APD Class Ships

1943 Photo of the USS SHLEY APD-14

January 1945 Photo of the USS STRINGHAM APD-6

History of the US NAVY "Four Stackers".     "Four Stacker" type destroyers entered service with the US Navy between 1917 and 1922. The 273 four-stackers were comprised of three nearly indistinguishable classes, Caldwell Class (6 ships), Wickes Class (111 ships) and Clemson Class (156 ships). There was little need for these ships subsequent to WW1, and many of them were laid up. They were good ships for the time, but by the onset of WW2 they were outdated. Better armed and more habitable designs were becoming available. Nevertheless, the desperate shortage of fleet escorts early in WW2 made them valuable. Fifty were transferred to the Royal and Canadian navies prior to the US entering the war, and were immediately put to use. These are what we now call the "Lend Lease" ships.  Four stackers saw front line service with the US Navy immediately on its entry into WW2, but as better ships became available they were relegated to convoy escort, fast transport, and other duties.

    The US and Royal navies altered them in ways too numerous to mention. Originally armed with four 4"/50 guns, many US variants were re-armed with 3" guns and various combinations of light and medium AA armament. Radar was enhanced as the war progressed, and convoy escorts carried all the usual anti-submarine armament; depth charges (K guns, Y guns, roller racks) and hedgehogs. Two of their four torpedo tube banks were often landed to compensate for added weight.

    Among the most interesting 4-stacker conversions were the high speed transports. Equipped with four landing craft and accomodations for 200 marines, these shallow draft vessels were put to good use in the Pacific Island campaign. The most famous 4-stacker of all, the HMS Campbeltown, was altered to resemble a German torpedo boat in order to facilitate its entry into the German held port of St. Nazaire. It should also be noted that few of the 4-stackers actually had 4 stacks by the end of WW2.  Many of them had one or two of their 4 boilers removed to increase range or provide additional accomodations, as in the case of the APDs.  Bridge arrangements also changed from that of the original design, especially on the Royal Navy 4-stackers.  As with corvettes, there was a great deal of variety, and a ship could change substantially during the course of the war.  Consult your references if you are modeling a specific ship! 

    Obsolete prior to WW2, there was no reluctance to modify these ships as the mission required.   A good general reference is Flush Decks and Four Pipes by John D. Alden. With numerous US Navy photos of 4 pipers, it documents the many variations among the 273 ships, especially during the WW2 years. Regrettably, both of these references are out of print. They are available on the secondary market, but at a premium. 

Vital Statistics: Note: These are "as built" specifications and essentially the same for all three 4-stacker classes. Fittings and armament differed greatly during WW2