CBU 421

• Establishment: CBU 421, or Construction Battalion Unit 421, was established during World War II as part of the United States Navy’s Seabees (“CB” stands for Construction Battalion). • World War II Service: The unit was primarily active in the Pacific Theater, supporting major amphibious operations by constructing airfields, roads, and bases under combat conditions. • Island Hopping Campaign: CBU 421 played a crucial role in the island-hopping strategy by building infrastructure on newly captured islands, enabling rapid follow-on operations. • Engineering Innovations: The unit was known for improvising construction techniques using limited resources, often repurposing damaged enemy equipment and salvaged materials. • Combat Experience: Members of CBU 421 frequently came under enemy fire while constructing forward bases, and several were awarded commendations for bravery. • Notable Projects: One of their celebrated achievements was the rapid construction of an airstrip on Iwo Jima, which became vital for emergency landings of damaged B-29 bombers. • Postwar Activities: After WWII, CBU 421 assisted in occupation duties, including rebuilding infrastructure and clearing debris in Japan and the Philippines. • Unit Legacy: The traditions and lessons learned by CBU 421 influenced postwar Navy construction doctrine and the modern Seabees’ “Can Do” spirit. • Decorations: The unit received multiple unit citations for its contributions, including the Navy Unit Commendation and campaign medals. • Veteran Stories: Former members have recounted stories of camaraderie, ingenuity under fire, and the importance of their work in helping turn the tide of the Pacific War.