// Active Rating · CM · Seabees (NCF)

CONSTRUCTION MECHANIC (CM)

The Seabee heavy-equipment and vehicle mechanic — every Seabee dozer, dump truck, and crane stays running because of a CM.

Rating Badge

Rating Code

Community

Seabees (NCF)

Paygrade Range

E-1 to E-9

ASVAB Minimum

AR+MK+AS=162

A-School

Naval Construction Training Center, Gulfport, MS · ~13 weeks

Clearance

Standard

Obligation

4 years

OVERVIEW

Construction Mechanic (CM) is the heavy-equipment and vehicle-maintenance rating in the U.S. Navy's Naval Construction Force. CMs maintain the dozers, graders, scrapers, dump trucks, cranes, asphalt pavers, and tactical vehicles operated by the Naval Mobile Construction Battalions. CMs are the wrench-turners that keep the Seabee Civil Engineer Support Equipment (CESE) fleet mission-capable in garrison and on contingency deployments.

CMs work alongside Equipment Operators (EO) — EOs run the equipment, CMs fix it.

The Seabees — the Naval Construction Force (NCF) — are the U.S. Navy's expeditionary engineers, building airfields, camps, bridges, roads, and piers in austere locations worldwide. Seabees deploy with Naval Mobile Construction Battalions (NMCBs), Underwater Construction Teams (UCTs), and Naval Construction Regiments. Their motto, "Construimus, Batuimus" — "We build, we fight" — captures their dual role.

A-school for the rating runs ~13 weeks at Naval Construction Training Center, Gulfport, MS, where Sailors complete the technical foundation needed to report to their first fleet command. Entry requires the ASVAB line score AR+MK+AS=162 and an enlistment obligation of 4–6 years. CMs advance through the standard enlisted paygrade structure (E-1 through E-9), competing in the Navy-Wide Advancement Examination (NWAE) at E-4 through E-6 and via the Selection Board at E-7 through E-9. Senior CMs typically serve as Leading Petty Officer (LPO), Work Center Supervisor, Leading Chief Petty Officer (LCPO), or Command Master Chief (CMC), and may pursue Limited Duty Officer (LDO), Chief Warrant Officer (CWO), or commissioning programs such as STA-21, MECP, or OCS.

Across the active force, CM Sailors are essential to the Navy's mission readiness, and the rating remains an in-demand career field with strong reenlistment bonuses (SRB), advancement opportunities, and pathways into Navy Reserve, civilian DoD, and industry careers after service.

WHAT CMs DO

CMs perform organizational and intermediate-level maintenance on all Seabee Civil Engineer Support Equipment (CESE): dozers, motor graders, front-end loaders, dump trucks, cranes, hydraulic excavators, asphalt pavers, concrete mixers, generators, and air compressors. CMs also maintain the M-series tactical wheeled vehicles (HMMWV, MTVR, LVSR) that NMCBs operate on contingency deployments. CMs perform engine overhauls, hydraulic-system repairs, transmission and final-drive work, and welding/cutting on chassis and frames.

RESPONSIBILITIES

CMs perform organizational and intermediate-level maintenance on all Seabee Civil Engineer Support Equipment (CESE): dozers, motor graders, front-end loaders, dump trucks, cranes, hydraulic excavators, asphalt pavers, concrete mixers, generators, and air compressors. CMs also maintain the M-series tactical wheeled vehicles (HMMWV, MTVR, LVSR) that NMCBs operate on contingency deployments. CMs perform engine overhauls, hydraulic-system repairs, transmission and final-drive work, and welding/cutting on chassis and frames.
Stand watches and qualify on the rating's Personnel Qualification Standards (PQS), maintain training jackets, and mentor junior CMs as required by the chain of command.
Lead the CM work center as Leading Petty Officer or Work Center Supervisor — managing maintenance documentation in 3M/MFOM, parts ordering, and personnel qualifications.
Support general military training (GMT), damage control, force protection, and watch-bill assignments common to every Sailor regardless of rating.

HISTORY

Construction Mechanic was established as a specialty in the original 1942 Seabee construction battalions and consolidated under its modern name in the post-WWII rating reorganization. The rating has tracked the evolution of construction equipment from gas-powered to high-horsepower diesel hydraulics, from mechanical fuel injection to modern electronic engine controls.

Today CMs maintain a CESE fleet that includes Caterpillar D7/D9 dozers, John Deere graders, Komatsu loaders, Tier 4 emissions-controlled diesels, and the M-series tactical wheeled vehicles that move Seabee battalions worldwide.

The Naval Construction Force was established on 5 March 1942 by RADM Ben Moreell of the Civil Engineer Corps to provide militarized construction units for World War II — replacing civilian contractors who, under the laws of war, could not resist enemy attack. The Seabees built bases, airstrips, and pontoon causeways across the Pacific and Europe and have deployed in every conflict since.

Today the Construction Mechanic (CM) rating is overseen by the Enlisted Community Management (ECM) office at My Navy HR and the Center for Personal and Professional Development. Modern CMs benefit from the Sailor 2025 personnel-system reforms, the Ready Relevant Learning (RRL) training continuum, and credentialing through the Navy COOL program — turning rating qualifications into industry-recognized certifications and licenses.

The rating's structure, training pipeline, and operational employment continue to evolve alongside the Navy's transition to Distributed Maritime Operations (DMO), Project Overmatch, and the Force Design 2045 fleet architecture, ensuring CMs remain central to the warfighting mission.

TRAINING PIPELINE

1. Recruit Training (Boot Camp)~10 weeks
Naval Station Great Lakes, IL
Initial entry training for all U.S. Navy enlisted Sailors at the Navy's only boot camp.
2. Construction Mechanic A-School~13 weeks
Naval Construction Training Center, Gulfport, MS
Initial rating-skills training for CM accessions.
3. Fleet / Operational TourFirst sea or operational tour
Naval Mobile Construction Battalions (NMCBs)
On-the-job training and qualifications in the CM rating with a fleet unit.

TYPICAL CAREER PATH

E-1/E-3
Apprentice CM
A-school at Gulfport; first tour in an NMCB Equipment Maintenance company.
E-4/E-6
Petty Officer CM
Qualify as equipment-mechanic crew leader, shop foreman, and CESE inspector.
E-7+
Chief Construction Mechanic
Equipment Maintenance Company Chief, NMCB Operations LCPO, or instructor at NCTC Gulfport.

TYPICAL PLATFORMS & UNITS

Naval Mobile Construction Battalions (NMCBs)
Naval Construction Group staffs
Underwater Construction Teams
Expeditionary contingency construction worldwide

EXAMPLE NECs

CM-5851 Diesel Engine Overhaul Supervisor

How to address

As an enlisted Sailor by paygrade and last name (e.g. "Petty Officer Smith" for E-4–E-6, "Chief Smith" for E-7+). The rating abbreviation "CM" is appended to the paygrade in writing — e.g., CM1 Smith for CM Petty Officer First Class.

Prerequisites

U.S. citizenship and minimum ASVAB AR+MK+AS=162
High school diploma or equivalent
Pass the Navy physical and medical screening

Common assignments

Naval Mobile Construction Battalions (NMCBs)
Naval Construction Group staffs
Underwater Construction Teams
Expeditionary contingency construction worldwide

RELATED RATINGS

RELATED BASES

Navy Base · CA
Naval Base Ventura County

FREQUENTLY ASKED QUESTIONS

CMs maintain the heavy construction equipment and tactical vehicles operated by the Seabee battalions: dozers, graders, dump trucks, cranes, hydraulic excavators, asphalt pavers, and the HMMWV/MTVR fleet.

Construction Mechanic A-school is at the Naval Construction Training Center, Naval Construction Battalion Center Gulfport, MS.

Construction Mechanics (CM) maintain and repair Seabee heavy equipment. Equipment Operators (EO) operate that equipment. The two ratings work side-by-side on every Seabee project.

SOURCES

Last updated 2026-05-02

All Seabees (NCF) Ratings All Navy Ratings