Author: *Vollketten (with some suggestions by Captain Nemo) The Okinawa Sherman Of all the tanks in WW2 few could rivalry the sheer numbers produced, the number of front served in or the vast number of modifications carried out. Many of these modifications were on a very small scale so are not necessarily distinct or common enough to warrant a special vehicle. There is of course the battle for Okinawa for which modifications were extensive in both numbers and appearance. Most people will have seen Shermans covered with sandbags in books or footage of the war. To cover an entire Sherman it was found to take about 170 full sandbags to cover an M4 adequately although up to 200 were used on occasion. Initially secured with wire mesh and later with welded steel brackets and was often done on a wide scale. The 14th Armored Division in Europe “systematically sandbagged their tanks prior to entering combat”. Estimate a sandbag at approximately 10kg and this adds a considerable 1.7 to 2 tonnes to the vehicle. How effective were they? Well on the 28th July 1944 3rd Armored Group tested the effectiveness of this armour on an M4 using a Panzerfaust. As a result of the test a truck drove back to the landing beach to get more sand. (11) In the pacific sandbags were sometimes placed on the rear deck to protect against antitank mines or satchel charges thrown onto the rear deck but overall the use of sandbags was found to improve the overall effectiveness of the vehicle armour against shaped charge warhead based weapons such as the panzerfaust but not make any noticeable difference against anti-tank guns. Concrete was widely employed in some units often on the glacis and also in the Pacific as a layer against the sides of the tank cast against a layer of planks on the side of the tank. This was done by the Marine Corps where the planks left a void about 100mm wide against the sides which was then filled in as both a measure to improve the armour against the Japanese antitank guns but also to prevent the sticking of magnetic mines to the sides by Japanese infantry. Other measures to protect against these mines included wire cages over the hatches and the US 750th Tank Battalion went so far as to put up to 150mm of concrete on their M4 tanks and even nails welded on. Spare track sections were widely used in all theatres of the war by crews and provided some additional protection against kinetic energy weapons and a slightly greater stand-off distance for HEAT type weapons. In the Pacific the addition of steel track sections welded to the turret and sides was found to “reduce the effectiveness of the Japanese 47mm high velocity antitank guns”. These guns were a very real danger to the M4 where for example we have an account from the 193rd Tank Battalion in April 1945 where a single Japanese 47mm antitank gun knocked out 4 of the battalions medium tanks in a single day. (9) This is ‘Agony’ still with its wading system knocked out and repeatedly penetrated by Japanese 47mm antitank rounds. Side skirts for the M4 were at least trialled formally back in the US in 1943 copying the side skirts from the T14 Assault Tank and found to be of “dubious value in detonating APHE type shells, but that they will reduce track damage due to explosions of HE shells where those shells detonate against the skirting plates”. Side skirts were also used on Okinawa either as fabricated steel panels like this: Or as wooden planks fastened to welded-on steel frames. The goal was not so much protection against anti-tank rounds but as a measure to counter the insane bravery of the Japanese soldiers who could throw or place satchel charges or Type 99 magnetic mines against the hull. Japanese Model 99 Magnetic Mine Davy Jones was knocked out and burned after being hit by 3 Japanese 77mm shells. The crew survived that incident. This vehicle also has two panels on either side of the glacis as well: ‘Cloudhopper’ was knocked out by a 47mm AT round through the side. (8) “Track blocks had been welded on turrets and front slope plates in the staging area. However, during the operation it became necessary to weld track on all sponsons.“ (6) “The planking on the sides is considered to have been effective against shaped-charges thrown at several tank so equipped….the planking was splintered or blown off entirely, but the armor plate was not affected” (7) “No case is recorded in which the wooden skirts for the suspension system saved a tank. But inasmuch as the [Japanese] have shown considerable reliance on satchel charges thrown under the tank” (7) “The practice of welding spare track blocks on the outside of the turret and on the front slope-plate….and on at least one occasion prevented a 47mm projectile, which hit a track block on a tank turret, from penetrating the armor” (7) In this account a second vehicle hit in approximately the same place by the same type of round but without track blocks added was penetrated and exploded inside the tank. (7) The scale and scope of modifications Armour modifications by the 4th battalion to their M4A3 tanks were: (8) - Additional armour plate was affixed to the front part of the right sponson on 24 tanks mounting flamethrowers. - Forty one tanks had spare track sections welded around the turret and to the front. - Forty seven tanks mounted a spare bogie wheel welded to the front slope plate - Fifteen tanks has a 2 piece sections of channeled steel sheet weleded to the sponsons and a 35mm section cut to shape and bolted to the channel irons. - Three tanks had three sections of plywood installed on their sponsons filled with about 40mm on concrete bolted to brackets welded on to the sponsons and were also considered effective. - Six tanks had 50mm thick timber planking bolted to brackets welded to the hull sides creating a ~75mm thick gap. - Three further tanks used 12mm thick plywood in the same manner. - Fifty four tanks carried the wire mesh cages around all of their hatches. - Forty five tanks had the 76mm ammunition ready box on the floor of the turret basket removed and the 76mm ready racks installed permitting the carrying of 25 more rounds of 76mm ammunition. - Ten tanks had their commandeers cupolas rotated 45 degrees clockwise so that the hatch opened to the rear instead of to the right hand side and thus prevented branches and wires etc Continue reading →

More...