Regards the short article on page 5 on improvised armor for Sherman tanks.
The Marines had been adding 2 x 12 oak planks to the side of their Sherman’s since the Mariannas campaigns. The planks were attached to angle iron that had been welded to the side of the tank. The oak planks served to defeat the Japanese magnetic anti tanks and by being attached to the angle iron a dead space was created to help defeat any satchel type charges that might be placed or held against the planks.
Some of M4s had large spikes or cages welded around the driver hatches to help defeat anti armor charges that might be thrown up onto the Sherman. The armor around the hatches tended to be thinner than normal and these countermeasures served to help defeat the anti armor charges.
Of course sections of track, bogie wheels, oak planks and anything else that could be scrounged were often welded or attached to the front of the Sherman to help protect against Jap anti-tank fire.
One other comment on Okinawa the Marine had mostly M4A3 Shermans (gasoline) with the sloped glacis plate along with a few of the M4A2(diesel) version. The Army tank battalions were equipped with the cast composite hulls. The Marine tanks would usually shrug off the Japanese anti tank rounds. The Army tanks on the other hand were consistently penetrated by the Jap anti tank guns.
http://www.tanks-encyclopedia.com/ww2/US/M4_Sherman.php scroll down about half way to find illustrations of Marine tanks King Kong and Jungle Jim with the oak planks.
I have an interesting book entitled “Marine Tank Battles of World War II. Who knew,eh? Short version of the book the Marines used the tanks as mobile pillboxes in the infantry support role mainly. There were a few encounters with Japanese armor and the Japanese always fared very badly when taking on Shermans. The best of the Jap tanks was roughly equivalent to early versions of the M3 Stuart.
Regards
alfa6 ;>}
I note that Patton forbade such augmentation because engines were inadequate. But he was rampaging across-country, whereas the Marines were using them, as you put it, as mobile pillboxes. Was that why they were successful in the Pacific?