WW2 scenes

Here's another example of lumber applied to American tanks in the Pacific. Did Japanese use magnetic mines? So far I can't say for certain, but it seems a plausible reason for boards on a tank.

Kwajalein Atoll. Private First Class N. E. Carling stands beside the American M4 Sherman medium tank "Killer" on which is mounted a knocked-out Japanese Type 94 tankette / light tank.
https://en.wikipedia.org/wiki/Tanks_in_the_Japanese_Army#/media/File:M4-sherman-killer-kwajalein.gif

Here you go @NebrHogger old mate:
In the Island hopping campaigns of the War in the Pacific, the major threat to tanks of the United States Marine Corps (USMC) was Japanese infantry. The stubborn island defenders had various grenades and mines at their disposal. These were often used in suicidal point blank ‘Kamikaze’ style attacks with infantry charging the American tanks armed only with an explosive device. The attackers would also climb aboard the tanks and claw open hatches so they could throw grenades and explosives inside.

By the Okinawa campaign of 1945, the tactics of the Japanese had been identified. Come May of that year, it was determined that at least 64 tanks had been knocked out by infantry & mine attacks.

Men of the United States Army’s 193rd Tank Battalion recorded the attack method as such:

“Japanese squads of three-to-nine men attacked individual tanks. Each man in the squad filled a role. One man threw smoke grenades to blind a targeted tank. The next man threw fragmentation grenades to force the tank’s crew to close their hatches. Another man placed a mine on the tank’s track to immobilize it. A final man placed a mine or explosive charge directly on the tank to attempt to destroy the tank.”

These direct, ferocious and desperate assaults led to a number of unique improvisations in appliqué armor by the USMC. The US Army would also employ these improvisations as more troops and tanks from this branch were deployed to the Pacific.

Wooden Planks
This was the first attempt at providing protection against magnetic mines, namely the Type 99 Anti-Tank Magnetic Mine, or the non-magnetic Type 93 Anti-Tank Mine. It also served as protection from the ‘lunge mine’.

In most cases, the wooden planks were bolted onto the sponson sides with no gap between the wood and the steel. In some cases, the application was a little more extensive, however. In these cases, four small sections of wood were bolted to the outside of the sponsons. U-shaped bars welded to the hull sides were also used. The length of the planks used varied, but on all tanks, it was cut to fit the shape of the hull up to the weld of the upper glacis. The framework underneath gave around 2 in/5 cm of clearance from the hull side, granting a bit of protection from shaped charge munitions which had an effective depth of just 2 inches or so. The gap around the exterior perimeter of the appliqué was covered with smaller planks to stop grenades and other explosives from being dropped into the void.

Later, the planks would be added to the suspension bogies to guard against Japanese troops throwing explosives at the running gear and immobilising the tank. The planks were bolted directly to the bogie units. In this theatre, an immobilised tank was a dead tank. It would be swarmed by suicidal Japanese troops and who could force open hatches. In some cases, the wood would also be added to the front of the tank, covering the upper glacis, but this is a rarer configuration.
http://www.tanks-encyclopedia.com/ww2-usa-improvised-armor-on-m4-shermans-in-the-pto/

Great post! I had heard of "lunge mines" or pole mines if you'd rather but missed mention of magnetic mines.

There was an instance in Viet Nam where a strong NVA force attacked an American position, trapping 2 Marines in a listening post. A tank went out to successfully rescue them, but NVA swarmed the tank trying to blow the hatches open. Artillery in the position held the trails up with ammo crates so the barrels could be depressed enough to dust the tank off with canister. Everybody in the tank made it okay, but I was told clean underwear was required for them.