No-Maintenance Solution for the US Navy
For more than one hundred years U.S. Navy sailors have been defending the nation from under water within the completely enclosed and close-quartered submarine vessel environment, often for months at a time. As a result of their dedicated service under the ocean surface, submariners are usually eager to return to port where they can reunite with the expansive outside environment to stretch, refresh and re-energize.
When submarines come to port to give the sailors and officers a much deserved respite, the dock that hosts the submarine must be properly equipped to handle the vessel, which unlike surface ships, sits very low in the water. To prevent damage to the vessel and port structures as the submarine is berthed and moored to the pier, special floating structures separate the underwater vessel from the pier. These steel and wood barrier structures are known as deep draft camels.
Camels protect various parts of the submarine from being damaged including the hull, diving planes, screws, fairings, special skin treatments and other appurtenances. As the submarine moves during berthing and mooring, the camels compress and deflect to absorb its energy.
The Navy has been using several different types of submarine camels. Many factors, including environmental conditions, pier and fender system designs, and operational requirements, led to the use of the different types of camels. The variety of camels, however, is problematic from a procurement standpoint, but more importantly the steel and wood construction, which is almost completely submerged in seawater, is subject to corrosion and degradation.
As a result of the variety of submarine camels, the Navy set out to standardize them to increase efficiency, reduce inventory and potentially reduce life-cycle costs. The Naval Facilities Engineering Command (NAVFAC), Atlantic was tasked with studying the option of going to a universal camel design that could handle all of the Navy’s submarine classes. According to Frank Cole, Special Assistant for Waterfront and Harbors with NAVFAC Atlantic, the common design would be a universal solution. “We designed the camels so they are one-size fits all. For instance, they were designed for all classes of submarines and intended to be used at all ports in the world.”
The new camels were also designed to eliminate the problem of corrosion and therefore minimize maintenance. A fiber-reinforced plastic (FRP) composite material was chosen for the new design because it offered all of the properties and characteristics to build a resilient and long-lasting camel structure. “The corrosion resistance of FRP composite material is the perfect solution for the constant seawater and salt conditions [to which these camels are subjected],” said Scott Reeve, president of Composite Advantage, the contractor selected to design and build the first set of the new composite camels.
To test the technology and design, a set of prototyped composite camels was deployed at the Navy’s submarine base in New London, Connecticut. “The Naval Facilities Engineering Service Center did a one-time demonstration project just over 10 years ago,” said Cole. “In 2000, we put a set of composite camels in the water as part of the research and development effort.”
The demonstration project showed that the new camels lived up to their low-maintenance expectations. “For now, we do periodic inspection and maintenance as needed, but very little has been required so far,” said Cole. “For example, in late 2008 we pulled the [prototype] camels out of the water, which had been deployed since 2000. They were in great shape.”
Cole noted that the Navy transitioned the prototype design into a more universal design for use with all classes of Navy submarines. “We used that technology to come up with a more generic product.”
Although the initial cost of the composite camels is higher than traditional camels, the life-cycle costs are expected to be lower due to the reduced maintenance needs. As noted above, after 10 years demonstrating the prototype camels during which they required no maintenance, the camels were removed from the water for a more complete inspection. Unlike their traditional steel counterparts, no corrosion or degradation was found. There was only some minor algae buildup on the exterior surface. The outstanding resilience to the harsh underwater environment can be attributed to classic polymer-based materials.
“There are composite chemical tanks that have almost 50 years of life without degradation,” said Reeve. “They don’t need maintenance from exposure to water and chemicals. Ideally we’d like to make sure that the camels last the Navy 25 years, but they should last longer. Based on what we have seen from the prototype and other uses of composites, the camels should go longer than 25 years.”
“For the new composite camels, we plan a once-annual visual inspection to ensure the camel is floating correctly,” Reeve added. “Every five years, the divers should go in and inspect the camel by looking around at the part under the water. There is no scheduled or planned maintenance, and no reason to pull them out.”
Today, you can find Composite Advantage submarine camels at Subase New London, Norfolk Naval Station, Naval Base Kitsap and Submarine Base Kings Bay. Variations on the Universal Camels include options for stand-off distances, open ocean environments, high tidal conditions and hurricane hardening.
US Navy
Naval Submarine Base New London
Norfolk Naval Station
Naval Base Kitsap
Submarine Base Kings Bay
36 ft
18 ft
17 ft
70,000 lb
35,000 lb
Corrosion resistant to sea water and chemicals
Long lasting
Rub strips for smooth interface with pier pilings
Universal design
Reduces life cycle costs
No maintenance requirements
