Tennessee Class Cruiser - Modifications

Modifications

Before North Carolina and Montana were laid down, the Bureau of Construction and Repair (C&R) made some minor design changes in light of experience gained from the Russo-Japanese War. Their main traverse bulkheads remained unpierced below the armored deck and some armor was rearranged. Armor on the barbettes was increased 1 inch (25 mm) on exposed surfaces. Deck armor over the magazines was thickened from 40 pounds (18 kg) to 60 pounds (27 kg) over the magazines; to make up for this weight, side armor abeam was reduced slightly. The magazines were rearranged to allow 20 percent additional 10-inch and 6-inch ammunition without sacrificing coal capacity. Rearranging the berth and gun decks amidships increased coal capacity by 200 tons. Coal bunkers were also modified to allow trimming directly from the upper bunkers to the fire rooms, which was considered potentially advantageous in battle. Throughout this review process, the Bureau sought to save weight whenever possible. For example, cellulose was omitted as water-excluding material as its utility after being packed a number a years had come into question.

In service, the Tennessees went through less refitting than the Pennsylvanias, as many features retrofitted to the latter, such as automatic ammunition hoist structures and longitudinal turret bulkheads, had already been built into the former from the outset. Their power plants were standardized, with Babcock & Wilcox boilers instead of the less reliable Niclausse that had to be removed from two of the Pennsylvanias. Also, since the Tennessees were commissioned up to three years after the first units of the Pennsylvania class, they reached obsolescence earlier in their careers.

Built originally with pole masts fore and aft, these ships were fitted with lattice masts forward and modernizing the bridges in 1912. In early 1917, Washington (by then renamed USS Seattle) was fitted with a seaplane catapult and one other Tennessee-class cruiser, probably Montana, was scheduled to receive one. While the plane was seen as a potential aid in reconnaissance, the catapult precluded use of the aft main guns. This program was cancelled and the catapult removed before the United States entered World War I. During the war, the 6-inch and 3-inch armament was removed and the corresponding ports sealed. This was done to provide guns for arming merchant ships and auxiliaries and to improve watertightness under North Atlantic conditions.