Module 1
Combat Diver Overview
Combat diving provides Special Forces with a clandestine maritime infiltration capability. Operating beneath the surface eliminates radar detection and visual observation, enabling SF teams to approach coastlines undetected. Combat diving is physically demanding and requires extensive training in SCUBA and closed-circuit systems.
Combat Diver Qualification Course (CDQC):
- Location: Naval Amphibious Base Coronado, CA (primary SF dive course)
- Duration: 6 weeks (for qualified military divers)
- Prerequisites: SF qualification, physical fitness standards, water confidence
- Attrition: Historically 30-50% due to physical demands and water competency
Mission Applications:
- Beach reconnaissance prior to amphibious operations
- Clandestine infiltration of denied coastal areas
- Underwater demolition of obstacles or targets
- Submarine lock-out and dry deck shelter operations
- Maritime interdiction and vessel boarding
- Exfiltration via submarine or surface craft
Physiological Considerations:
- Hypothermia: Water conducts heat 25x faster than air
- Barotrauma: Pressure injuries to ears, sinuses, lungs
- Decompression Sickness: Nitrogen bubbles from rapid ascent
- Oxygen Toxicity: CNS and pulmonary effects at depth
- Carbon Dioxide Retention: Rebreather-specific hazard
Environmental Factors:
Combat diving occurs in diverse environments: cold water, strong currents, limited visibility, surf zones, and contaminated water. Each environment presents unique hazards requiring specialized equipment and techniques.
Team Integration:
SF combat diving is typically conducted by the entire ODA or a designated dive team. Buddy pairs maintain contact throughout the dive. Team coordination underwater uses hand signals, light signals, and tactile communication. Surface coordination requires careful planning and timing.
Module 2
Open Circuit SCUBA
Open circuit SCUBA (Self-Contained Underwater Breathing Apparatus) is the foundation of combat diving. Exhaled gas is released into the water as bubbles, making open circuit less covert but simpler and more reliable than closed-circuit systems.
Combat Swim Systems:
- Draeger LAR-V: Standard military closed-circuit rebreather
- MK-25: Military open circuit SCUBA with twin tanks
- Swimmer Delivery Vehicle (SDV): Wet submersible for long-range infiltration
- Propulsion Vehicles (DPV): Increase speed and range; reduce diver fatigue
Basic SCUBA Equipment:
- Tanks: Aluminum or steel; twin configuration for redundancy
- Regulator: Delivers air on demand; first and second stages
- BC/BCD: Buoyancy compensator for depth control
- Weight System: Achieve neutral buoyancy; quick-release for emergency
- Fins: Long-blade for propulsion; Jet Fins standard for military
- Mask: Low-volume design; tempered glass; nose pocket for equalization
- Wetsuit/Drysuit: Thermal protection based on water temperature
Breathing Techniques:
- Slow, deep breaths optimize gas consumption
- Never hold breath — risk of lung overexpansion injury
- Breathe continuously during ascent and descent
- Monitor air supply; reserve air for emergency ascent
Buoyancy Control:
Neutral buoyancy is essential for efficient diving and bottom operations. Establish neutral buoyancy at the surface, then adjust for depth changes. The goal is to hover motionless without finning or using your hands. Proper weighting is critical — you should sink slowly with an empty BC and full exhale.
Equalization:
Pressure increases rapidly with depth. Equalize early and often during descent using the Valsalva maneuver (pinch nose, gently blow). Never force equalization. If unable to equalize, ascend slightly and try again. Ear squeeze can cause permanent damage.
Emergency Procedures:
- Out of Air: Share air using octopus or buddy breathe
- Free Flow: Switch to alternate air source; abort dive
- Entanglement: Stop, assess, use cutting tool if necessary
- Lost Buddy: Search 1 minute, then surface
- Decompression Illness: Surface, administer oxygen, evacuate to chamber
Module 3
Closed Circuit Diving
Closed-circuit rebreathers (CCRs) recirculate exhaled gas, removing CO2 and adding oxygen as needed. No bubbles are released, providing total acoustic and visual stealth. The Draeger LAR-V is the primary military closed-circuit system for SF operations.
Closed-Circuit Advantages:
- No bubbles — completely silent and covert
- Efficient gas use — oxygen consumed only, not wasted as exhaust
- Long duration — 2-4 hours depending on workload and depth
- Warmer breathing gas — reduces diver heat loss
- Reduced decompression obligation (pure oxygen at shallow depths)
LAR-V System Components:
- Breathing Bag: Counterlung that expands and contracts with breathing
- CO2 Scrubber: Soda lime canister removes carbon dioxide
- Oxygen Supply: Two oxygen bottles (primary and bailout)
- Automatic Diluent Valve: Adds gas to maintain loop volume
- Manual Override: Diver can manually add oxygen
- Bailout Valve: Open-circuit backup for emergencies
Operational Depth Limits:
- Maximum Depth: 20 feet (6 meters) for pure oxygen operation
- Oxygen Toxicity Risk: CNS oxygen toxicity increases with depth and exposure
- Operational Depth: Typically 0-15 feet for stealth approach
- Deep Bailout: Switch to open circuit if deeper operations required
Pre-Dive Procedures:
- Assemble and inspect all components
- Pack scrubber canister with fresh soda lime
- Fill oxygen bottles; check pressure
- Positive and negative pressure test the system
- Breathe on unit at surface to verify function
- Check bailout valve operation
In-Water Procedures:
- Descend slowly, monitoring oxygen supply and buoyancy
- Maintain constant depth to optimize scrubber efficiency
- Monitor breathing bag volume; add oxygen as needed
- Check gauges regularly (oxygen pressure, depth, time)
- Stay within buddy pair; maintain visual contact
CCR Hazards:
- Hypoxia: Insufficient oxygen causes unconsciousness without warning
- Hyperoxia: Too much oxygen causes CNS toxicity (convulsions)
- Hypercapnia: CO2 buildup from scrubber failure or skip breathing
- Flooding: Water in the loop contaminates scrubber and breathing gas
- Oxygen Fire: Rare but catastrophic; follow oxygen handling procedures
Bailout Procedures:
Any CCR malfunction underwater requires immediate bailout to open circuit. The bailout valve provides instantaneous switch to open circuit without removing the rebreather. Practice bailout until it is automatic — hesitation can be fatal.
Module 4
Underwater Navigation
Underwater navigation enables combat divers to reach objectives, maintain course, and return to extraction points without surfacing. Limited visibility, currents, and the three-dimensional environment make underwater navigation challenging and critical.
Navigation Methods:
- Natural Navigation: Use of terrain features, depth contours, and bottom composition
- Compass Navigation: Magnetic compass for heading maintenance
- Dead Reckoning: Heading + distance + time = estimated position
- Electronic Navigation: GPS (surface only) and acoustic positioning
- Transponder Navigation: Acoustic beacons for precise location
Underwater Compass Use:
- Mount compass on wrist or console for constant visibility
- Set bezel to desired heading; maintain needle alignment
- Compensate for current — crab angle to maintain track
- Check compass frequently; maintain situational awareness
Kick Cycles:
Distance estimation underwater relies on kick cycles:
- Measure your kick cycle distance on a measured course
- Typical: 1-2 meters per cycle depending on fins and technique
- Count cycles to estimate distance traveled
- Adjust for current (downcurrent = faster, upcurrent = slower)
Natural Navigation Features:
- Depth Contours: Follow constant depth to maintain course
- Bottom Composition: Sand, rock, vegetation patterns
- Sunlight Direction: General orientation if visibility permits
- Wave Surge: Indicates direction toward shore
- Current: Often parallel to shore; can aid navigation
Surf Zone Navigation:
The surf zone is the most challenging environment for combat diving:
- Chaotic water movement disorients divers
- Limited visibility from sand suspension
- Strong surge and undertow forces
- Approach perpendicular to shore in gaps between wave sets
- Use rip currents to assist exit; avoid swimming against them
Night Navigation:
- Reduced visibility requires greater reliance on compass
- Bioluminescence may provide some ambient light
- Close buddy contact essential
- Chem lights or markers for team coordination
- Light discipline — no white lights unless emergency
Navigation Planning:
Pre-dive navigation planning includes: compass headings for each leg, kick cycle estimates, time limits, turnaround points, and contingency routes. Plan for the worst visibility and strongest current — if you can navigate those conditions, normal conditions are manageable.
Module 5
Infiltration Methods
Combat diving infiltration uses multiple delivery methods depending on range, target location, and available assets. SF teams must be proficient in surface swimming, subsurface approaches, and vehicle-assisted infiltration.
Surface Swimming:
- Simplest method; requires only fins, mask, and breathing apparatus
- Range limited by diver endurance (typically 1-3 nautical miles)
- Stealth approach using darkness and sea state
- Combat Side Stroke (CSS) is standard military swimming technique
- Equipment carried in waterproof bags towed behind swimmer
Subsurface Swimming:
- Greater stealth; no surface signature
- SCUBA or closed-circuit rebreather required
- Navigation more challenging without surface references
- Equipment can be carried or towed on sleds
- Depth limited by equipment and mission requirements
Diver Propulsion Vehicles (DPVs):
- Electric scooters increase speed and range
- SF teams can cover 5-10+ nautical miles with DPVs
- Reduce diver fatigue and air consumption
- Navigation and communication protocols required
- Equipment and weapons secured to DPV
Swimmer Delivery Vehicle (SDV):
- Wet submersible carries 2-6 divers plus equipment
- Range 20+ nautical miles; depth 6-20 feet
- Operated from submarines or surface ships
- Divers exit and enter underwater at objective
- SEAL Delivery Vehicle (SDV) Teams provide Navy support to SF
Submarine Lock-Out:
- Submarines carry SF teams in Dry Deck Shelters (DDS)
- Divers enter flooded hangar; equalize pressure
- Exit through bottom hatch; surface or subsurface departure
- Return via same procedure in reverse
- Coordination with submarine crew critical
Surface Craft Delivery:
- Combat Rubber Raiding Craft (CRRC) — inflatable boats
- Rigid Hull Inflatable Boats (RHIB) — faster, longer range
- Mark V Special Operations Craft (SOC)
- Divers exit craft offshore; swim to objective
- Extraction at prearranged time and location
Beach Landing Site Selection:
- Suitable gradient for exit (not too steep or flat)
- Surf conditions permitting safe entry/exit
- Concealment for equipment cache
- Proximity to objective without excessive overland movement
- Defensibility if compromise occurs
Module 6
Maritime Operations
Combat diving is one component of broader maritime special operations. SF teams integrate diving with surface operations, vessel interdiction, and coastal reconnaissance. Understanding the full spectrum of maritime capabilities enhances operational effectiveness.
Beach Reconnaissance:
Combat divers conduct hydrographic reconnaissance to assess landing beaches:
- Beach gradient and composition (sand, rock, vegetation)
- Surf conditions and sea state
- Obstacles: natural and man-made
- Exit routes from beach to inland
- Enemy defenses and obstacles
- Hydrographic data: depths, currents, tides
Vessel Boarding Operations:
- Clandestine approach via underwater or surface swim
- Magnetic limpet mines for sabotage
- VBSS (Visit, Board, Search, Seizure) from surface craft
- Underwater hull inspection
- Harbor defense and counter-sabotage
Over-the-Beach (OTB) Operations:
OTB is the complete cycle of maritime infiltration:
- Launch from submarine, surface craft, or shore base
- Transit to objective (surface, subsurface, or combination)
- Surf zone passage and beach landing
- Equipment cache or carry inland
- Mission execution
- Return to beach; exfiltration by same or alternate method
Equipment Considerations:
- Waterproofing: weapons, ammunition, radios, documents
- Equipment bags: floatable, towable, camouflaged
- Immediate action gear: accessible while in water
- Concealment: camouflage face paint, dark clothing
- Survival: signaling devices, flotation if separated
Environmental Hazards:
- Marine Life: Sharks, jellyfish, venomous fish
- Water Quality: Contamination, pollution, temperature extremes
- Weather: Storms, lightning, sea state
- Navigation Hazards: Shipping traffic, fishing nets, underwater obstacles
- Tides and Currents: Can separate teams or drive off course
Joint Operations:
SF diving operations often integrate with Navy Special Warfare (SEALs), Navy EOD, and Marine Recon. Coordination includes: communications, navigation protocols, equipment compatibility, and command relationships. Understanding joint capabilities expands operational possibilities.
Training Maintenance:
Diving skills degrade without practice. SF dive teams must maintain proficiency through regular training dives, equipment drills, and refresher courses. Physical conditioning specific to diving (swimming, breath holding, cold water tolerance) requires constant attention.