Montreal Locomotive Works Sexton

     Notes: Though the Canadians and British liked the US M-7 Priest self-propelled howitzer, the 105mm howitzer was not a standard issue gun for the Canadians or British during World War 2, which led to supply problems.  The Canadian MoD therefore decided to build a self-propelled howitzer based on the Priest, but using the 25-pounder field gun that was standard with Canadian and British forces.  This vehicle became the Sexton; in addition to the Canadian Army, the Sexton was used by the British (in the later years of the war) and several other Commonwealth nations used the Sexton.  The last known user was India, who used the Sexton II and the Sexton GPO until the mid-1980s, and still keeps most of their Sexton force in functional storage.

     The Sexton was actually three vehicles, all based around the 25-pounder gun.  The Australians also built an SPH based around the 25-pounder gun (the Yeremba), but based on yet a different chassis.  The Sexton I was based on the Ram tank; the Sexton II was based on the M-3A1 Lee hull, and the Sexton GPO was a mobile FDC used with Sexton-equipped units (and will be found in Canadian Artillery Support Vehicles).  At any rate, the Sexton ended up looking basically the same (since all three had a Sherman chassis), and differed only in small details.

     The Sexton I is based on a Ram tank chassis, which was in turn based on stock M-4 Sherman hulls. Only 175 were built (with the remaining being Sexton IIs or GPOs).  The vehicle had a crew of six: driver, commander, gunner, gun-layer, loader, and radio operator.  As with most such vehicles, the interior is cramped, most internal space taken up with firing equipment, fuzes, charge bags, and the shells themselves.  The Sexton I used a British (later Canadian)-built engine, a Continental RG-75-C1 gasoline engine developing 400 horsepower, and with a manual transmission and with tillers for steering.  The Sexton II upped the ante to a Continental RG75 developing 475 horsepower, again with the manual transmission and tiller transmission.  The engine is at the rear on an extended chassis deck.  The Sexton used the VVSS suspension pioneered on the M-3 Grant and Lee and made famous by the M-4 Sherman.  There are no shock absorbers, as shock absorption is included in the VVSS suspension.  For use with the Sexton GPO, the Sextons had three hookups for field telephones, and also carried three field telephones on the vehicle in addition to their radios.

     The main armament consisted of a self-powered 25-pounder gun.  The gun has a depression of -9 degrees and an elevation of +40 degrees; it could also traverse 15 degrees right and 25 degrees left.  This gun movement, however, was manual, done by hand wheels. Depression was more than sufficient for direct fire, and the Sexton sometimes carried anti-armor shells and was used as a tank destroyer. Sextons were also sometimes used as antiaircraft artillery. The howitzer had to be extensively modified to take the 25-pounder gun, particularly in the recoil dampening department and to compensate for a lack of gun trails.  Two Bren guns were provided to the crew, though they did not have actual mounts.  No pulpit-type mount, like on the US M-7 Priest, was present on the Sexton. The Sexton did, however, carry 50 magazines for its Bren guns.  Rudimentary (even for the time) aiming tools were provided; however, most firing calculations were carried out in the GPO.  There was no overhead protection, other than tarps which could be mounted on small bows.  Most of the crew was in the open area around the gun; however, the driver was in the front of the superstructure on the right side, and had an open window in front of him, with an armored shutter which had a vision slit in it.

     The Australian Yeramba took the same idea, using the same 25-pounder gun/howitzer.  The Yeramba was based on a modification of the M-3 Grant tank, however, with it’s standard guns and turret removed.  The Australians took the best parts of the Sherman suspension and melded them with the Grant chassis; the Americans referred to the actual Yeremba tank as the M-3A5 Grant. The modifications included the HVSS suspension of later Sherman versions. The Yeremba is a post-war design, not produced until 1950-52, and in service only until 1957; it was, however, the cheapest solution the Australians had to the lack of mobile artillery for a few years.   The driver is in front under the main gun and the commander and loader have positions to occupy when they are traveling.    A pair of GM-6-71 diesels totaling 375 horsepower were installed in place of the gasoline engine. A Sherman-type suspension replaced the Grant’s suspension, and a more substantial muzzle brake was added to the gun muzzle. The Yerambas were declared obsolete in 1957, and never saw any combat service, with only 14 such conversions taking place.  An advantage had by the Yeramba is somewhat heavier armor; this includes a more sharply-raked glacis.

     In all cases, the armor was greatly reduced to accommodate the heavy weight of the main gun and still keep a decent speed, and because the vehicles were not expected to have toe-to-toe slugfests with enemy armor.  One Bren was placed in a small swiveling sponson up front; the other had no actual mount. 

     During and after World War 2, some 72 Sextons were converted by the Canadians to Kangaroo APCs.  A special variant of the Sexton was developed as one of Hobart’s Funnies; this had a screen which was erected for swimming as well as bilge pumps, and used on Gold and Sword beaches and most of the European Invasion campaign.  Most of them did make it ashore, either by swimming or by landing ships. (These may be simulated by adding $400 to the cost of the Sexton Mk II and using a swimming speed of 4.)