24 October 2014

Driving a Boat into a Helicopter

Or:   Of Rubber Ducks, Double Ducks and Duck Recovery Ops

DUKW ("Duck")  Not this duck!
I've covered some aerial infiltration and exfiltration methods for land-based operations in the past two posts.  So, today, I thought we'd take a quick gander at some aerial INFIL/EXFIL ops that include water as a medium.

Zodiac Rubber Assault Boat with outboard motor.
Note the red fuel bladder. Everything on our boats
was black.          Photo courtesy: 
Kitairu Suppliers

I spent quite a bit of time on water operations teams, so I have quite a bit of experience with what the army calls Rubber Ducks, Double Ducks and Duck Recovery.

Now some of you may have seen the word Duck and thought of the vehicle in the photo at the top of the page: the GM-produced DUKW (pronounced "Duck") used by the US military during WWII. However, I'm writing about a different type of duck op.

The Rubber Duck

The Rubber Duck is an operation that parachutes team members onto a body of water (usually a sea, near a coastline) with a Zodiac Rubber Assault Boat.

Stack of standard pallets.  These may be
locked into the aircraft floor.
Since the pallet is going to be lost,
cheaper pallets --like this -- tend to
be used for ducks and double ducks.
It works like this: Team members strap a Zodiac to a pallet, which can be locked down on the aircraft floor.

The outboard motor is removed, and placed inside the boat, atop several layers of "crush material."

This crush material is usually composed of thick cardboard honeycomb, which is designed to expend the energy of airborne impact as it (the cardboard) collapses.  Thus, critical and sometimes fragile components of an operation (such as outboard engines for boats) are hopefully saved, arriving in usable condition after being tossed out the back of a plane moving at 125 knots, 1250 feet above the ocean.

How you push a pallet. (Zodiac pallet is shorter.)
One school of thought holds that it's okay to strap rucksacks down in the boat.  However, it's been my experience that this is a good way to lose equipment.  Consequently, my team nearly always jumped while wearing our rucks, loading them into the boat once we hit the water.

Once the boat is palletized, the team loads a C-130, C-141 or other similar aircraft with it.  And, once over the drop zone, they assist the aircraft Load Master in pushing the palletized Zodiac out the back ramp.
Don't think the load master is a coward, just because he's
strapped into the aircraft.

As the Zodiac's parachute deploys, the team chases the boat out the door, parachuting into the ocean behind it.  (Or, in front of it, depending on how you view things.)

This photo shows a different type of boat being parachuted.  However, it's probably about the same dimensions as a "Double Duck" which I'll get to in a minute.

If this were an SF Duck op, the team would be lined up on the right side of the ramp, waiting to run off.

After hitting the water, the team ditches parachutes, dons fins (and sometimes mask and snorkel) and swims to the boat.  This is why team members RUN off the ramp behind the boat: nobody wants to swim a mile and a half to reach the darn thing -- particularly in open ocean.

When preparing to jump, team members hold the fins together, usually under the left arm.  The fins are held firmly in the left hand (which also grasps the left side of the reserve chute in a standard jump), with the ankle straps wrapped around the left wrist.  The fins are also often "dummy corded" (tied) to the jumper's equipment.

Mask and snorkel may be carried in buttoned pockets, or lashed firmly to gear, or taped down with "100-mile-an-hour tape" (military duct tape, which is Olive Drab on the outside, instead of gray). Rifles are loaded with one magazine, then wrapped in two plastic garbage bags (see-through kind), leaving some extra air inside to provide assistance in firing from the bag, if necessary.  Weapons are slung upside down and dummy corded to the jumper.  Sidearms are placed in large plastic baggies, then holstered securely. [Some teams like to strap weapons and load-bearing vests (LBE) to the rucksacks, but I always worry about losing my ruck.  Hence I tended to wear my LBE and weapon.  After all, my LBE had canteens of fresh water, pen flares, and other important survival equipment.]

Our local scuba team liked to jump wearing their gear over T-shirts and UDT shorts, or else in wet suits. Most of the time, however, my team jumped in full uniforms, knowing we'd need to wear them when we hit shore. (Conducting a surprise fire-fight in shorts and a T-shirt would not be fun imho.  The SCUBA Team, of course, expected to wear SCUBA gear into the shore landing, so they looked at things differently, expecting to change into uniforms after landing.)

Rucksacks hang off the jumpers' fronts, clipped on with two clips, just below the reserve parachutes. Each jumper carries a 20 to 30 foot length of 1-inch nylon tubing (or a rope) snap-linked to his equipment harness.  The other end is snap-linked to the frame of his rucksack, in which all equipment has been sealed in large plastic trash bags with most of the air removed.  The nylon tubing or rope is S-coiled into a cargo pocket on the jumper's hip, or into a side pocket on the ruck, for ease of deployment when needed.

On the way down, jumpers try to "slip" their parachute, or drive their "steerable canopy" parachute, in the direction of the boat, to cut down on how much time it takes to put the boat into action and move out.

Upon hitting the water, jumpers remove their parachute harnesses, letting the chutes sink.  They swim a short distance away to avoid becoming entangled in parachute lines as this happens.  Then, they get their fins loose and put them on.  Fins NEVER go on bare feet.  (I had scars for over ten years, because I repeatedly swam with fins on bare feet in pre-scuba school, because booties were unavailable to me.)

Jungle Boots
Dive Booties
Fins may be worn over booties, or military boots.  However, standard combat boots are designed to prevent excessive ankle movement and, in my experience, consequently inhibit efficient swimming with fins.  Wearing booties tends to solve this problem, but booties provide limited foot protection when landing on coral, or when conducting initial patrols inland to secure the beach.  I have found that regular issue jungle boots tend to provide all the ankle movement I need for swimming with fins on, and they permit me to cross beach, hinterland, or even coral with no problems.  Just be sure to wear socks!

After donning fins, etc. the swimmer (who used to be a "jumper" but it no longer jumping -- that part's over) pays out the nylon tubing or rope, that's S-rolled in one pocket, and starts swimming for the boat, towing his rucksack behind.  If properly prepared, the air trapped in the trash bag, inside the ruck, will provide slight positive buoyancy, keeping it barely afloat.

Upon reaching the boat, team members unstrap the boat from the pallet and let the pallet sink.  They then remove the snap-link that holds the nylon tubing, from their gear, and clip their ruck rope or nylon tube to the boat. After the ruck is secured, and still floating, they climb aboard and remove the parachutes, letting them sink.  After this, the motor is cut loose and fastened to the transom -- the (about two inches thick) wooden board that makes up the boat's stern.

This boat design is different,
but you can see the engine plate quite well.
The transom has a metal plate on it, called an engine plate, because this is where you fasten the engine.  The outboard is held by what are essentially two permanently installed, large C-clamps, which you screw tight to the engine plate on the transom.  It usually takes two guys to do this, if you don't want to lose the engine overboard in high seas.  And, engines are heavy, made of metal, and sink fast!  So, you have to be careful not to drop it, or all those folks who USED to be your friends, are going to be helping you paddle miles into shore. (Some far-thinking team members dummy cord the engine to the boat, until everything is clamped firmly, just for this reason!  It's still a pain to haul the engine back up, and get it going, but it sure beats the alternative.)

The fuel bladder is then hooked up, using the clip valve on the end of the long, thin rubber tube that connects the bladder to the engine.  If you're smart, you lash down the bladder so you won't lose it in high seas.  Rucksacks are pulled in and loaded aboard, and everyone gets situated.  Then the engine is fired up -- and you're off!

All of this stuff is best conducted at night, of course, to prevent prying eyes from watching your movements -- which throws a very special monkey wrench into everything: including finding the boat and getting it ready to go.

For this reason, red chemical lights are usually attached to the boat when it is palletized, and "cracked" (turned on) just before pushing it out the door.  The first person to find the boat usually climbs on top and waves a red chem light as high as he can, to assist others in finding the boat at night, in high seas.  Red is chosen because this color is a bit tougher to see.  Make of this what you choose.

Once the boat is "up" and everyone is situated, the coxswain drives the boat across the ocean, aiming to land at a desired location.  Navigation may be based on lights seen ashore, GPS equipment, magnetic compass and chart references, nautical navigation tools (such as tide charts and whiz wheels), or a combination of any or all of the aforementioned.

Scout-swimmers seldom wear rucks.
While, technically, you can take an M-16
and fire it almost as soon as you take it out
of the water, you may have problems if
water is still in the barrel.  This is why we
trash-bagged our weapons, leaving room
for air and expended rounds in the bags.
At a few hundred meters from shore, two scout-swimmers are put into the water.  These are usually the team's best swimmers, and they'll swim into the landing site, ensure no enemy are present, then conduct a reconnaissance before taking up security positions over-watching each end of the beachhead, and signalling the boat to come in (usually by flashing a pre-arranged Morse letter signal, using a red-lens flashlight).

How the boats come in: HOT!
Once the signal is received, the coxswain cranks the throttle and drives the boat hell-for-leather into the beach, trying to make it climb the sand as high as possible.  Coral is highly destructive to a rubber boat, so it is avoided if possible.  If the boat must land on coral, this will be made clear with a signal from the scout-swimmers, and the coxswain will slow as he approaches the beachhead to minimize damage.

After the boat is beached, the team will carry it inland, often deflate it, then try to hide it: burrying it, and/or camouflaging its location.  The boat location will be marked in the standard manner used to note cache sites.

Double Ducks

Double Ducks are run just like Rubber Ducks, but two boats are used.

The reason for this is simple: One Zodiac fits about half an A-Team, with their gear.  Any more, and it gets overloaded, which causes problems.  So, the team jumps in with two Zodiacs, instead of one.

When palletizing, the two Zodiacs are stacked on top of each other on the pallet.  Everything is strapped and lashed together, to form one cohesive package for the drop.  And, once everybody's in the water, the boats are pushed apart and each team works on its own boat, readying it for the run in.
A Double Duck makes landfall.

Duck Recovery

Duck Recovery Operations vary, depending on the vehicle being used to recover the boat(s) and/or swimmers.  And it's a place where the SF mantra of "That's wild, and undoubtedly quite dangerous, but we can do it," becomes something more like: "You've gotta be kidding me!"

I've spoken to SCUBA team guys who waxed long about the exciting experience of having a submarine surface with the conning tower just astern of the long ropes holding the team's two Zodiacs together.  The sub kept moving slowly forward as it surfaced.  When the conning tower caught up to the ropes, it caught them, and the two boats were swept back over the rear deck area of the sub.  As the sub came farther out of the water, team members used paddles to keep the boats from being swept over the side, and were later able to step from their boats onto the (relatively) dry deck, deflate their boats, and go below.

I've never done that one, but I have driven a Zodiac into a helicopter several times, and been on board Zodiacs driven into helicopters several more times.

(At left is the photo of a model of a CH-47 Chinook.  Though it's a model, I think it gives you the best look at the overall bird.)

The secret here is that the CH-47 Chinook helicopter does NOT float . . . but it does sink slowly.

Special Operations puts this fact to use, by letting a Chinook "land" in a body of fairly flat, calm water.  This doesn't work very well in open ocean, but can be done in inland waterways, on lakes, or in coves, etc. where the waves don't get too tall.

The pilot puts his rear ramp down, when landing, and keeps the rotors running (there are two rotors, fore and aft: see photo).  This provides lift, increasing the helicopter's "float" time.  Meanwhile, the team on the Zodiac drives as fast as they can get that little rubber boat to go -- right up the ramp and into the back.  The chopper's got about six inches to a foot of water in it, by this time, so the boat has water to run across as it comes in.  Just before entering the ramp area (Remember: the ramp is down, and lying under the water starting about five or six feet back from the open rear of the chopper!) the coxswain cuts the engine as his assistant unlocks the engine, permitting them to hinge it up and forward, lifting the prop out of the water.  The boat continues to coast, but team members rapidly grab the wide nylon webbing of the troop seats that have been folded up against the interior sides of the helicopter.  Team members continue to grasp this netting -- hanging on for dear life! -- as the pilot lifts off, moving forward, and all that water spills out, running in a river right out the back of the open ramp.  As the water runs out, the boat settles.  Eventually, the ramp is brought up and locked closed, at which point the team can let go and stand up, getting out of the boat.

At this point, the Zodiac may be deflated and the troop seats may be lowered so team members can sit in them for the flight back to wherever they're going (usually an intermediate staging area, where they leave the CH-47 and board a large jet transport like a C-141 to make the long flight home).

In my experience, however, since this recovery operation usually comes at the end of a long, exhausting deployment, team members often opt to keep the boat inflated, then flop in,on and around it to fall deeply asleep until the chopper lands.  If the Crew Chief, Pilot or Load Master decide to deflate the boat, however: it gets deflated.  Anyone who complains is usually invited to walk or swim home.

Oh, one other thought: this is also usually done at night.  And the coxswain is usually equipped with goggles to help him deal with the sea spray kicked up by the Chinook.  Unfortunately, not only is it dark.  Not only is the chopper marked with dim chem lights.  But, also: those goggles are usually pitted and scarred to near un-usability.  Consequently, finding that chopper can be tough.

Once, in training, it took me so long, as coxswain, that when we finally got to the penultimate moment, my Team Sergeant suddenly lunged back at me, knocking me to the floor of the boat, just as we shot under the open ramp of the rising chopper, gallons of water dumping on us and swamping the boat.  The Chinook pilot had decided he either had to fly, or sink!  So he chose to fly, of course.  I hadn't been able to see through the dark night, sea spray and awful goggles.  The pilot came back, though, and we did it again -- successfully this time.

That's it for now.  See you in two weeks!


  1. One other thought about that photo of the scout-swimmer: He's got his fins snap-linked to his belt or equipment (LBE). I usually preferred to run my upper left arm between the the fins and their ankle/heel straps, letting them dangle from my off-hand arm when emerging with my weapon. My thinking was this might give me a better chance to get them on fast and haul a#* if somebody started shooting at me. I got this idea from our local SCUBA team members, who practiced it. And, it worked well for me when I tried it. Would it have really made a difference if I was taking incoming rounds? Thankfully, I don't know the answer to that one.

  2. Your ever so useful pieces make me wish I wrote action thrillers!

  3. Thanks, Janice. My hope is somebody who does write action thrillers might think this useful. We'll see . . .

    I hope you found it interesting. Of course, this is really what was done in the 1980's and 90's, so a lot may have changed -- including the boats used. Looks like the SEAL's, at least, might prefer rigid boats these days, which the Chinook picks up via "sling load" carrying it so that it hangs beneath the chopper in flight.


  4. Dix, great article. I could follow the detailed descriptions all the way through. Nice photos too.
    Question: how does leaving extra air inside the bag provide assistance to the rifle if you have to shoot it while it's still in the bag?

  5. Excellent question, R.T.:

    It's my understanding that the military issue rounds we used were sealed tightly enough (slug seated into shell casing, that is) to be water tight. And that each round contained enough on-board oxygen for firing. So, technically, you could submerge the weapon for a fairly extended period of time, and still "keep your powder dry." But, the powder inside the shell casing is an explosive, and as I've written in my explosives posts: sometimes things go wrong with explosives.

    We bagged the weapons, firstly, to keep water away from the mechanism of the weapon itself -- the moving parts, which required greasing or oiling to function properly. Salt water could rapidly corrode some of these elements, while the salt itself, or other items (such as sand or silt) floating in the water could get caught in the mechanism and cause a weapon to jam.

    We left the extra bulge of air to ensure our bullets had enough oxygen to fire, in case something was wrong with the mix in the casing, or that the casing leaked for some reason. This bulge also gave us room to grab the pistol grip of the M-16 through the bag, and pull the trigger without removing it from the bag (which would be torn and sometimes burned by firing). This bulge also provided enough room to catch spent rounds as they were ejected. The idea here, was to be sure a scout-swimmer had a properly functioning weapon, the instant he poked head and shoulders (and weapon) up out of the surf at the beach.

  6. Great scott! I was hyperventilating by the time you got to the part where they drive the boat right up into the back of the helicopter! Lord have mercy! It's a darned good thing I never tried to do any of this! LOL ("The good news is we made it. The bad news is we lost the fat old lady at the point where everybody jumped out over the ocean with 300 pounds of gear, a boat, and a boat engine. But if you listen, you can hear her still screaming somewhere up there...")

  7. And here I always thought ‘duck’ meant get your head the hell down and double-duck was to get your butt out of the way, too. Damn, Dixon, I think I was once a big, active guy, but now I feel like Pee-Wee Herman instead of Pee-Wee Harris.

    No, seriously, I love this stuff. It’s wonderful. Thanks.

    Now I'm going to do some duck recover with ice cubes.

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