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Engineer Gap Crossing Planning. Instructor: . Purpose of the Training. Teach students the critical information requirements to properly plan for a wet gap crossing. Source Data. FM 3-90.12, Combined Arms Gap-Crossing Operations, Jul 08 FM 90-13, River Crossing Operations, Jan 98
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Engineer Gap Crossing Planning Instructor:
Purpose of the Training • Teach students the critical information requirements to properly plan for a wet gap crossing.
Source Data • FM 3-90.12, Combined Arms Gap-Crossing Operations, Jul 08 • FM 90-13, River Crossing Operations, Jan 98 • TC 5-210, Chapter 4, Military Float Bridging Equipment, Dec 88 • Google Earth image
Practical Exercise Walk-Though • Mission: Construct a ribbon raft • Location: Big Piney River (NA 543281) • Size of Gap: 640 feet wide (195 meters) • Depth: 4 feet deep at its lowest point (1.2 m) • Current Velocity: 4 feet per second (1.2 m/s) • Classification Required: 60 • Time: Start time - 2300 hrs
Launch Restrictions • The ideal launch is a Free Launch • Increased speed to download trucks
Practical Exercise 2 • Mission: Transport an Combined Arms Battalion (CAB) of a Heavy Brigade Combat Team (HBCT) across a wet gap via rafts using a corps Improved Ribbon Bridge Company (IRBC). Time is of the essence. • Crossing site survey data: • River velocity at the crossing site is moving at 4 fps (1.2 m/s) • River width is 263 meters • River frontage at crossing site is 100 meters • The unit has only been allocated 1 crossing site • Determine the unit’s crossing time. • Crossing starts at 2100 hours
Raft Crossing Capabilities 6 min to land, download, turn around 263 meters Moving at 4.5 m/s 6 min to upload
PE Solution X 1.5 (if night) 46 (assuming 7 bay rafts) 3 x 4 x 1 x 1 X 1.5 (if night) Crossing time for an HBCT CAB is 5.75 hours Starting to cross at 21:00 means the unit will be complete by 02:45 hours # of raft trips required # of round trips per hour x # of rafts per centerline x # of centerlines per crossing site x # of crossing sites
Purpose of the Program • To automate the tactical and operational engineer’s planning for gap crossing operations, in order to provide for quicker responses to planning questions. • Blue cells are the only ones that you need to put data into. The white cells are formulas or baseline data.
Example Crossing Problem • Situation: • Your unit is in hostile terrain but is not currently in contact. The commander needs an estimate as to what it will take to cross this river. You need to also provide him with an estimated timeline for planning. • Unit: • One Heavy Brigade Combat Team (HBCT) • Task: • Cross a river as part of a movement to contact in designated sector • Conditions: • Augmented with two Improved Ribbon Bridge Companies (IRBC) • No helicopters allocated for this mission • Begin crossing at 2200 hours • Results of reconnaissance of the crossing site 2 1 EN Equip Park Holding Area Call FWD Call FWD Holding Area Staging Area Staging Area
Preparation of Site and RoutesCrossing Site 1 • This route requires horizontal engineer work at specific locations in order to widen it for tracked vehicles. • Additionally, there are locations where the grade slope is up to 25%, which impacts our wheeled vehicles (increased rollover rate, reduced loads in order to decrease weight) • Recommend reallocating horizontal engineers across the brigade as well as getting some heavier equipment (i.e. dozers, graders)
River Crossing Planning Factors(Crossing Site 1) 2 m/s 100m 180m 300m Entrance Slope Exit Slope Bank height Bank height Min depth of water Max depth of water
Establish Far Side Security Swimming / Rope Boat • Safe current velocity is less than 1.5 m/s for a swimmer to cross. • Based on assessed speed of 1.5 m/s and current tactical situation, don’t recommend sending anyone across by this means • The HBCT has assigned two combat Engineer Companies • 2x 3 man recon boats (use these to get the scouts over to recon the far side and set initial security) • Each IRBC has MTOE allocation of 30x Zodiac’s each but since this is a HBCT crossing they brought only 10 total to support this crossing • 2 are required as safety boats for the crossing sites, leaving 8 for the HBCT (4 per crossing site) Find out how many people need to cross as individuals vs traveling in a vehicle for each site. Then find out how long you’re allocated for this type of movement. If the answer is as long as you need modify the “Time Allocated” cell to figure out how much time you require. Consider tasking 1 boat per crossing site as a safety boat
Rafting Operations Rafting Operations (Crossing Site 1) The Brigade S3 has stated that he has to have at least a HBCT CAB Armor Company on the far side of the river before we can transition to building the ribbon bridge.
Ribbon Bridge OperationsCrossing Site 1 • Once the Armor Company is across the river all of the rafts are going to merge to build 1x Ribbon Bridge at crossing site 1. • The IRBC commander stated that his platoon for this site is his most experienced team • You’ve talked to the S3 about how the units are going to bring in their vehicles by march unit so that you don’t have a target rich location prior to the crossing • 25 vehicle per march unit, 2 minutes between march units