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| Corps of Engineers Welcomes Fast Survey Catamarans |
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| Hydrofoil Catamarans Will Speed Ship-Channel Surveys |
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 | | | Boat under way: The new Corps of Engineers high-speed survey boats are 60' hydrofoil-supported catamarans that cruise comfortably at speeds of 20-30 knots. |
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By Peter Marsh
The Portland district of the US Army Corps of Engineers received a pair of new high-speed survey boats last month-the Redlinger and the Elton. These aluminum catamarans are almost 60' long x 24' wide and are the most modern in the nation, thanks to their use of hydrofoils to increase speed and fuel efficiency, and advanced depth-charting equipment. They were built by the Geo Shipyard in New Iberia, Louisiana, one of the few yards with experience in this type, and were shipped from Florida to Vancouver B.C.
They were then driven down the Washington coast and arrived in Astoria last month. Freshwater News was given an exclusive preview of these identical vessels before they begin work on the Columbia River. The crew explained that every month, they make a conditional survey of the 110-mile ship channel, to find out where silt has been deposited and if this is causing shoaling that could possibly cause fully-loaded ships to touch the bottom at low tide.
By the end of this year, when the 20-year project to deepen the channel to 43 feet is complete, the corps will have the responsibility to maintain this depth and ensure that deeper-draft ships can safely navigate the river all the way to the Port of Vancouver. To accurately chart the river bottom, the survey boat makes many passes over a single stretch, covering narrow strips of the bottom around 150' apart, until the depth sound/plotter has built up a complete grid of soundings covering the entire 600' width.
The sophisticated depth sounder/charters can handle a boat speed up to 12 knots and return accurate readings-so conventional monohulls have usually been employed for this work. But that meant a lot of time and fuel was spent going from the base dock to the survey area and returning in the evening. The need for high-speed survey boats had already been recognized, and the corps had previously acquired two fast catamarans to cover the New York harbor area and the Mississippi River
The Corps Embraces High Speed Catamarans
The design of these craft was based on the HYSUCAT concept (hydrofoil supported catamaran) developed in South Africa by Gunter Hoppe, a professor of naval architecture. When the Portland district began planning the purchase of its own high-speed boats, it leased a similar catamaran from Kvichak Marine of Seattle.
The operators were impressed, but asked for some improvements, including more engine room space, better visibility, water jet propulsion, and a more robust mechanism for the sliding strut that carries the transducers. The existing design was revised by Viking Fast Craft Solutions of Staunton, Ill, which holds the rights to the design patent in the US. The construction, mainly of ¼" aluminum plate, complied with the ABS high-speed rule. (Viking is calling its upgrade of the foil system the HYSUCRAFT.)
The result is a vessel with a spacious cabin 17' wide with complete all-round visibility, and an engine room in each hull with walking space on both sides of the MTU (formerly Detroit) Series 60-825hp diesel that turns a Hamilton 403 waterjet. The space aft of each engine is also clean, since the mufflers are mounted outside the hull, inside the swim step.
All the lighting is by 120volt LEDs run off either of the pair of Northern Lights 12 kW gensets. There is a small galley in the starboard hull; the heads are located on the other side. There are no sleeping accommodations, since the boats have the speed to quickly return to base. At full power, noise in the cabin was less than 80 decibels.
A Test Run to the Columbia Bar
The new crew were keen to try the boats out in some rough water before delivering them to Portland, so around noon they left the East Mooring Basin and turned west into a strong breeze and moderate chop. At a speed in excess of 20 knots, there was some vertical movement, but no slamming, thanks to the v-shaped nacelle under the bridgedeck. Once we reached the Clatsop Spit, the motion intensified, but at a reduced speed the motion was tolerable, and one could even walk the length of the cabin without needing handholds.
On the return trip, we were running with the waves, and the same 80% power setting gave us a speed in the high 20s with very little motion. By the time we passed Hammond, the chop was low enough to increase the speed up to 30 knots. At this speed, the hull rises out of the water in planing mode, the front third of the boat lifts clear of the water, and the big water-jet nozzles in the stern are visible above the wake. In smooth water at the east end of Astoria the engines were opened up to the maximum 2300 rpm and we hit 32 knots.
Now it was time to slow down and for all the crew to try out the HamiltonJet blue ARROW control. This is a remarkable system that it is a totally integrated waterjet electronic control package. You grip the control somewhat like a computer mouse and rotate or slide it to indicate the direction you want the boat to go. Magically, this digital device turns the jets' thrust, adjusts the throttles, and moves the buckets so that the boat turns in its length or crabs sideways. The last helmsman had never used it before and was able to bring us gently up to the dock.
Once the boat was moored, I stepped onto the swim step and tried to see the foils, but could barely glimpse the stern trim tabs, which are like horizontal stabilizer fins. The main stainless steel foil that runs from one keel to the other amidships is only visible when the boat is hauled out. If you spend enough time on the river this summer, you are quite likely to see one of these remarkable craft: either the Redlinger (based upstream of the St Johns bridge) or the Elton, (based in Astoria).
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