Montana-class

## Anti-Aircraft

40x- 40mm Bofors

56x- 20mm Oerlikons

## Sensors

The Montana class was designed as an upscaled Iowa-class battleship, designed to meet the build up of large European Battleships. While the Montana was only surpassed by the Michigan class, the Montana was easily on level with many European nations largest battleships. The Montana-class was the finest USN battleship of the second world war, with ships of the class serving in every theater, usually as flag ship.

## Background

After naval intelligence discovered the Yamato-class, plans for a challenger quickly appeared. While the even larger ships of the IJN went unnoticed, they would eventually be countered by the Michigan-class. While it was assumed that the Yamato was armed with 16in guns, the USN naval doctrine at the time led to the design being essentially an elongated Iowa.

However, the early Montana's (the Montana and the Ohio), were equipped with less power then their predessors, only having a top speed of 28 knots. However, over the next iterations of the ships, there would be 2 subclasses, the Iowa Contemporary Maine-class, and the relatively late war addition of the modified Pennsylvania sub-class.

## Montana-class

The Montana-class consisted of a return to the previous mid-1930's USN naval design doctrine. Based heavily on the South Dakota-class and North Carolina-class line of thinking, the Montana saw a massive reduction in power in comparison to the immediate predecessor Iowa-class.

With only 172000 SHP, the Montana-class was 30,000 shp down over the preceding Iowa-class battleship, while being 15000 tonnes heavier then the Iowa-class.

## Maine sub-class

The Maine sub-class was the first ship to fully embrace the 'enlarged Iowa' mentality. The Maine’s had a hull lengthened to 993 ft. Interestingly enough, much of the redesigned internal machinery space was adapted from the Midway class, which was itself based off the original Montana hull. The additional 75ft gave the Maine the same 8.21 length-to-beam ratio as the Iowa-class. Most of this length was contributed to the extension of the engine room, where 4 additional Babcock & Wilcox 2-drum express boilers were added, powering an additional 2 sets of Westinghouse geared steam turbines.

This also increased the normal deployed tonnage by 8,000 tonnes, leading to a mean deployed displacement of 70,000tonnes. The commissioning of the USS Maine in 1946 marked the first USN ship to exceed 70,000 tonnes, and outmatched the Japanese Yamato-class. These engine upgrades gave the Maine sub-class 262,000 shp, 90,000 shp over the original design. These gave the Maine sub-class a speed of 30 knots. While 2 knots faster then the original design, they still lagged behind the Iowa-class at only 30 knots. The first 4 ships main battery was made up of 16in Mark 7/50 guns, identical to those found on the Iowa-class.

While the Montana and Ohio's sloped belt was visible, the Maine sub-class added an addition layer of thin STS steel, giving the bow on profile of the Maine & Louisiana the same 'square' off appearance of the Iowas. This protected the ship from Small arms fire, provided additional fuel space, and improved the general hydrodynamics of the ships.

## Pennsylvania Sub-class

Shortly before the USS Utah was laid down, a noticeable rise of kamikaze attacks prompted a redesign. In particular, the sinking of the USS Pennsylvania (BB-38) by a kamikaze attack not only led to the USS Utah being renamed USS Pennsylvania, but also a revised and heavier AA compliment.
The newly renamed Pennsylvania sub-class was the pinnacle of the modern battleship.

The Pennsylvania was 76 ft longer over the Maine sub-class, leading to the first American warship to be longer than 1000ft, with the Pennsylvania clocking in at 1052ft. The resulting Pennsylvania was also 15,000 tonnes heavier than the Maine, with a total displacement of 85,000 tonnes.
The length was added to allow for the inclusion for another set of turbines. This added an additional 90,000 shp for a total of 352,000 shp. The added length made the resulting superstructure incredibly different from the other ships.
While Maine subclass managed to awkwardly vent the additional 2 boilers through the existing funnels, the Pennsylvania extended the gap between the funnels, (leading to more AA guns being placed in this area), and the funnels themselves being lengthened to allow for more efficent flow of exhaust.

The Pennsylvania sub-class was also the first and only ships to receive the new 16in Mark 9/55 caliber turrets.
The Mark 9 was essentially a modified enlarged version of the Mark 7. With a barrel lengthened an additional 6 feet (55 caliber), the Mark 9 fired the same 16in shell. The largest difference was the inclusion of 3 extra powder bags. While Mark 7s fired using 6 powder bags, the Mark 9 used 9. This gave the Mark 9 much improved accuracy. The Mark 9 used the same loading procedure as the Mark 7, with the difference being an extra rotation of the powder, and an extra round of ramming. This upgrade extended the range of the round an additional 3 miles, for a maximum range of 27 miles.

The rest of the mechanics of the turret was also revised, with the angling mechanism in particular being uprated to be able to handle the extra weight. In total, without the breach the Mark 9 guns weighed 286,000 lbs, 47,000lbs heavier then the Mark 7. The resulting beneath structure had to be reinforced to withstand the additional weight.

Besides that, the rest of Mark 9 gun was identical to the Mark 7, using the same gun carriage and cradle system as the Mark 7.

Due to the increase of Kamikaze attacks, the Pennsylvania was equipped with 12x- 3in/77 AA guns on the superstructure. Due to the increased length, much of the superstructure was revised. An additional 4x- 127mm DP turrets were added, along with the inclusion of 6 extra 40mm Bofors stations, 20 extra 20mm Oerlikons Mk4s, and 20 Oerlikon Mk20s.

While originally designed as a one off, the delays of the USS New Hampshire led to the New Hampshire being laid down as a Pennsylvania sub-class.

## Ships in Class

USS Montana (BB-72)

USS Ohio (BB-73)

USS Maine (BB-74)

USS Louisiana (BB-75)

USS Pennsylvania (BB-76)

USS New Hampshire (BB-77)