Moving all the way forward on the OLYMPIA's Spar Deck, and passing under the navigation bridge, the visitor will overlook the fo’csle with its two large anchors, the equally-large bower anchor, associated cranes, and, of course, the forward eight inch gun turret. Immediately to the visitor’s port side, on the vessel’s centerline, is a large armored steel cylinder. This is the conning tower, the abode of Captain Charles Gridley during the Battle of Manila Bay. Squeezing into the small curved passage at the rear of the conning tower, only 21 inches wide, and low enough that the visitor must duck his head, the visitor will soon find himself in the cramped interior of the conning tower.
 

The conning tower is oval-shaped, with the long, seven feet, ten inch dimension running perpendicular to the vessel’s centerline and the shorter five feet dimension running parallel to the centerline. The bulkhead of the conning tower is double-walled, with the outer wall being five inches of armor and the inner wall being one inch. The overall bulkhead is fifteen inches thick. The height to the center of the curved, armored roof of the structure, is six feet. Just below the curved roof of the structure is a small slit, about an inch high. This slit, extending about two-thirds of the way around the conning tower gave Gridley his view of the battle. From within the confines of this stifling location, Gridley could have full control of the vessel. The conning tower contains the main steering battle station (unused in the battle, as Dewey retained steering control in the pilot house), two engine order telegraphs, and voice tubes that communicated with the critical areas of the vessel, such as the engine rooms, steering, etc. Also a fire alarm could be sounded from this location.