The term “CB” is a widely recognized shorthand for the construction force of the U.S. Navy. These specialized personnel, formally known as Naval Construction Force members, are commonly referred to by the phonetic pronunciation of their abbreviation: Seabees. This article will explain their core mission, trace their historical origins, detail their organizational structure, and explore the various construction trades they perform.
What the “CB” Stands For and Their Core Function
The initials “CB” stand for Construction Battalion, the formal designation of the U.S. Navy units specializing in military engineering and construction. The nickname “Seabee” is a homophone of these initials, becoming the force’s universally adopted identity. Their core function is encapsulated in the Latin motto, Construimus, Batuimus, which translates to “We Build, We Fight.”
Seabees are the Navy’s primary expeditionary engineering and construction branch. They are tasked with creating and maintaining infrastructure in austere and often hostile environments. This mission requires them to be fully trained combatants capable of defending their projects, equipment, and personnel. They are responsible for everything from building airfields, roads, and piers to establishing complete forward operating bases.
The dual nature of their work—construction and combat—sets them apart from civilian contractors and traditional military engineers. They deploy rapidly to support naval and Marine Corps operations, ensuring that necessary logistics and infrastructure are in place. This capability to build while providing their own security ensures operational success in contested areas.
Origins and Legacy of the Seabees
The Naval Construction Battalions were officially authorized on March 5, 1942, shortly after the United States entered World War II. The need for a militarized construction force became apparent when civilian contractors working overseas were unable to defend themselves. Under international law, these contractors faced execution if they resisted attack.
Rear Admiral Ben Moreell, Chief of the Navy’s Bureau of Yards and Docks, recognized the operational gap and advocated for construction workers who were also trained to fight. The initial recruits were skilled tradesmen, many with prior civilian experience. Standards for age were initially waived to recruit this specialized workforce. By the end of the war, more than 325,000 Seabees had served, building over 400 bases across the globe.
The force quickly developed a legacy for speed and ingenuity, often working under fire to transform remote islands and beaches into operational bases, airstrips, and hospitals. Notable projects include the construction of the Amundsen-Scott South Pole Station in Antarctica and Naval Air Station Cubi Point in the Philippines, which involved moving half a mountain. Their ability to “Can Do” difficult tasks cemented their reputation as a crucial part of the U.S. military’s global reach.
Seabee Organizational Structure
The Seabees are organized under the Naval Construction Force (NCF), which provides the Navy and Marine Corps with a mobile construction capability. The NCF is structured to support expeditionary operations and includes both active duty and reserve components. The primary operational unit is the Naval Mobile Construction Battalion (NMCB), often pronounced “Seabee Battalion.”
Each NMCB is a self-sufficient unit designed for rapid deployment, staffed with personnel across all necessary construction and support ratings. These battalions rotate between homeport periods for training and equipment maintenance, and deployment cycles worldwide. The NCF also includes Naval Construction Regiments (NCRs) and Naval Construction Groups (NCGs), which provide command and control over multiple battalions.
The Seabee Reserves play a substantial role, augmenting the active duty force during mobilizations and deployments. Reserve units, such as reserve NMCBs, conduct training and readiness drills to ensure seamless integration with the active component when called upon. This structure ensures the NCF maintains a scalable force, capable of responding to both peacetime and wartime requirements.
Key Seabee Ratings and Specializations
Seabees hold specific Naval “ratings,” which correspond directly to specialized civilian trades. These ratings ensure that each battalion is staffed with the complete range of construction skills needed for any project. The six primary construction ratings are detailed below.
Builder (BU)
The Builder rating encompasses general construction trades and represents the largest segment of the Seabee force. These personnel are skilled in carpentry, framing, roofing, and interior and exterior finishing work. Builders erect, repair, and maintain wood, steel, and concrete structures, including barracks and bridges. Their duties include installing drywall, laying floor and ceiling tile, and interpreting architectural blueprints. Builders also perform masonry work, mix and finish concrete, and estimate material, labor, and equipment requirements.
Construction Electrician (CE)
Construction Electricians install, maintain, and repair electrical power and lighting systems required for forward operating bases. This involves working with high-voltage and low-voltage electrical distribution networks, including overhead and underground systems. CEs splice cables, string wires, and install transformers and distribution panels. They also maintain and repair electrical components such as motors, switches, and solenoids, and operate electrical generators. Construction Electricians ensure all facilities have reliable power and lighting, and they install and manage fire alarm, public address, and telephone systems.
Equipment Operator (EO)
Equipment Operators are heavy machinery specialists who manage earthmoving and material handling aspects of construction projects. They operate a diverse fleet of equipment, including bulldozers, cranes, graders, scrapers, and excavators. EOs are proficient in site preparation, including excavation, grading, and roadway construction. They also work as members of crane crews, rigging cable assemblies and changing attachments for lifting and pile-driving operations. Equipment Operators perform minor maintenance on their machinery to ensure operational readiness in remote locations.
Steelworker (SW)
Steelworkers specialize in metal fabrication, structural steel erection, and welding. They are responsible for assembling and reinforcing heavy structures, such as steel bridges, storage tanks, and pre-engineered buildings. Steelworkers perform arc welding and gas welding on all types of metal, including reinforcing steel in concrete structures. Their duties include fabricating metal components, such as trusses, gates, and gratings, from raw stock and plans. They also read and interpret blueprints to ensure accurate fabrication and assembly.
Utilitiesman (UT)
Utilitiesmen specialize in the installation, operation, and maintenance of all utilities within a constructed facility. They are skilled in plumbing and pipe-fitting, managing systems for water and wastewater treatment, and purifying water for consumption. They also handle the installation and repair of heating, ventilation, and air conditioning (HVAC) systems. Utilitiesmen ensure sanitary conditions and environmental compliance by operating and maintaining wastewater treatment plants.
Construction Mechanic (CM)
Construction Mechanics are heavy equipment maintenance and repair specialists for the entire battalion. They ensure the operational readiness of the NCF’s fleet of civil engineering and construction equipment. CMs diagnose and troubleshoot mechanical and electrical failures in diesel and gasoline engines. Their work involves maintaining and repairing frames, bodies, and chassis, along with adjusting steering, ignition, fuel, and hydraulic systems. Construction Mechanics also manage shop functions, including maintenance scheduling and spare parts inventory control.
Operational Scope and Deployment
Seabees deploy globally, often supporting naval and Marine Corps units by establishing and sustaining expeditionary logistics and forward operating bases. Their ability to rapidly deploy with equipment and operate autonomously allows them to execute projects in remote regions. They are armed builders, prepared to transition from construction to self-defense when necessary.
The operational scope extends beyond combat support to include humanitarian aid and disaster relief missions worldwide. Following natural disasters, Seabees are often among the first responders, using their construction skills to clear debris, repair infrastructure, and restore essential services. They conduct engineering civic action projects in developing nations, such as building schools, clinics, and clean water systems, which promote regional stability.
This dual capability—supporting combat operations by building tactical infrastructure and promoting stability through civil engineering projects—makes the Seabees an adaptable force. Their deployments ensure that the U.S. Navy and its partners have the necessary physical foundation to project power and respond to global contingencies. The NCF often remains in theaters of operation after major combat has subsided to rebuild and train local forces.
Joining the Seabees: Training and Requirements
The pathway to becoming a Seabee begins with meeting the general military requirements for enlistment, including age, physical fitness, and minimum scores on the Armed Services Vocational Aptitude Battery (ASVAB). Prospective Seabees attend the standard eight-week Recruit Training Command (Boot Camp) at Great Lakes, Illinois, for initial military indoctrination.
Following boot camp, new recruits attend a specialized technical school known as “A-School,” where they learn the fundamentals of their selected rating. Most Seabee A-Schools are located at the Center for Seabees and Facilities Engineering (CSFE) in Gulfport, Mississippi. The duration of A-School varies by rating, but it provides the foundational knowledge and practical skills for their construction trade.
After A-School, Sailors report to their first operational unit, typically a Naval Mobile Construction Battalion. Here, they receive additional military training, often referred to as Expeditionary Combat Skills (ECS) training. This training focuses on field fortifications, small unit tactics, convoy security, and defensive operations. This ensures they are prepared to operate and defend their construction projects in any environment.