In September 1992, the Naval Sea Systems Command issued the Camouflage Manual for Surface Ship Concealment (now declassified) "To furnish the fleet and force commanders with information on the effectiveness and suitability of various concealment measures and with guidance in the selection of paints and painting schemes for reducing the probability a ship will be initially visually detected and correctly identified." The manual focused solely on a visual threat, reaffirmed the use of haze gray, and ushered in the now familiar camouflage hull numbering scheme, much to the chagrin of some commanding officers who prefenced the sharp black and white numerals-and occasionally still use them.
Today's more complex threat, however, covers a much broader range of the electromagnetic spectrum. As "Forward . . . From the Sea" tells us, our ships will operate primarily in the littorals. Antiship cruise missiles have replaced torpedoes as the major antiship threat and radar is unquestionably the primary surveillance threat. To maximize the survivability of our ships, a balanced-observable approach that reflects both the change in threat and the change in operating scenario is required. This balanced-observable approach will emphasize radar cross-section (RCS) and infrared (IR)-in that order-over the visual band. Recent studies and common sense tell us that there is a tradeoff between visual and IR signatures. As the ship's paint becomes lighter it absorbs less sunlight and does not heat up as much, resulting in lower IR signature. Indeed, the USS La Salle (AGF-3) was painted white while operating in the Persian Gulf to reduce heat buildup. Naval Research Laboratory signature measurements of white Coast Guard ships verify that this type of thermal control translates into IR signature reduction.
The Integrated Ship Signature Study conducted for the Surface Combatant for the 21st Century (SC-21) showed that signature reduction will be effective in countering both the surveillance threat by reducing the RCS-and the antiship cruise missile threat by reducing both radar cross section and infrared signature. Against cruise missiles, lower ship signature increased survivability by improving decoy effectiveness.
NavSea and the Naval Research Laboratory already have taken the first small step in the process of balancing IR and visual signature. Working with the Australian Ministry of Defence, the Laboratory developed a low solar absorbance (LSA) Paint that retains the haze gray appearance, but is very reflective in the near infrared, where half the sun's energy is incident.
In January 1995, NavSea initiated an aggressive program to evaluate this paint for fleet use. The USS Dextrous (MCM-13) was painted LSA haze gray and underwent IR radiometric testing in September 1995. The Laboratory used a low-flying helicopter to measure signatures. It circled the Dextrous and other Avenger (MCM-l)-class minesweepers maintaining the same course and speed. The second ship acted as a control to establish a baseline from which to calculate paint effectiveness. Data analysis established that sunlit-side IR signature was significantly reduced in the IR threat bands.
NavSea has nearly completed formal LSA paint qualification. This comprehensive effort has included: reformulation of the paint by a commercial vendor to satisfy fully current color and gloss requirements, accelerated aging, and modification of the specification for commercial production. Manufacturing costs are estimated to increase a negligible two cents per gallon. (Standard haze gray paint costs about $30 per gallon.) Pending the completion of year-long weathering trials, NavSea will authorize fleet use of the new paint on a case-by-case basis.
The Naval Sea Systems Command and the Naval Research Laboratory are pursuing other applications for LSA paints. A standard light gray paint has been developed for special topside equipment, such as the Phalanx Close-In-Weapon System and ammunition lockers, which presently are painted white to lower internal air temperatures. Following successful electronics impact temperature testing, both weapon system radomes on the USS Donald Cook (DDG-75) were recoated with light gray paint this year. In a related effort, a nonskid deck paint is being developed strictly for heat reduction.
Current paints, even with the introduction of LSA paint, heavily bias threat assumptions toward the visual band while sacrificing performance in the IR portion of the spectrum. We must decide on the next-generation paint scheme, based on current and future threats, emphasizing the littoral environment, to incorporate a balanced observable solution. Reintroducing effective camouflage and countershading can help keep visual detectability low as IR signature concerns raise the average visual reflectance, e.g., lighter shades of gray. Several navies, including those of Australia and Denmark, have recognized this and already are reevaluating their old color schemes. While focus continues on the SC-21, existing surface vessels could easily be repainted, improving survivability for the entire fleet.