Here it is in six sections because of the 10,000 char limit.

Every infantry unit can for some tasks benefit by working dismounted alongside armoured vehicles and by making routine and expedient use of armoured vehicles for infantry mobility and transport of stores. The initial question to be asked when planning an infantry carrying armoured vehicle is ‘ how many dismountable infantry should it carry ? ’ And the immediate answer that comes to mind is ‘ a complete section/squad ’. The alternate and final answer is probably ‘ a complete squad plus a support element ’.

However infantry are organised and equipped in different ways. Some armies – including the American, British and German – have several types of infantry mounted on armoured vehicles. Firstly they employ a 6- to 8-strong infantry squad in a tracked vehicle armed with a powerful turreted cannon. The vehicle is intended for combat and together with its crew of two or more can function as a weapon team and support the squad after it has dismounted. Units mounted on such vehicles are usually described as armoured infantry.

Secondly there are mechanised infantry units that when dismounted are expected to sometimes operate independent of fire support from their vehicle. Each mechanised squad typically includes a dismountable weapon team, and a whole squad of 8 to 10 or sometimes as many as 12 dismounts is transported in one tracked or wheeled armoured vehicle, or in two such vehicles.

Thirdly for operational and local mobility it can be useful to provide light infantry with armoured transport vehicles. Light infantry squads in most industrial armies vary in size from as large 13 in the USMC to as small as 8 in other forces. The larger squads of 10 or 12 often include a weapons team of three or four which may deploy close to or at some distance from the rest of the squad. Similar to mechanised infantry the whole squad may be transported in one armoured vehicle. Alternatively 8 or 9 infantry could be in one vehicle with a 3- or 4-man weapon team in another vehicle. Forces organised with smaller light infantry squads of 9 or fewer dismounts usually employ those squads in conjunction with weapon teams detached from platoon and company level that are transported in the same or accompanying vehicles.

Is it necessary to provide different vehicles for armoured and mechanised infantry, and similarly for mechanised and light infantry ? The common needs applying across different types of organisation are that a mounted squad or part squad be small enough to restrain the size of its transport vehicle, big enough to put a useful number of infantry on the ground, small enough to enable some commonality of sub-unit doctrine across different types of infantry, and big enough to limit average procurement and operating costs for each crew and infantry seat.

Those size-related considerations together with the attributes of protection, mobility and armament and dollar costs are essentially determined by doctrine and the extent of interaction between infantry and their vehicle in combat and in the vicinity of combat. If doctrine has established a need for three distinct types of infantry based on such interaction, then it is probable that three distinct types of squad carrying armoured vehicles will be required. However, for flexibility those vehicles - or at least those intended for mechanised and light infantry - should be able to transport all manner of customary squads.

Most seats for dismounts are arranged to face inwards or outwards. With each seat shock-resistant and spall-protected the length of an armoured transport vehicle’s cabin can increase by at least 70cm for each pair of seats. From an organizational perspective, having seats in one vehicle for 10 infantry would enable transport of a 6-man to 8-man squad or part squad plus a 4-man to 2-man weapon or command team or other specialised element Seating for twelve infantry might seem to be a reasonable maximum as it would allow for a large 12-man squad, or an 8-man squad plus a 4-man weapon team or other element, or two 6-man squads.

But if 12 why not 13 to provide for squads organised with three 4-man teams and a squad commander as in the USMC ? There is a practical limit beyond which the dimensions of a vehicle become so large and its armour protection so stretched that it becomes an unnecessarily bulky and vulnerable target. Also it is impractical to squeeze extra infantry into a small vehicle by using foldable jump seats instead of shock-resistant and contoured seating. One certain result of the former is to deliver infantry whose fitness has been degraded by the inadequacies of cramped and uncomfortable seats.

Here in order to simplify things it is supposed that a squad carrying armoured vehicle should be restricted in size and designed to carry its basic crew and at least eight dismounts. That minimum capacity would provide for any squad - or part squad - up to 8-strong, or alternatively two 4-man weapon teams or other combinations such as a weapon team with an engineer, HQ or other element.

An alternate minimum of 10 would enable transport of an 8-man squad plus a 2-man element but would still not suit the needs of the USMC. Transport of its complete 13-man squad implies a needed capacity for up to 15 dismounts and a large increase in vehicle size. Hence in order to reduce potential vulnerability and despite any loss of co-ordination it is also supposed here that the maximum capacity for an infantry carrying armoured vehicle should be the vehicle crew plus 12 dismounts.

The capability to deploy and manoeuvre powerful weapons is a role for purpose-designed AFVs that have the space and weight arrangements to keep such weapons in operation. Infantry-carrying vehicles - including to some extent the AIFV - need a restrained form of armament because the weight and space of a substantial armament modifies the armour and protection that can be provided for the crew and mounted infantry. Prospective and actual use of weapons can also distract a vehicle commander, and additionally encourage inappropriate manoeuvre in hazardous zones.

The vehicles considered are the tracked and wheeled light and medium APCs used mainly by mechanised infantry, the wheeled PMV used by light infantry, and the medium tracked AIFV and the heavy BW used by armoured infantry.

APC – General

The Armoured Personnel Carrier was mainly developed to transport infantry and their equipment and stores in the vicinity of - but not actually into - close combat. That covers transport of mechanised infantry and occasionally light infantry but not armoured infantry. However, roles and priorities vary and some armies persist in confusing the APC concept with that of an AIFV suitable for use by armoured infantry.

Early APCs such as the German SdKfz 251 and US M3 halftracks used during the 1940s were open-topped but - within a loaded weight of about 10 tonnes – they could carry an upper belt of frontal and side armour protection equivalent to about S-4659 Level 2 standard. Their typical armament consisted of one or more MMGs on pintles attached to the vehicle’s front or sides, and sometimes a HMG on a pintle or ringmount.

More recently airburst and other fuses enable artillery shells, rockets and bombs to reliably produce downward and radial destructive affects instead of cratering the landscape. Open-top APCs may also be subject to overhead attack by EFP, liquids, aerosols and gas. And every APC is liable to all-round roof to wheel attack by kinetic and chemical energy warheads delivered by guided missiles, direct-fire guns and rockets. Additional attack especially on vehicle sides and belly can be made by bomblets and buried and off-route blast and EFP mines detonated by pressure-plate, tilt-rod, vehicle counters and other sensors or remote command. Hence most recent APCs have a fully enclosed 6-sided armoured body, and many have a roof-mounted turret for observation and defensive fire. Protection when closed up can also include filtered over-pressurisation.

The deployment and manoeuvering of powerful weapons is a task for purpose-designed AFVs that can be built with the space and weight arrangements to keep such weapons in operation. And it can be supposed that the mobile forces of an industrialised army will be equipped with a mix of small and larger AFVs. Also access to and movement within operational areas is important for all vehicles. Hence, the attributes of an infantry squad-carrying vehicle or APC can be clearly ranked in order as protection, mobility, armament.