An Cosantóir

www.military.ie the defence forces magazine | 21 the centre of a water obstacle. This wet gap option can span up to 44 metres. Before either of these options are chosen however, the ground must be surveyed to ensure the area is suitable. These surveys can go into enormous detail, especially when span- ning a river, where one of the items of information the team needs to know is the speed of flow of the water. If it's fast the engineers will have to decide if the anchoring system will be strong enough to hold the floating 460kg bridge in posi- tion. (The anchors are essentially stakes that are strategically placed in the ground and then attached to the bridge via cables.) With the speed of assembly that's required under stress- ful conditions, there is of course a trade-off. This comes in the size of load that the bridge can handle. The IAB can take a maximum weight of 135kg, so, for safety, only one person crosses the bridge at a time, con- trolled by the combat engineer at the foot of the bridge. This sys- tem means a standard infantry platoon can cross a 40m obstacle in four minutes, still a significant achievement if you consider that unspanned it could have delayed the troops by an hour or more, depending on the location. The IAB is about more than just aluminium tubing used to bridge a gap. It's a combat system that uses hardware, specialised meth- ods and trained personnel to cross an obstacle. From the dispersed, camouflaged bridging panels in their hides, to the combat engi- neers that are trained to construct the bridge alongside infantry executing an attack, the IAB can be a significant force multiplier when needed. A well trained crew combining command, delegation and hard work is required to place the bridge accurately on the far bank. There is one hollow, aluminium pontoon for each complete IAB unit to float on. The anchoring system also attaches to the pontoon, providing more stability in fast flowing water. This close-up shows how the panels are connected. The black handles would be in the forward position when the panels are being moved from the hides. The first team called forward places the roller assembly into the ground. It's a crucial first step because if it's placed in the wrong location or angle, then the bridge will have to be disassembled with a follow-on delay. Next up after the roller are the panels, arriving in a pre-planned order. The number of panels used will depend on the size of the obstacle. The roller, which also acts as a fulcrum in the placement of the IAB. Before the roller is removed, final adjustments are made by the combat engineers. At all times, those not directly involved are covering off, waiting for the next stage of the operation. With the roller removed, the bridge can be crossed at a rate of eight troops per minute.

• Cover