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1

Tuesday, June 23rd 2009, 2:26pm

USMC tank destroyer

In 1937, a bright spark at the Department of the Navy, where a second order for the M2A4 light tank was being changed to an order for the current M3 light tank, noticed that the dimensions and weight of the Army's M-8 tank destroyer seemed to indicate that it should float (assuming that the hull was sealed, of course). A request was sent to the US Wheel Track Laying Corporation for a single example vehicle with a sealed hull. Christie responded with a vehicle that not only had a sealed hull but also had a pair of auxiliary propellers to increase it's speed in the water.


Vehicle Name M-8B
Vehicle Type Amphibious tank destroyer

Length 5.60 meters
Width 2.50 meters
Height 2.53 meters

Crew 4.00 men
Passengers 0.00 men

Weight Breakdown
Crew Weight 0.72 metric tons
Passenger Weight 0.00 metric tons
Miscellaneous Weight 0.09 metric tons
Armor Weight 6.39 metric tons
Armament Weight 0.34 metric tons
Ammunition Weight 0.42 metric tons
Engine Weight 0.63 metric tons
Fuel Weight 0.46 metric tons
APU Weight 0.00 metric tons
Energy Bank Weight 0.04 metric tons
Transmission Weight 0.68 metric tons
Amphibious Equipment Weight 0.13 metric tons
Suspension Weight 1.43 metric tons
Track Weight 1.57 metric tons
Road Wheel Weight 0.54 metric tons
Applique Armor Package A 0.00 metric tons
Applique Armor Package B 0.00 metric tons
Cargo Payload 0.00 metric tons

Mobility and Performance Breakdown

Engine 300.00 horsepower
Fuel Capacity 160.00 gallons
Maximum Hull Speed (water) 6.61 MPH

Baseline Upgraded (A) Upgraded (A+B)
Combat Weight 13.42 13.42 13.42 metric tons
Growth Capability (Transmission) 12.76 12.76 12.76 metric tons
Growth Capability (Suspension) 6.58 6.58 6.58 metric tons
Ground Pressure 11.43 11.43 11.43 PSI
Power/Weight Ratio 22.36 22.36 22.36 hp/metric ton
Top Speed 40.52 40.52 40.52 MPH
Operating Range 192.08 192.08 192.08 miles

Amphibious Performance Breakdown
Density of Vehicle 0.55 0.55 0.55 g/cm3
Vehicle Freeboard (Transiting) 0.06 0.06 0.06 meters
Vehicle Freeboard (Dropped In) -0.53 -0.53 -0.53 meters
Vehicle Draft (Transiting) 1.56 1.56 1.56 meters
Vehicle Draft (Dropped in) 2.15 2.15 2.15 meters
Water Speed 5.43 5.43 5.43 MPH
Operating Range In Water 35.02 35.02 35.02 miles

Armament Breakdown
Hull Turret
Rifle Calibre MGs 0.00 1.00
HMGs 0.00 0.00

Hull Turret Total
ATGMs 0.00 0.00 0.00 rounds stowed
Rifle Calibre 0.00 1,200.00 1,200.00 rounds stowed
HMG Calibre 0.00 0.00 0.00 rounds stowed

Calibre (mm) # in Hull # in Turret Rounds (hull) Rounds (Turret)
Cannon/Gun 1 50.80 0.00 1.00 36 48
Cannon/Gun 2 0.00 0.00 0.00 0 0

BASELINE PROTECTION LEVELS
KE (mm) HEAT (mm) KE Resistance HEAT Resistance
Front Hull Armor 23.51 23.51 Resistant to 12.7 Penetratable by Virtually Anything
Side Hull Armor 13.11 13.11 Resistant to 5.56 Penetratable by Virtually Anything
Rear Hull Armor 12.92 12.92 Resistant to 5.56 Penetratable by Virtually Anything
Top Hull Armor 12.70 12.70 Resistant to 5.56 Penetratable by Virtually Anything
Hull Floor Armor 12.70 12.70 Resistant to 5.56 Penetratable by Virtually Anything

KE (mm) HEAT (mm) KE Resistance HEAT Resistance
Front Turret Armor 27.03 27.03 Resistant to 12.7 Penetratable by Virtually Anything
Side Turret Armor 13.52 13.52 Resistant to 5.56 Penetratable by Virtually Anything
Rear Turret Armor 13.02 13.02 Resistant to 5.56 Penetratable by Virtually Anything
Top Turret Armor 0.00 0.00 Penetratable by Virtually Anything Penetratable by Virtually Anything

2

Tuesday, June 23rd 2009, 2:30pm

Iiiiiiinteresting. Now that would have made for a useful addition to the WWII US order of battle...

3

Tuesday, June 23rd 2009, 2:39pm

Yeah, it might have at that. I was going over the M-8 for posting to the new US AFV thread I'd added yesterday when I noticed that it floated like a cork (or would if provisions for doing so were added). The US army is unlikely to order any of this model (at least at current), but the USMC might well order some instead of some of the M-3s it was going to get. After all, the M-8B carries a heavier main gun, floats, and is lighter and faster than the M-3, though the M-3 is better armored and carries more machineguns and ammo for them. It's amphibious nature will make beach landings easier, since it can be launched from a distance instead of requiring LCTs to take it to the beach.

4

Wednesday, June 24th 2009, 12:30pm

A very interesting idea. I think the USMC would like such a vehicle, would be very suitable for tank destroying and as a general light tank.

5

Wednesday, June 24th 2009, 1:54pm

In service, it would essentially be used as a light tank, the USMC doesn't have enough tanks that it can have some specialized for tank destroying and others for infantry support. Besides, at this point in time, the only other type of tank the USMC has are light tanks of the M2A4 type, so armament-wise this is almost a medium tank. :)

Kaiser Kirk

Lightbringer and former European Imperialist

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6

Sunday, June 28th 2009, 5:47am

The Dutch certainly believe that even light armored support is far superior to no armored support for their marines. Except we went with a 23mm autocannon for the first models, TD and SPG variants will wait until the first model is in service longer and bugs found / need identified.