Because of delays in the modernization of San Diego's harbor defenses, the Army installed a battery of four mobile, 155mm guns 300 yards north of the new Point Loma lighthouse before World War II. Battery Point Loma covered the water areas to the west and northwest of San Diego. The guns arrived at Fort Rosecrans in 1939.
Overall, dimensions are twenty-one feet, eight inches by fifteen feet, eight inches. Constructed during World War II, this concrete and steel fire control station was most important in Harbor Defenses of San Diego in that the battery commander of 16-inch-gun Battery Ashburn operated from the top level (BC3) directing the fire of his guns.
Soldiers manned steel-reinforced concrete bunkers containing Base End Stations, and scanned the horizon for enemy vessels. Should the enemy be sighted, they relayed their information to a Battery Commander, who precisely calculated the enemy’s position, then issued orders to various gun batteries that guarded the approach to San Diego.