The Royal Institution of Naval Architects (RINA) is noted for its annual summer naval conferences, not just because of its prestige as a professional body but because of the high standard of discussion. Papers are vetted to exclude the standard salesmen’s product plugging, and the discussion from the audience is always vigorous. The conferences also include subjects outside the narrow confines of pure ship design, broadening the appeal considerably.
This year’s conference, held at Trinity House in London on 14-15 June, lived up to expectations. Geoffrey Fuller, Chairman of the RINA Council, suggested that we should think in terms of a littoral zone extending from the outer edge of the Exclusive Economic Zone (EEZ) to 50 miles inland. He called for new concepts in the design of offshore patrol vessels (OPVs), bearing in mind that there has been no major innovation in ship design for nearly 30 years.
His paper, “Blue Water v. Brown Water,” drew attention to the confusion that exists in defining the littoral zone— some preferring to distinguish between the green-water coastal zone and the brown-water rivers and estuarial waters. That quibble aside, he spoke with the authority of long experience as a naval constructor and shipbuilder, reminding his audience that the sea is to be respected, not plundered.
Commander Michael Ranken, Royal Navy, secretary of the United Kingdom Parliamentary Group, reviewed the implications of the 1982 United Nations Convention on the Law of the Sea (UNCLOS). His examples of the depletion of fish stocks around the world struck a chilling note, reminding us all that protecting offshore assets cannot continue to remain nothing more than a matter of national sovereignty.
Several interesting OPV designs were presented, ranging from monohull vessels such as the Blohm+Voss MEKO 100 and the DCN International New Generation Aviso to air-cushion craft such as the ABS M-10. Admiral Rodholm, formerly of the Royal Danish Navy, provided an update of the Stanflex 300 program and introduced the Stanflex 500 variant. Low cost is one of the most important criteria for OPVs, and the 14 small multirole Stanflex 300 ships are said to have cost 20% less than the same number of conventional craft they have replaced. The appeal of the Stanflex concept is the way in which containerized weapon and sensor fits can be exchanged to suit changing mission requirements.
The ABS team presented the M-10 hovercraft, a third-generation design optimized for the military and paramilitary market. The concept centers around low acquisition cost, affordable operating costs, and good seakeeping, diesel engines rather than gas turbines, and simple but robust structures. The hull is fabricated from single-skin glass-reinforced plastic with a Kevlar superstructure. The prototype M-10 has recently been evaluated by the Royal Swedish Navy for over-ice operations and completed the first winter circumnavigation of the Baltic.
On the technical side, Lockheed Martin Missiles & Space presented a paper on the application of stealth technologies to OPVs. Although the paper was clearly presented and very interesting. I for one was not convinced that the full range of 'bolt-on stealth’ measures are as cheap as claimed. They may be cheaper than the measures adopted for major combatants, but still not cheap enough for the majority of OPV users. Low probability of intercept (LPI) radars to allow OPVs to defeat the commercially available radar warning systems used by drug smugglers, or simple electronic support measures (ESM) systems to detect radio and radar transmissions are needed (and they are affordable). Radar absorbent materials (RAM) and elaborate measures to reduce radar and acoustic signatures seem likely to add considerably to the price of a ship intended to deal with infringements of fishing rights.
The representative of Lockheed’s Canadian subsidiary was unable to present his paper on the design of ESM systems suited to the offshore mission. This was a great pity, as the written paper outlined the requirements for ESMs in the offshore protection environment without promoting any specific piece of equipment.
To remind the naval architects and designers in the audience of the realities of seakeeping, Ken Hope of Australia’s Department of Aerospace & Mechanical Engineering presented a paper on a detailed set of trials of the 42-meter patrol craft HMAS Wamambool. These instrumented trials were carried out in the Bass Strait in August 1992 to study the effects of combined sea and swell on motion levels and frequency spectra. Hope said that the experience proved that full-scale experiments at sea need not be too costly, and are more convincing than computer estimates.
United Kingdom navigation specialist Kelvin Hughes provided information on their integrated bridge system. This comprises the linked color tactical display (CTD), an electronic chart display unit (CDU) displaying Admiralty Raster Chart Service (ARCS) charts, and a P-code global positioning system (GPS). The system is currently being tested at sea in the liner QE2 and HMS Sheffield, winning high praise from the Navy. The U.S. Coast Guard also is evaluating the CTD to meet its requirement for a new standard bridge display.
The French New Generation Aviso has yet to be built, but it is the basis for a recent (unsuccessful) bid to win the contract to supply four corvettes to the South African Navy. The design derives from work done on the new La Fayette-c\ass ‘stealth’ frigates, although the design is smaller and cheaper. The criteria are reduced cost, limited displacement, containerized combat system, ability to operate a 20,000-pound helicopter, accommodation for 100 personnel, and maximum survivability. On an overall length of 86.6 meters and a standard displacement of 1,500 tons, the Aviso carries a medium-caliber gun and a helicopter—10,000-pound class in the hangar or 20,000- pound class on deck. Twin-shaft diesels or a combined diesel and electric (COD- LAD) drive would produce a speed of 24 knots and a range of more than 6,000 nautical miles. The combat system is developed from the SEN1T 8 in the new French carrier Charles de Gaulle.
At the opposite end of the spectrum is the small waterplane area twin hull (SWATH) design. Much has been expected of the SWATH, but to date only the U.S. Navy and Japan's Maritime Self-Defense Force have shown any willingness to invest in the concept. A paper presented jointly by Swath International and Blyth Bridges Marine Consultants set out the arguments in favor of a SWATH solution to the offshore patrol mission. The advantages are superb seakeeping on a compact and comparatively cheap hull, and the exceptional stability enhances helicopter operations.
Against these must be set the vessels’ sensitivity to load and excessive draft. In effect, this means that SWATHs are responsive to any subsequent modification which increases all up weight. Top speed and first cost will be higher than a monohull or catamaran of similar displacement.
The conference looked at a variety of solutions to the problems of offshore protection. Low cost is one common denominator, but by no means the only factor. The dash mission, using small, high-speed interceptors, is valid for countries lucky enough to have their assets concentrated in sheltered waters or operating against drug traffickers and smugglers of contraband (human or otherwise). On the other hand deep sea fisheries can be protected only by Weatherly craft with sufficient endurance to stay at sea for days on end.
Warships can reinforce the efforts of law enforcement agencies, but they are inherently overarmed and expensive for coast guard duties.
The growing sophistication of the smugglers, particularly in the drug trade, is forcing the introduction of more technology, notably ESM systems, passive electro-optical trackers, and even a measure of stealth. One experienced naval officer speaking from the floor reminded the audience that subtlety and deceit have their place in the inventory. In some circumstances, the type of ship should be as non-naval as possible to get close to offenders, in others a powerful, well-armed appearance may contribute to the deterrent effect.
Whether navies share responsibility for offshore protection or delegate it to a paramilitary or civilian force, the mission is not one that can be ignored. At a time of savage budget cutting, it is a valuable means of preserving basic skills of seamanship and command. It also provides a way to spin off technology developed at great expense. As the current dispute between Canada and Spain shows, even prosperous industrialized nations resort to direct action to protect offshore assets.
Antony Preston, a distinguished naval correspondent of long standing, writes the survey column for the Naval Institute’s annual March International Navies Issue.