Fireflyweb:

Retype of the conversion instructions for:

Medium Tanks, M4 M4A3 and M4A3W (w/75mm Gun) - present British Conversion vs., Conversion for U.S. Troops.

My comments are in brackets. All original spellings and punctuation forms have been kept.

Note "British English" use of "ise" rather than "ize" perhaps indicating a UK author for this text? E.g. "utilise" rather than "utilize" in opening paragraph below. Or it may be US originated, but written for a British audience as there are several things that look like they are "translations!" from US technical language to British terms (E.G. Para 6b, "elevation quadrant, K-9 ("clino" bracket) and Pt II, Para 2 G "on medium tanks, M4 (MK I)).

Note that the turret details and some of the hull details pertaining to the rolled hull M4 and dry stowage M4A3 should apply to the M4A4 (Sherman VC) conversions as well.

There is listed below an analysis of the various operations in the 17-pounder conversion of the M4 series medium tanks for US troops that differ from the conversion currently being made in British arsenals. Some additional operations are listed that should be incorporated in the conversion in order to permit US troops to employ equipment they are now provided with and trained to utilise, but a majority of the changes in the conversion they listed below call for the omission of operations now being made.

I Turret

1. Remove radio and radio mounting base and relocate (on 1/2" spacer (approx. 12.5mm)) in armoured box on the rear of the turret. Armoured box should be 2 1/2" longer and 3/4" wider (approx. 62.5mm and 19mm) than the box currently employed. A 2" approx. (50mm) increase in the length of the box should be obtained by decreasing the thickness of the end plates of the box from 2" to 1" (approx. 50mm to 25mm). The front top mounting strip of the box should be narrowed 1/2" (approx. 12.5mm) and the bottom edge bevelled approximately one half of the thickness of the plate. Two handles should be provided on the top plate. (The phantom antenna should be discarded).

2. The following brackets on the turret wall should be removed:

a. Radio mounting bracket.

b. Tank commanders convoy seat.

c. Utility-lite pistol grip, w/real.

d. Ventilation fan.

e. Sun-machine gun bracket on rear turret wall (M4 and M4A3 only) (suggesting M4A3W did not have this already?).

3. All other stowage brackets on the turret wall of US equipped tanks should be included in the conversion:

a. Binocular carrying case on right turret wall.

b. Instrument light bracket for azimuth indicator on right turret wall.

c. Three (30 canteen racks on left side of turret.

d. Two (2) flashlight brackets - one (1) on top front turret wall, one (1) on right rear turret wall.

e. Bolt and tool box for coaxial MG on left turret wall (M4A3W only).

f. Periscope bracket on right rear turret wall.

g. Cal. .50 barrel bracket on right top of turret basket (M4A3W only) (12.5mm M2 HMG).

4. The following items currently included in the conversion of the tank are not required:

a. Flare pistol bracket on right rear turret wall.

b. Flare pistol ammunition box on right front turret wall.

c. Battery balancer on left rear turret wall.

d. Caliber .50 (12.5mm M2 HMG) ammunition box rack on right rear turret wall.

e. Stowage racks for "Tommy Gun Magazines", mittens, First Aid kits, and lamp in center rear of turret. (M1A1 or M1 .45 Cal Thompson SMG).

f. Microphone outlet ("Tannoy unit") mounted on radio junction box.

g. Range finder mount on tank commanders hatch ring, and range finder stowage bracket on left front top of turret bracket.

h. Variometer unit below antenna.

i. Sun compass bracket on right outside of turret. (showing that this desert fitting from original UK requirements in 1942 was still around on many tanks!).

5. All other parts of the turret conversion should remain the same, including:

a. The installation of the loader's escape hatch (on tanks not so equipped). (I.e. those tanks with the oval loaders hatch in the high bustle turret or a retrofitted on earlier vehicles - does anyone have a photo to prove this was done in practice, rather than planned for?)

b. The 17-pounder gun and gun mount (w/firing lamp).

c. The tank commanders seat and the loaders seat with alternative mounting brackets.

d. Large sized British grenade box on left front turret wall.

e. Small sized grenade box on turret floor.

f. Two inch smoke bomb ammunition rack on left turret wall.

g. Four pound CO2 fire extinguisher to right of gunners seat.

h. Three (3) periscope boxes restowed loose in sponsons.

i. The stowage straps on the left front of the outside of the turret.

j. The cover for the 2" (50mm) smoke mortar aperture.

k. The modification of slip ring box ("rotary base") and rewiring of intercommunication circuits.

l. Modification of pistol port handle. (Note many Shermans had this omitted or welded up if made in 1943 into early 1944, so this may not have been required on some vehicles).

6. The following additions should be made to the present British conversion of the turret:

a. Relocation of the caliber .50 machine gun mounting brackets (pintle socket and clamp) from the rear of the turret bulge to the rear of the armoured radio box. The caliber .50 barrel brackets should be discarded.

b. Installation of mounting pad for elevation quadrant, K-9 ("clino" bracket), and instrument light bracket on top right of 17-pounder gun mount to left of normal position of gunner's head - mounting pad and bracket to be removed from 75mm gun mount. At least 1/2in (12.5mm) clearance should be left under the mounting pad in order to permit the application of lock nuts when the elevation quadrant is installed.

II Hull

1. The following items currently added to the exterior of the hull should be omitted:

a. Bracket for driver's rear view mirror.

b. Two methyl bromide fire extinguishers on rear hull top.

c. Towing hook (US type towing pintle should not be removed).

d. Smoke generator. (suggesting these were still being fitted in 1945).

e. Transportation shackles.

f. Wading equipment. (suggesting these were still being fitted in 1945, but it is often absent in photos in 1945).

g. First Aid box.

h. Blanket bin on rear of hull (probably the greatcoat stowage bin shown on the TM IC stowage diagrams).

2. The remaining items currently added to the exterior of the hull should be installed, including:

a. Bracket for idler adjusting wrench (on tanks not so equipped).

b. Plug over bow machine gun hole.

c. Bracket for 17-pounder cleaning rods.

d. Stowage straps on left rear hull top.

e. Brackets on hull front plate for spare track blocks.

f. 17-pounder travel lock on left rear hull top. (Note no mention of use of the glacis barrel clamp fitted to many Shermans).

g. Convoy tail light (on medium tanks, M4 (Mk I) only).

h. Stowage bin on top right rear of hull. On medium tank, M4A3 (Mk IV), bin should be relocated several inches forward in order to permit removal of rear hull top plate.

3. The only change desired in the conversion of the interior of the hull equipped with armour protected ammunition stowage is the omission of the two (2) respirator element stowage boxes from the right sponson. No specific stowage brackets remain for calibre .30 spare barrels (M1919 .762mm MG), calibre .30 tripod, M2, 5-gal water cans, and the gunner's quadrant, however, these items can be stowed in the sponsons in the bins provided for British equipment. The engine emergency stop button should be installed on tanks not so equipped.

4. In the conversion of the interior of a hull equipped with water protected ammunition stowage:

a. No change is desired in the general arrangement of the sponsons. The three (3) periscope stowage boxes removed from the turret basket floor should be restowed loose in the space available in the right sponson.

b. The normal procedure of cleaning out the hull and welding the escape hatch shut should be followed (including the necessary relocation of the 10-lb. CO2 fire extinguisher and the generator), and the calibre .30 Bow machine gun ammunition ready rack cut down to permit installation of the fourteen (14) round 17-pounder ammunition bin.

c. The track parts and grease stowage bins in the right rear lower hull should be discarded.

d. The tract tool box in the left rear lower hull should be relocated in the right lower hull behind the rear twenty (20) round 17-pounder ammunition bin.

e. The combination hood and periscope stowage box over the transmission should be retained.

f. The four (4) lb. CO2 fire extinguisher on the right side of the transmission should be relocated in the normal manner.

Document classified RESTRICTED. No other information is on the sheets.

Typed by Bill Hayward 30th Dec 01.