Crossing Bridges
In Gunship, bridges are only shown over small waterways and are always in ruins. They aren't in fact bridges at all. When larger waterways are present, they will effectively divide the map into fixed zones for ground units, with no means of movement between. This was how Gunship was written. Now, thanks to the pioneering work done on terrain tiles by fng2k, usable bridges are possible over the larger waterways.
The new Bridge Mod files can be downloaded from http://www.simwarrior.com/gunship/utilities/gsbridgemod_v1.exe
Paste the 4 files into your Gunship folder (full installation instructions are included).
The new files change some of the Gunship terrain tiles to show a bridge spanning the river. Whenever a map uses one of these tiles, the bridge is in place, so this small change will also insert usable bridges into already existing missions. To find new crossable bridges, use Battle Builder and check the areas where large rivers are visible.
Forming Columns
Programming units to cross the bridge requires delicate handling and can only be done using WP orders. I've tried various Logic commands, but without much repeatable success. Logic Recon can sometimes get them across, but platoons are reluctant to form column in the presence of a located enemy. Vehicles left to their own devices will gladly plunge into the river and will usually stay there. The unit must cross in column and the column has to be correctly formed. Identify the start and end points of the bridge, using any mapping method you prefer. The X or Y co-ordinate running the length of the bridge is critical and will have to be accurately determined to within 10 or 20 metres. Some trial and error is needed here as the object is to get the entire platoon safely from one end to the other.
A correctly formed column should put all the vehicles into a straight line following the leader. If your column is ragged and vehicles tend to spill over the sides of the bridge, it may be that the column is not correctly formed. When a platoon forms column (or any other formation), the 1st vehicle (platoon leader) moves off first and takes point. The remainder of the platoon then moves off and falls in behind. Problems occur because the correct vehicle order for a column is 1, 3, 2, 4, 5 and if the platoon tries to form column while advancing too fast or following a change of direction, vehicles may not be able to get into position before they hit the bridge.
The diagram shows the evolution required to form column from line. Vehicles 2 and 3 have the furthest to go and are at risk of colliding with 4 and 5. A collision usually results in both vehicles changing direction and loosing more time. The column will not slow down to allow stragglers to catch up, nor will vehicles remain in incorrect slots. The result will be large gaps and vehicles two abreast, trying to overtake.
This example assumes that all vehicles started in a strict line. But, if vehicle 3 had held back or 4 had advanced due to terrain, then the job would be even harder.
To avoid this, allow the platoon to form column well before the bridge and then approach in a relatively straight line to a WP at least 100m back from its forward edge. The resulting pause at the WP, just before crossing, should allow the platoon to form into the correct order before moving off. Make the approach at Medium speed, as this still allows stragglers to speed up and get into position. For the same reason, try to avoid abrupt changes of direction close to the crossing point.
If you start the platoon in column in the platoon header, reversing the direction of facing will allow them to move off smoothly in the correct column order. When the column is formed correctly, bridges can be successfully crossed at medium speed.
Fast speed can work, but will be less reliable. It only takes one vehicle to jink right instead of left to avoid a tree and cause a collision. One bump can disrupt the entire formation and at Fast speed they have no way of correcting it.
Set Delays
This is fine if you only have one platoon crossing, but additional care is needed when multiple units are used. One method is to use use the same bridge WPs for all units and use the setdelaytime command to space the units out.
A word of caution. If the delay is 60 seconds or more, the unit will abandon its travel formation during the halt and adopt a defensive posture, dependant upon terrain. The travel formation will then be resumed when the unit restarts its movement. If the unit is close to the bridge as it moves off and reforms, it may well run out of room. So, if you want a unit to travel in column and retain the column formation during the halt, the delay must not exceed 59 seconds.
Stagger Units
The other method is to stagger the platoon co-ordinates on the approach to the bridge. This is more difficult to achieve, but can produce a much faster moving convoy. The trick is to prevent the front of each platoon catching the tail of the previous one at WPs, as the rear platoon will then displace left or right and probably miss the bridge. The spacing between platoons should be enough to accommodate the previous platoon column, plus a buffer of around 50 metres.
However, if both the front and rear platoons arrive at their WPs at the same time, then this spacing may need to be increased, as the lead vehicles in each platoon will both move off at the same time. The lead vehicle of the rear platoon will have covered the 50 metres gap before the last vehicle of the front platoon has moved off. The WP at the far end of the bridge may also need to be moved further away, or the end of the platoon column will still be on the bridge when the platoon halts. Also pay attention to the different speeds of ground vehicles. If you put the slow platoons up front, you will need to use much larger gaps. Some Russian Tank and IFV HQ Platoons are mixed and need to be watched carefully as the lead vehicles will race ahead and leave the slower ZSU-23 trailing behind.
If space allows, when forming multiple columns always try to start them on a common X or Y heading. Trying to form staggered columns on a diagonal requires much more work.
The mission 'Kelly's Heroes' uses three crossable bridges for the attacking force and can be downloaded HERE.
Why do columns use a different order.
All the formations used in Gunship are a legacy from M1Tank Platoon. A platoon of 4 M1A2s is split into two sections of 2, with the second section leader in vehicle 2. Formations such as column correctly reflect this, with the first section, vehicles 1 and 3, being followed by the second section, vehicles 2 and 4. See the Vehicles and Platoons section.