APPLICATIONS OF SWATH TECHNOLOGY
Applications of SWATH technology are expanding at an exponentially growing rate. The SWATH concept was originally patented at the turn of the century. However, it wasn't until after the U. S. Navy conducted extensive research in the late 1960's that sufficient technical data existed to allow the actual design and construction of a SWATH vessel in the U. S. In fact, the first SWATH ever built in the United States was the SSP Kaimalino, which was a prototype vessel constructed in 1973 by the U.S. Navy. The Kaimalino operated very successfully as a U.S. Navy range support vessel up until very recently.
Unfortunately for the technology, the Navy allowed the government engineers who were conducting the SWATH research to obtain patents for rather basic features of the design. Provisions were made so that the U.S. Navy would have license-free use of the technology; but any commercial concern would have to buy the rights from these engineers.
These patents effectively created a seventeen year hiatus for the technology in the U.S. (seventeen years is the number of years of protection granted by a U.S. patent.) Following the construction of the SSP Kaimalino, the engineers were able to produce four SWATHs: Betsy, Halcyon, Chubasco and the Frederick Creed. (Figure 6.) Each of these vessels are less than 80 feet long and service as yachts, work boats and an America's Cup sailboat race tender.
In the meanwhile, before a second SWATH was built in the U.S., the Japanese through the Mitsui Corporation, working outside the U.S., designed and built seven SWATHs: 41' Marine Ace, 118' Seagull, 89' Kotozaki, 197' Kaiyo, a sister vessel to the Seagull and two 73' yachts.
After building the SSP Kaimalino, almost ten years lapsed before the U.S. Navy began building additional SWATHs. One of the reasons for the delay was typical government bureaucracy and reluctance to change. Another reason was the perception by some of the military planners that the SWATH hull was more expensive to build. It wasn't until commercial marine fabricators had produced dozens of semi-submersible drilling rigs, which use very similar construction techniques used to construct a SWATH, that the construction costs were proven to be comparable to monohull construction costs.
Ironically enough, at the time SWATH technology was being developed, the Navy embarked on a building program for a fleet of large monohull ships that were to go into the North Atlantic to tow underwater listening devices in search of potentially unfriendly submarines. The notorious North Atlantic Sea is one of the roughest bodies of water on Earth. Twenty foot seas and larger are common sea states during the North Atlantic winter. Today, because of their inability to operate consistently in the rough waters, those monohull ships are being replaced by 232 foot U.S. Navy SWATHs.
In the late 1980's, the patents held by the U.S. Navy engineers expired and today, we are seeing a growth of new commercial SWATHs under construction and operation. Among the SWATH vessels presently in operation as commercial vessels are the Navatek I, a luxury dinner cruiser based in Hawaii, and the Radisson Diamond, an upscale 354 passenger cruise ship.