Marine Jet until it was purchased by Australia’s Birdon in 2011.)
Manufacturers of high-thrust, low-speed waterjets, NAMJet is currently in line to supply its 15" TJ381 waterjets for a new fleet of 30' bridge-erection boats for the Army. The twin-jet boats will be built at Oregon Iron Works in Clackamas, Ore. The initial order is for 18 boats, but it could end up being many more.
“We met or exceeded all the performance specs of the Army,” said NAMJet’s Phil Organ. “The strongest was for thrust, which is paramount for pushing bridge sections around.”
When you are just emerging from the shadows of the bigger guys, it doesn’t hurt to be innovative. That’s what NAMJet did two years ago when faced with the problem of fitting two jets in small seismic boats with a narrow beam and 22° deadrise.
Initially, the builders “couldn’t fit the jets together. They were overlapping and interfering with each other,” said Organ. NAMJet’s solution was the TwinPak Jet. NAMJet basically built a section of the hull — including that steep deadrise — and inside it set two TJ431HH jets.
“We had to do a little trimming here and there,” noted Organ.
The package was sent off to the builder who lifted it in place and mounted it in the hull. “We did it for one customer, and it has become popular. We are selling them, and there might be some military applications for it,” Organ said. “No one else does it.”
In the near future, new waterjet models from the various manufacturers are expected.
Peake said that HamiltonJet “has a very aggressive development program going on now.” That program includes new waterjets and waterjet controls. “Reducing weight, a more compact footprint and better efficiency” are part of the deal.
MJP has several models on the drawing boards. “They are different designs and dimensions and are lighter,” said Tilton.
And Rolls-Royce has its own hydrodynamic research center in Sweden where, said the company’s Eric Larsen, “we are continuously testing pump technologies for our waterjets.”
