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SCUBAPRO SUNDAY – Buoyancy

Sunday, September 18th, 2022

Buoyancy is key to a lot of things when diving. It helps make the dive easier in a lot of ways. When using a closed-circuit rig (CCR), it keeps you from rocketing to the surface, and it prevents you from dropping to the bottom when you stop to fix your gear or “Dräger” talk/ yelling at your dive buddy.

The keys to buoyancy are balance and breathing.

The two significant factors in achieving neutral buoyancy.

Wear the right amount of weight for the dive. This will differ depending on the thickness of your wetsuit/ drysuit and gear you are wearing, also water type fresh or salt.

Breathing slowly and evenly, so you do not have too much air in your breathing bag. If diving a CCR

Steps to help maintain buoyancy.

Pre-dive preparation.

Buoyancy control begins with pre-dive preparation as you pick what to wear for a dive. Double-check to make sure nothing has changed that could affect buoyancy. A new wetsuit is more buoyant than an older one and will need more weight. A new suit has more inherent buoyancy at first because diving, especially deep diving, bursts the tiny bubbles in the suit over time. Make sure you look at any new gear compared to the old version. Equipment is constantly evolving and updated with new buckles or martial, so when you switch from old to new, make sure you know the buoyancy with the new stuff. Check the weights on a scale; often, there is variation between claimed and actual weight. If diving open circuit, remember cylinders are negatively buoyant when full and less negative when empty.

Do a buoyancy check.

Here is the best way to do a proper buoyancy check. With your lungs half-full, you should float at eye level with no air in your BCD. If you are diving open circuit, remember the average cylinder loses about 5 pounds as it empties. So, you might have to add about 5 pounds to your weight if you have done your buoyancy check with a full tank.

Keep a log

Keep a log of what gear you have worn, the temperature, and the type of water (salt/fresh /brackish). What equipment you used, how much lead you carried, your body weight, and whether you seemed too heavy or light. Knowing the weight of the gear that you used on the dive will help. Make sure you understand that if you are going to remove something during the dive, you need to account for that on the return trip home. If you plan by recording in training what you used, it will help when you have to do it the next time.

Saltwater VS Freshwater.

If most of your driving is done in the ocean, ballast calculations should be done for saltwater. Jumping in the pool to check your ballast will get you close, but it won’t be 100% correct. If you switch back and forth, you’ll need to adjust your ballast. Be prepared to add weight if needed sometimes, it’s nice to have a weight belt with extra pouches just in case, or maybe just an empty pouch on a gear belt will help. But still, try and keep the weight evenly distributed.

Buoyancy, Trim, Position, and Breathing

The secret to buoyancy control begins with fine-tuning your weighting. How much lead do you put into your pouches or have on your weight belt? If you carry just the right amount of weight, you will only have to put a little air in your BCD. That means less drag and more efficient finning. Less BC inflation also means minor buoyancy shift with depth, so you’ll have to make fewer adjustments. There are many tricks, but buoyancy control is a fundamental skill. Precise control of your buoyancy is what enables you to hover motionless and fin through the water at any depth. It would be best not to use your hands and not stir up mud or silt from the bottom by always moving your feet. In addition to using the right amount of weight, make sure you are correctly balanced to optimize your position underwater.

Keeping a more horizontal position makes you more hydrodynamic. Distribute the weight as uniformly as possible from side to side; you should never notice that you put more weight on one side while driving. It would help if you also considered the weight of your dive gear and any other additional gear you might be wearing. I.e., gun belt or special equipment. Make sure it is balanced on your body, and it doesn’t shift when you are diving. The lower you wear your dive rig can cause a tendency to push the diver forward (upside down) in the water, so the placement of weight towards the back can help reverse this position, especially on the surface. Make sure any dive weight you put on can be easily removed in an emergency.

Besides ballast weight, the factors that affect your buoyancy are BC inflation, your trim, exposure suit, depth, and breathing control. Your ballast weight and your trim are the only two factors that, once you’ve selected them, stay put. Ballast is the amount of weight it takes to keep you neutral in the water. Trim is about the position of your body weight relative to the position of your weight. Sometimes when diving a rebreather, you can tape lead washers on it to help with your trip.

There is one more thing to understand that will help with your buoyancy. It is controlling your breathing. Make sure you maintain proper breathing. Take relaxed breaths. This allows you to maintain control over your buoyancy.

To determine the amount of weight you need, you can take your body weight, the diving suit you will use, the weight of your equipment, and the environment you are diving in salt or freshwater. If you use about 10 percent of your body weight, that is a good starting point for a full 5 mm or more and for a 3 mm suit, use 5 percent of your body weight.

Drysuits and thick neoprene suits require more ballast to counteract the increased buoyancy of those suits compared to the thinnest. Body composition (the muscular density, for example) will also influence the necessary weight. Remember, fat floats, muscle sinks.

Remember to calculate everything you will use and wear on your dive if you are doing a long drive and plan to leave or remove something halfway thru your dive. Say conducting a ship attack, and you are taking limpets off. Plan for the whole dive, not just the start when you will be at your heaviest; plan if you are carrying something that you plan to leave behind, how will that affect your extraction. To check your buoyancy, get into the water deep enough to stay in an upright position without treading and releasing all air from the vest. Inhale, normally, the surface of the water must be at the level of your eyes. When you exhale, you should sink until the water covers your head and inhale again. You should emerge once again until the level of the eyes. Adjust your weight in small increments, about 1 pound at a time. You can use a weight with a snap link or just some weight with some 550 cord on it. Make sure you don’t just put all the weight you are adding to one side. Try and use this time to even yourself out and set your trim also. I have also seen people tap lead washers to the front of their rebreather to help even them out. The rule of thumb is never add more than 10Lbs. that can’t be released.

Once you get your ballast weight and trim dialed in, you will be ahead of about 75% of all divers toward perfect buoyancy control. Now you can fine-tune your BC inflation to compensate for the very predictable changes due to breathing down your tank and changing depth.

Lastly, there are advanced classes that you can take that focus on advanced skills like this. This may seem like a lot of work, but it will help make diving a lot better and make you more efficient at your job.

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SCUBAPRO Sunday – Combined Operations Assault Pilotage Parties

Sunday, September 4th, 2022

As I am sure you can tell, I love history. I find it amazing that even today, you can read something about WW2 that you never knew about. There were so many specialty units that sometimes it was hard to say, “Oh, this group gets its roots from…” Combined Operations is one of those groups, and they had so many smaller Units / Parties (I think I might have liked being part of “Parties” more than a Team. So, it would be “I am a party guy” and not “I am a Team guy”) that we are just now finding out about that they might not have been the father of some groups today. Still, they might have been the mother or the ugly step-sister.

While serving in the Second World War, Nigel Clogstoun-Willmott established the Combined Operations Assault Pilotage Parties (COPP), which were responsible for covert beach reconnaissance. This proved to be critical in the success of the Allied seaborne invasion campaign. Amphibious force attacks on land and sea are among the most dangerous of all military operations. Apart from the fact that they necessitate the precise coordination of armed forces on the ground, air, and sea, they might also be subjected to various issues associated with landing on foreign enemy beaches.

Among these are tidal roughness, inadequate sand and shingle texture, steep beach gradients, and restricted beach exits, for example. Various enemy defenses, including mines, beach obstructions, pill boxes, and gun emplacements, can make natural disasters more dangerous and challenging to overcome. Nigel Clogstoun-Willmott, an accomplished navigator in the Royal Navy, was one of the few who truly understood the gravity of the risks involved. He recognized that amphibious troops must be carefully directed into coastal waters by men who had been deployed to the coast ahead of the fleet.

Furthermore, he recognized that the only way to resolve these issues truly was to conduct a thorough reconnaissance of the proposed beach landing sites, work that would require men skilled in navigation, hydrography (marine surveying), and engineering to land covertly on the beaches at night.

Of all special forces operations, beach reconnaissance was one of the most clandestine and risky. The men engaged were forced to conduct their operations right under the noses of the enemy, knowing that if they were arrested and interrogated, their intelligence might jeopardize the entire operation and their lives.

In 1910, Clogstoun-Willmott was born in the Indian city of Shimla. A senior engineer, his father worked on significant infrastructure projects throughout northern India, including the construction of roads and bridges.

He was transported to England for his education, attending Lambroke School and Marlborough College until he was eight. He joined the Royal Navy when he was 17 years old, specializing in navigation and quickly earning a reputation as a creative problem solver and unique thinker.

The fact that he was aware of the dangers of landing on enemy shores came to him early in life. Gallipoli was the first sizeable amphibious operation of modern times, and his uncle ‘Cloggy’ had been severely wounded during the battle in 1915.

As a Beach Master for the landings at Narvik in the far north of the country, Clogstoun-Willmott received first-hand knowledge of these perils during the unsuccessful Norwegian campaign of 1940.

He was charming, courteous, and good-natured, but he was also a military professional who took his duties seriously. He spent a long time reflecting on the lessons learned from this campaign and how amphibious operations should be conducted going forward. In 1941, Clogstoun-Willmott was stationed in the Mediterranean with ‘Layforce,’ a commando group that had been dispatched to the Middle East. With the challenge of attacking the Italian-controlled island of Rhodes, Layforce got his first chance to put his theories into action.

As a result of his collaboration with Captain Roger Courtney, a canoeist who had recently created the Special Boat Section, which was primarily intended for marine reconnaissance operations, he could complete this task. Courtney and Clogstoun-Willmott worked together to conduct the world’s first in-depth military beach reconnaissance mission.

A wide variety of equipment was available, from flimsy cold-water suits made of heavily greased long johns and jumpers to the newest infrared signaling technology and the humble chinagraph pencil for taking notes in dripping wet conditions.

The mission was a resounding triumph. Both soldiers were honored, with Clogstoun-Willmott getting the Distinguished Service Order and Clogstoun receiving the Distinguished Service Medal. However, the valuable information gathered as a result of this work was never put to good use.

As a result of the British being lured into a futile attempt to resist the German invasion of Greece, the mission was called off entirely. Clougstoun-Wilmott was again called upon to serve as a Beach Master, coordinating British forces’ evacuation. His narrow escape from capture came after he commandeered a Greek caique and sailed it to Egypt, where he was one of the last to leave. Not until August 1942, following the failure of a massive raid on the French port of Dieppe, was it realized how essential Clogstoun-theories like Willmott’s were.

Admiral Louis Mountbatten, Director of Combined Operations, approached him and requested him to assemble a team – dubbed ‘Party Inhuman’ – to assist with Operation Torch, the invasion of French North Africa. He agreed and formed the team. When this endeavor proved successful, it resulted in the formation of the COPP in early 1943. The first order of business for the COPP was to conduct reconnaissance in preparation for the upcoming invasion of Sicily. However, due to insufficient training and equipment, achievement came at a high price this time. Only four of the sixteen guys who were assigned to the mission returned.

Later, Clougtoun-Wilmot, who is by nature a martinet and a training fanatic, collaborated with Mountbatten to guarantee that the COPP had access to the resources it needed to prepare for the invasion. The COPP teams were re-energized and contributed significantly to the Allied landings in Italy after re-energizing. During the D-Day landings, the COPP faced its most difficult challenge. COPP troops were now armed with tiny submarines known as X-craft, as well as specialty landing boats and diving gear, in preparation for the invasion of France.

They carried out a thorough study of the potential beaches and returned samples for analysis to establish that big trucks would be able to pass through them without being damaged. On D-Day itself, COPP personnel were dispatched ahead of the massive invasion fleet to ensure that it arrived safely. This scientific approach to warfare played an essential role in preparing for what was considered the most complex military operation in history.

While D-Day was the apex of the COPP’s operations, the unit also saw significant action in the Far East and the Mediterranean during its tenure. In 1945, it made it easier for people to cross the Rhine into the heart of Germany. Following World War II, the mission of the COPP was absorbed into what is now known as the contemporary Special Boat Service (SBS). They were beneficial during the amphibious operations during the Falklands War in 1982 due to their knowledge and expertise.

Later in life, Clogstoun-Willmott worked for the Navy in several positions and the intelligence agency MI5. At age 81, he passed away in Cyprus in 1992, after continuing to live an active life as a sailor until a few years before his death.

The COPP’s work was so closely guarded that it was not made public until after the Second World War had concluded. In the eyes of the public, Clogstoun-Willmott and his troops of the COPP continue to be unsung heroes of the Special Forces.

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SCUBAPRO Sunday – Low Volume Masks

Sunday, August 28th, 2022

Why is low-volume important to Combat divers? For anyone who needs to preserve their air while diving or wants a straightforward mask to clear, low-volume masks are the perfect option. These benefits are also great for freedivers and spearfishers. Low-volume masks are necessary for apneic (breath-hold) sports because relatively little air is required to equalize them at deep. The main reason is the air inside the mask will condense as pressure rises with depth.

This means there is less air wasted in the mask. There is also less of a chance of a mask squeeze. The mask is closer to the diver’s face, possibly helping you see better; the diver must equalize the air in the mask to make up for the volume lost if they want to avoid this. They accomplish this by slightly exhaling through their nostrils. Since there is less airspace in a low-volume dive mask, the diver doesn’t have to use as much of their precious breath on it.

Apnea masks are less noticeable and more streamlined than conventional masks due to their low-volume construction. They offer good fields of vision despite their size (sometimes even better than large-window masks!) and are lighter, and it is less weight and room needed to carry two.

Many divers hate mask clearing, and a low-volume mask uses less air to clear. When clearing, you are wasting less air and less chance of losing control of their buoyancy. Inverted teardrop-shaped lenses are standard in low-volume masks, allowing you to view down your body without moving your neck. This is a benefit for some divers because it makes it simpler to check their pressure gauge by simply looking down to see your attack board.

Low-volume masks are an excellent option for backups and spares due to their compact, lightweight design. They fit great into an M16 pouch.

Reducing the size of the glass lenses is one method of creating a low-volume mask. This doesn’t limit your vision as much as you think because the lenses are so close to your face. However, frameless masks are an excellent alternative for anyone who feels uncomfortable or claustrophobic wearing standard low-volume designs. Some apnea masks will say not for diving, those usually have two lenses like the SCUBAPRO Steel Pro Comp, and there is only a piece of rubber between the two. If you dive deep with it, there is a chance that the lens can push in on your face. Therefore they say not for SCUBA diving but for combat diver operations that work well.

The low profile is also suitable for those who want to wear corrective lenses, which function best when placed near your eyes (much like glasses). The SCUBAPRO Zoom and D-mask are an excellent choice for this. All these masks work with the SCUBAPRO comfort stapes that are great for all divers, especially combat divers, as there is a lot less chance of them breaking, and they also work with the SCUBAPRO Odin helmet mask strap. This allows you to attach these masks to Ops-Core, Team Wendy, and Galvion helmet rails.

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SCUBAPRO Sunday – Cramps When Diving

Sunday, August 21st, 2022

We’ve always been told that dehydration and accumulation of lactic acid were the driving causes of cramps. Sports drinks have made a ton of money selling us on that, but there is little scientific evidence to support these connections. For dehydration to be a driving factor, you’d probably be displaying clinical signs of dehydration; dizziness, tiredness, dry mouth, lips, and eyes. Instead, the cause of cramps may lie in the reflex nerves that control the muscle. Two sensory receptors are involved: muscle spindles and the Golgi tendon organ (GTO). The GTO senses changes in muscle tension. It lies in the tendonous area at the end of the muscle fiber. If the GTO is stimulated, it sends a reflex signal via the spine and causes the muscle to relax. The muscle spindle is embedded in the muscle itself. The reverse situation occurs if the muscle spindle is stimulated, and a muscle contraction occurs.

Cramp occurs when the reflex’s central nervous system (CNS) control is lost. The GTO becomes inhibited, and the muscle spindles become hyperactive. This leads to sustained activation of the muscle. If we follow this theory, then a muscle’s hyperexcitability is the basis of cramping; therefore, stretching should counteract the cramp. And guess what? We’ve known that for years. Stretches must be held for 15-30 seconds or until the muscles relax. After the cramp has gone, avoiding exercise for the next hour and applying heat will help. This allows the muscle and the CNS to recover.

So how do you avoid leg cramps in the first place?

Usually, you are told to maintain hydration and salt. But with some of the newer studies, that might not help as much as you think, at least for diving. It’s hard to do a controlled trial on yourself; hydrating one leg and not the other is impossible. Instead, we need to think about maintaining healthy reflex arcs. Poor flexibility caused by prolonged sitting, poor posture, or inefficient biomechanics will make it more likely that the reflex malfunctions.

Age is also a factor, and divers who haven’t ever experienced cramps may do so as you get older. Both aspects are increased body weight and eccentric muscle contraction (where the muscle lengthens as the load is greater than the force the muscle can produce). Many publications suggest that the diver’s choice of fins may be the biggest driver of cramps. Weak leg muscles need a smaller, thinner, flexible fin; athletic legs can drive wider, longer, stiffer blades. Fin manufacturers add several features to improve performance, ribs, channels, vents, and the material of the blade. I do believe that they help a lot also. I get a lot less cramps now that I use the SCUBAPRO Seawing Nova, Go Sports, and the New Seawing Supernovas. The SeaWing’s have rips in the fins to help not push on your feet as much when you kick. There are two types of Seawing Nova.

The Seawing Nova and the Seawing Nova Gorillas and there is now the new Seawing Supernovas. The Gorillas are a stiffer fin, and they are great for a working diver or someone in good shape. So, pick the right one for the job you are doing and the environment you will be in. I have been using the Supernovas and I love them, and I have not had any cramps. I am not saying it won’t happen but 6 months in and I am very happy with them.

Your footwear should not be too tight as this will restrict circulation and bone movement in your foot. With the new Supernovas you can adjust the tension on the heel strap. IT has three positions you can set it for. If you are diving in the winter and you add a dive sock to your booties to keep you warm, what you are doing is restricting your circulation, and that will make you cold and cause cramps. If you want to add layers have different sizes booties. The strap should not bite into the back of your heels too tightly, pushing on your Achilles tendon. This can happen if your footwear is too big and you are shoving your foot in and barely getting your strap around you heal or you are afraid you will lose your fin, so you pull the strap tight. Something that could help with this is a self- adjusting fin, like a bungee strap or a steel spring. This will help keep the right pressure on your heel.

However, it’s more likely that repetitive finning motions are driving CNS fatigue and loss of control of the reflex. If you feel cramps starting, change your position, change your fin stroke, and maybe try to float for a bit and allow the CNS to reset. I have used one leg to fin while stretching the other out and trying to keep up with my swim buddy more than once. The other thing that can help is wearing compression clothing. I have been using compression socks for long flights, long dives, workouts, and recovery for a while, making a huge difference. I did a 3-mile ocean swim a couple of months back and didn’t use the sock I usually wear, and I cramped up a lot. I am a massive fan of DFND USA clothing.

Cramping generally affects people that have taken a long break from finning. I say finning and not diving because you don’t have to dive to fin. So, like all your other skills, shooting, moving, and communicating. You need to practice finning, so you stay in finning shape. You should try and swim a couple of times a week. When you are in the pool, swimming with fins on will help strengthen all the smaller muscles. When you are at the gym, don’t just do arms. Do functional workouts that include a lot of exercises for your calves and strengthening the specific muscle groups that cramp when diving. Also try and include foot flexing exercises, as one of the other reasons for cramping is your feet are not used to being pointed for long periods of time,

They include toe raises, one-leg drop squats, and calf raises. Lastly stretch a lot. I am bad at doing it until my knees and body hurts and they I am like “why do I hurt? Oh, Yaa I need to stretch” I am a fan of Active Isolation Stretching (AIS). I carry 1in tubular nylon with me everywhere I travel, it lives in my bags. You can google it and you will find out how to do it. I have used it since BUDS to help with knee pain and it always does.

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Tulmar Receives Contract Extension

Thursday, August 18th, 2022

Tulmar Safety Systems is pleased to announce the extension of their Repair & Overhaul contract with the Canadian Department of National Defence for the Canadian Army’s Flotation Life Support Equipment. Pictured are Canadian Army Patrol Pathfinders equipped with Life Preserver – Underarm systems manufactured and maintained by Tulmar. Since its founding in 1992, Tulmar has become a leader in the field of tactical flotation systems. For more information on their capabilities and product suite, please contact military@tulmar.com

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SCUBAPRO Sunday – First Submarine Commando Raid

Sunday, August 14th, 2022

On August 17, the USS Nautilus and USS Argonaut were off the coast of Makin Atoll in the pacific. They were carrying 221 Marine Raiders. The Raider’s objectives were to destroy the Japanese garrison and installations, take prisons so they could be interrogated, and finally, the Gilbert Islands must be reconnoitered. It was also meant to divert Japanese attention and reinforcements from the Allied amphibious invasions on Guadalcanal and Tulagi.

Even with two 100-meter super-subs, A and B Company could only fit 221 men, so they left without a platoon from each. Maj. James Roosevelt, the president’s 35-year-old son, was one of Carlson’s targets. After serving as FDR’s political consultant and covert diplomat, the young Roosevelt joined the Marines. As a Raider enthusiast, he convinced his father to let him join.

Raiders were stuffed inside vacant torpedo tubes during travel. Submarine ventilation techniques couldn’t prevent thin air and high temperatures. The boats would surface for ten minutes twice a day to let the Raiders exercise and breathe fresh air before ducking back into the Pacific to avoid air assault.

The two submarines surfaced outside Makin’s coral reef at midnight on August 16–17 to find turbulent conditions. The first two LCRL rubber boats sank in the surf. The remaining launches’ uninsulated 6-horsepower engines were flooded with seawater and failed to ignite. Carlson felt his two-pronged approach would be too difficult to accomplish in the inclement weather and ordered A and B company to land together. In the chaos, the boat carrying Lt. Oscar Peatross and 11 Raiders missed the orders and headed west.

Carlson’s Raiders landed about 5 AM after battling the waves for an hour, with some troops scattered but undetected. Carlson’s invention was to divide his squad into three fireteams, each with one rifleman with a semi-automatic M1 Garand for distance shooting, another with a Thompson submachinegun for close-range firepower, and a Browning Automatic Rifle gunner to give covering fire. Heavy armaments included.30 caliber light machine guns and.55 caliber Boys anti-tank rifles were requisitioned from the Canadian Army by Carlson.

On landing, a Raider unintentionally fired his BAR, ruining any chance for surprise. The garrison’s commander, Chief Petty Officer Kyuzaburou Kanemitsu, had been alert days earlier. His men deployed by bike and truck to fight the American invaders. Misadventures continued when the Raiders kidnapped a Japanese soldier but shot him when he escaped.

Carlson met Makin locals who spoke pidgin English. They were pleased to help the Americans and said 160 to 300 Japanese were on the island, and they were ready. The Raiders maintained their march until 6 AM when Lt. Le Francois’ scouts sighted Japanese forces dismounting from vehicles.

Le Francois ambushed his platoon in a breadfruit grove on high ground. Sgt. Clyde Thomason adjusted the men’s positions as Japanese skirmishers neared. When the Japanese got close, the marines opened fire, killing the closest attackers and exploding the truck’s engine with an anti-tank rifle.

The Japanese answer was fatal. Four Type 92 Lewis machine guns raked Raider positions, killing Sgt. Thomason and injuring Le Francois. Posthumously, Thomason became the first enlisted Marine to win the Medal of Honor. Camouflaged shooters killed Lt. Jerry Holtom and four radio operators among palm palms.

Carlson quickly added the 2nd Platoon, which lost nine men in 15 minutes, and B Company. Raider machine gunner Cpl. Leon Chapman fired 400 rounds into a Japanese machine gun nest at 200 meters. After inspecting the silenced weapon, Chapman “nearly threw up” when he discovered he had slain a dozen Japanese who had sacrificed themselves to man it.

Twelve of Peatross’ forces landed at the second landing zone and proceeded uncontested into the barracks and the defender’s command position. An isolated squad shot six astonished Japanese before being held down by an LMG crew. Pvt. Vernon Castle was struck multiple times as he advanced, but he threw a grenade and killed three before dying.

After that, Peatross’ marines fired a car speeding towards the command post, blew up a radio and a truck full of ammo, and retreated to the Nautilus, losing two more troops. In the chaos, they killed Kanimetsu, who destroyed confidential documents and conveyed the message, “We are dying defending the island.”

The Nautilus began bombarding Japanese positions with two dozen shells when Carlson learned from natives that hostile ships were in the lagoon. Unwilling to risk a shore battery’s fire, the Nautilus arced 65 6-inch shells into the lagoon. By luck, indirect fire sank two ships, igniting a transport and a patrol boat and mistaking a hostile plane for a bird, the submarine dove, ending naval gunfire support. The Japanese assaulted the Raiders, attempting to swarm them failed, and the assailants were all killed at close range. Undeterred, the bugle played again, and the Japanese launched a second suicide strike, wiping out Kanimetsu’s marine platoon. A few dozen survivors continued to shoot intermittently. Fearing more reinforcements, Carlson chose not to strike the Japanese position. At 1:30, air support arrived. Twelve Mitsubishi F1M floatplanes bombed and strafed the island for an hour, driving the Raiders fleeing but not inflicting any fatalities. Then an F1M and a Kawanishi flying boat landed in the lagoon. The Raiders fired machine guns and anti-tank rifles at the aircraft, setting it on fire. The seaplane with scores of men managed to land. The intensity of incoming fire must have given the pilot second thoughts as he taxied on the water and took off again before landing.

The colonel decided to withdraw to submarines at 7 PM as planned. When they returned to the ocean, his troops discovered their boats’ motors had stopped working, and the waves and weather made it difficult to paddle back to the submarines. Exhausted Raiders dropped their ineffective launch motors and spent five hours trying to force through severe waves, losing most of their weapons and supplies. Eleven of 18 boats reached the American subs. By nightfall, Carlson, Roosevelt, and 70 injured Raiders remained on Butaritari. Individual boats continued to battle the waves the following day, including one with Roosevelt onboard. A five-person crew led by Sergeant Allard volunteered to row back to the atoll with a rope the Raiders could use to board the submarine. A squadron of Japanese jets bombed the Nautilus halfway through its launch. The subs crash-dove, and the jets strafed the rescue squad, killing them. After reassessing the situation, Carlson opted to finish the mission on Makin. The Raiders scavenged Japanese weapons to replace those washed away and sabotaged a derelict seaplane facility while avoiding air assaults. They burned much of the facility and 1,000 aviation fuel drums. Carlson decided his forces had a greater chance of reaching the submarines from the lagoon because it had no shore armament.

He encouraged the Nautilus’s captain to enter the lagoon using a semaphore lamp and a dinner chat they had earlier. The Raiders paddled on a raft of three launches, two working outboard engines, and local canoes as outriggers. The Indians gave them a canoe and buried their dead in exchange for USMC combat knives. The new boat reached the submarines, and the Raiders set sail for home. Among the 17 wounded soldiers, four surgeries were performed on the submarine’s mess table. The injured soldiers all survived.

On August 27, Carlson’s Raiders returned to Pearl Harbor to a hero’s welcome. They reported 18 dead and 12 MIAs and killed 160 enemies. According to Japanese records, 46 base personnel and an undisclosed number on Japanese boats and planes died.

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SCUBAPRO Sunday – Operation Magic

Sunday, August 7th, 2022

If you follow history, there is a lot said about how different battles were, this group took this hill, or this guy did this. But a lot needs to be said about what goes on behind the scenes. While the United States Army Signals Intelligence Section (SIS) and the Navy Communication Special Unit worked in tandem to monitor, intercept, decode, and translate Japanese messages during World War II, Operation Magic was the cryptonym used to refer to the United States’ efforts to break Japanese military and diplomatic codes. The Office of Strategic Services received the intelligence information acquired from the transmissions and forwarded it to military headquarters (OSS). It is widely acknowledged that the capacity to interpret and understand Japanese communications was a crucial component of the Allied triumph in the Pacific.

Early in 1939, the United States began its efforts to decipher Japanese diplomatic and military communications, even before the outbreak of World War II in Europe. In 1923, a United States Navy intelligence officer got a contraband copy of the Japanese Imperial Navy Secret Operating Code from World War I. Afterward, after all of the additive code keys had been discovered, the codebook was photographed and sent to the Research Desk, arranged in red folders by the cryptologists. The simple additive code was given the name “Red” in honor of the directories in which it was initially kept.

In 1930, the Japanese updated the Red code with Blue, a more sophisticated code for high-level communications. However, because the new code was too similar to its predecessor, cryptologists in the United States could fully decrypt the new code in less than two years after its introduction. At the onset of World War II, the Japanese were still using both Red and Blue color codes for various communications purposes. Listening stations were set up all across the Pacific by the United States military intelligence to monitor ship-to-ship, command-to-fleet, and land-based communications between ships.

The Japanese acquired encryption and security assistance from Nazi Germany after World War II erupted across Europe. Since 1935, the Germans have known that U.S. intelligence is monitoring and decoding Japanese communications, but they have not instantly informed the Japanese of this fact. Later, Germany delivered a modified version of its iconic Enigma encryption machine to Japan to assist the country in securing its communications. As a result of this, American intelligence was unable to understand Japanese intercepts. The tedious job of United States cryptologists was restarted.

Cryptanalysts in the United States gave the new code the moniker Purple. Purple, used to decrypt numerous variants of the original Enigma code, was the most severe obstacle to American and British intelligence throughout World War II.

After receiving information from Polish and Swedish cryptologists, the British military intelligence cryptanalysis unit at Bletchley Park became the first in the world to decrypt the German Enigma code in 1942. They then created advanced decoding bombes and the world’s first programmable computer to aid in the deciphering of the complex Enigma cipher. By 1943, British intelligence could use information obtained through translated Enigma intercepts received in near real-time.

For years, cryptologists in the United States sought to break the Purple code by hand. However, the format of Japanese signals, always opening with the exact introductory phrase, enabled code breakers to establish the sequencing of the multi-rotor Japanese cipher machine. By 1941, code breakers in the United States had made significant headway in cracking the Purple code, and they had gained the capacity to decipher multiple lines of intercepted messages. The procedure remained sluggish, and the information obtained from Purple was frequently outdated when translated into another language.

United States military intelligence became aware of British victories against Germany’s Enigma machine and requested that their allies share code-breaking information. Top Bletchley Park cryptographers and engineers were dispatched to the United States to assist in training code breakers and constructing decoding bombes. But they were highly protective of and didn’t want anyone to know about their Enigma code-breaking activities (codenamed Operation Ultra), which involved Colossus, the Bletchley Park decoding computer, and which they were involved.

United States intelligence made significant headway against Purple in a short period, thanks to the assistance of the British. A copy of the Japanese Purple machine, created in 1939 by American cryptologist William Friedman, was used to adapt a German Enigma bombe to decode Japanese Purple, which was then used to decode the Japanese Purple machine. Even though each message’s settings had to be determined by hand, United States intelligence improved its ability to read Japanese code with greater ease and timelier by 1942, six months after the Japanese bombing of Pearl Harbor and the United States’ entry into World War II.

With the help of their vast network of listening stations in the Pacific, the United States intelligence services could intercept and decode various other sorts of communications. In conjunction with JN-25 intercepts, the Diplomatic Purple transmissions, another broken Japanese Navy code, provided critical information to the United States military command about Japanese fortifications at Midway. The intercepts from Operation Magic provided valuable input during the ensuing Battle of Midway, which helped to turn the tide of the Pacific War in the allied forces’ favor and ultimately win the war. Approximately a year later, Purple intercepts provided the United States with intelligence about a diplomatic aircraft on which Japanese General Yamamoto, the mastermind behind the Pearl Harbor assault, was scheduled to travel. The Japanese aircraft were shot down by American planes.

Operation Magic was a vital source of intelligence information in both the Pacific and European theaters of conflict during World War II. Diplomatic messages between Berlin and Tokyo, encrypted with the Enigma and Purple codes, provided British and United States intelligence with information about German defenses in France during the Second World War. This information aided leaders in their preparations for the D-Day invasion of Normandy in June 1944.

The Japanese government remained uninformed despite the fact that the United States had broken the Purple code. According to the United States government, Japanese Imperial forces continued to employ the principles decrypted by Operation Magic throughout the war and in the weeks following the Japanese surrender in 1945.

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Marines Complete One of the Most Difficult Swim Qualifications the Marine Corps Offers

Wednesday, August 3rd, 2022

MCAS FUTENMA, Japan —

Thirteen U.S. Marines stationed across Okinawa graduated from the Water Survival Advanced course at Marine Corps Air Station Futenma on July 22.

WSA is the highest swim qualification that Marines can obtain before becoming Marine Corps Instructors of Water Survival. Throughout the course, students endured aquatic conditioning, endurance swimming, and underwater rescue training.

Taught by six Marine Corps Instructors of Water Survival, each Marine endured a physically demanding week of eight-hour training days in the water. The training included endurance swimming, underwater training, and rescue techniques.

“These students went through a lot of aquatic conditioning, underwater confidence training exercises, and team building exercises,” said Sgt. Bryantruc Nguyen, a network administrator with Marine Air Control Squadron 4, 1st Marine Aircraft Wing. “Underwater conditioning is extremely important, because it gives students a foundation before we transition them into making open water rescues. ”

Nguyen explained one of the most difficult parts for students was underwater conditioning. Events aimed toward underwater conditioning were usually conducted with only physical training shorts. The purpose of underwater training was to physically prepare students for tasks they would have to complete while making rescues.

“As MCIWS we make this course difficult so we can fully trust trainees to make rescues and supervise future swim qualifications.”

Sgt. Bryantruc Nguyen, 1st MAW network administrator

He said that the students completed two sessions of rifle-ups, a main component of underwater confidence training. During rifle-ups students would drop their rifles in the deep end. Once the rifles were at the bottom, they would dive down to retrieve their rifles and stay underwater until instructed to return to the surface. Instructors increased the time spent underwater after every succeeding repetition of rifle-ups. During this iteration of the course, underwater training forced a handful of students to exit the pool due to the difficulty of the task

“Students also struggled with Marine Corps rescues because they were forced to make open water rescues in their full combat utility uniform without panicking,” said Nguyen. “As MCIWS we make this course difficult so we can fully trust trainees to make rescues and supervise future swim qualifications.”

Per Marine Corps Order 1500.52D, the intention of swim qualification courses is to ensure that each Marine meets the expectation of being “amphibious by nature.” This requires Marines to be prepared if they ever need to make a rescue while on active duty.

“Swimming in combat utility uniforms was my weakness. I was a distance swimmer in high school, but I never swam in full gear,” said Lance Cpl. Tyge Watts, a motor vehicle operator with 3rd Transportation Battalion, 3rd Marine Logistics Group. “That’s a big obstacle you have to face, because it disrupts your form, and you have to go back and focus on the basics of swimming.”

In conjunction with underwater conditioning, students completed Marine Corps rescues and endurance swims. During the Marine Corps rescues, students underwent four different scenarios for rescuing a thrashing victim and properly escorting them out of the water in their full utility kit.

Watts explained that the 1500-meter swim and Marine Corps rescues in full uniform were the most difficult challenges for him. Everyday, students swam up to a mile, performed timed conditioning swims every day and focused on different swimming techniques that helped them maneuver comfortably in the water in their full kits.

Nguyen explained that this iteration of the WSA course saw 12 out of 21 students successfully graduate at the end of the course. The average dropout rate for each cycle is around 75 to 85 percent due to the intense physical demand to complete the course.

“WSA is definitely not a course for everyone, it’s a very big jump from the intermediate swim qualification course,” stated Nguyen. “It’s definitely a great course, but only a select few can say that they are advanced swim qualified.”

Marine Corps Installations Pacific

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