How Effective Were Depth Charges Against Uboats?

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As depth charges were deployed, submarine commanders were able to estimate the range and approximate direction of a Uboat. The charge also caused a secondary shock wave that was weaker than the initial shock wave but lasted longer. This caused the hull to breach, which killed Uboat crews.

Hedgehog depth charge

In the Second World War, the Royal Navy developed the Hedgehog, a forward-throwing anti-submarine weapon. It was a multi-spigot mortar that fired ahead of a warship attacking a Uboat. It was also used to augment depth charges.

While the British initially used the Hedgehog, the USN later adopted the technology. The USN version was more robust and versatile than the British, and had a target designation transmitter. This gave USN crews greater control than conventional depth charges. This innovation proved to be a significant advantage in the war.

The Hedgehog depth charge was first deployed in the Pacific during World War II. The US Navy and the UK produced over six hundred and twenty-two depth charges. These included the Hedgehog and the Mousetrap. They were also equipped with asdic and radar. These weapons were capable of hitting a variety of targets.

Before using depth charges, a submarine must reach a minimum depth. This range is based on the estimated depth at which the submarine is operating. A depth charge can cause the submarine to move quite a distance, so the conning officer must estimate this distance and account for this in order to place the barrage at the proper depth. The two-part timing of the Hedgehog depth charge against Uboats is illustrated in Figure 5. The elapsed time between the loss of contact with the submarine and the explosion of the depth charges is about 50 seconds.

Long-range DC thrower

Long-range DC throwers were developed during World War II to combat Uboats. These weapons used standard Mark VII depth charges and were able to reach a range of about 330 yards. They required a nine-minute launch time. They could be used by a variety of ships, including submarines.

These weapons were often disposed of in small groups along a convoy’s course, and were placed one run apart. Consequently, each U-boat could only attack a convoy once a night. Moreover, they could not find the convoy because they were hampered by bad weather.

Secondary shock wave

Depth charges were used in World War II to destroy Uboats. They were a lightweight explosive device that could cause the submarine to become unstable. They also posed danger to the crew and equipment aboard. They could only be used in close proximity to the target and rarely hit the target. Even if they did, most of the Uboats destroyed by depth charges were sunk by the damage accumulated over an extended barrage.

Deep-diving German U-boats were designed to be destroyed by depth charges. However, these devices were never used in the Far East. However, this did not mean that they were useless. They were a great tool for flushing diesel submarines. The first depth charge that entered service in the United States was the Mark 9. It weighed 200 pounds and had a depth setting of 600 feet. Later versions of this weapon reached higher depths and were faster, reaching a speed of 22.7 feet per second or 6.9 m/s.

The first depth charge was created in the United Kingdom in 1914. After several tests, the British Navy endorsed it as a weapon against submarines. The device consisted of a barrel-shaped hull that was filled with explosive. The depth charge was dropped from a ship into the enemy submarine and detonated by water pressure.

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However, these depth charges were not very effective. They continued to expand and contract for a few minutes. This meant that depth charges were used sparingly during the war. However, the Q-ship Farnborough was able to sink a U-68 off Kerry, Ireland, on 22 March 1916. The news of this sinking quickly reached RAF Coastal Command and a depth charge was developed to be used from an aerial position.

Causing catastrophic hull breach

One method of causing a catastrophic hull breach is by firing depth charges against an Uboat. Unlike traditional gunfire, depth charges can only cause damage to submarines that are about five or ten meters deep. Moreover, the more distant the Uboat is from the target, the greater the damage the depth charge can do. In addition, depth charges can also cause a pressure spike.

The initial development of depth charges was for aerial use, but their use in shallow water remains popular today, especially for flushing prey. However, these weapons must be calibrated to the correct depth and deployed accurately. The attacker must lay a pattern of depth charges over the suspected position of a submarine. This way, he can engage the submarine while it is at a stand-off distance.

The shock wave produced by a depth charge is very strong, and it can cause damage to both personnel and equipment aboard the vessel. The secondary shock wave, which occurs when the gas bubble expands and contracts, also causes damage to the vessel. In some tests, up to 16 cycles of the secondary shock wave were recorded.

In 1914, the first depth charges were invented in the UK. After successful testing, the British Navy adopted the new weapon. However, the first depth charges were not effective weapons against submarines. The depth charges consisted of a barrel-shaped hull stuffed with explosive. The depth charges were then dropped from a ship onto the enemy submarine and detonated by the water pressure.

In the attack on U-123, the Norwegian tanker Kosmos II was also chasing the U-123. The crew members of the Kosmos II were trying to ram the U-123 with their stern torpedo. It was a massive ship, with 16,966 tons. But Hardegen’s engineers patched the starboard engine, gaining an advantage of one knot over the Kosmos II.

Effects on personnel and equipment

The effects of depth charges against Uboat personnel and equipment depend on the ship and the attack strategy. A 750-pound depth charge will take 40 seconds to sink, but an eight-knot submarine can change its depth by 60 feet within this time. However, a submarine that is stationary does not stand a chance against a depth charge.

Submarines must maintain a constant lookout to see if they are being attacked by aircraft. Once they detect the aircraft, they must determine whether to dive, remain on the surface, or retreat. While they can always retreat, the likelihood of success is greatly decreased.

In the case of the U-85, the US destroyer USS Roper was able to detect the enemy warships using radar, and then sank the U-boat. The U-boats sank 17 ships from the convoy. They also intercepted two other convoys and sank another twenty-one ships. They did not lose any of their torpedoes during this attack, but they were forced to return home for reloading.

During World War II, the U-boats posed a major threat to the Allied Fleet, and the Japanese military took advantage of their lack of firepower. However, there are many ways in which depth charges can affect the U-boats. One of these is by destroying their crew and equipment. Those who want to defend their country against submarines need to understand how depth charges work.

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The effect of depth charges against Uboat personnel and equipment depends on the type of weapon used and the nature of the attack. Submarines are often deployed in small groups and have limited time to remain in one location. The length of the attack depends on the commander’s ability to control his unit and the efficiency of the crew.

Old ships did not rot from seawater because they had a unique anti-fouling coating made of copper. It was a relatively costly anti-fouling coating, but it prevented rot in a variety of ways, including on wooden boats.

End grain sealer kit

If you are interested in keeping your ship or boat free from seawater rot, then an end grain sealer kit is an excellent choice. A water-based or solvent-based polyurethane sealer can be applied to the wood surface with ease. However, there are some disadvantages to this type of sealer. The first disadvantage is that it may raise the grain of softer woods. Another disadvantage is that it can take several days to fully dry.

Another disadvantage of using this product is that it is expensive. A cheaper product will only last you a few years, but a premium one will last for six to ten years. This is much longer than most wood sealers, which require reapplication every three or four years.

Secondly, it will prevent wood rot by making it waterproof. The MARINE Premium wood sealer is specially formulated for wood structures in close proximity to water. Applying two or more coats of this sealant is recommended to achieve the best results. This type of sealant will create a rubbery seal and stop the water from penetrating into the wood. The sealant will also extend the useful life of the wooden boat or ship by preventing impurities from settling between the wooden boards.

The CPES(tm) treatment can also be used to treat areas that do not have obvious rot. CPES ™ is an adhesive sealant that can be used in a variety of applications, including wood and plywood.

Composite hulls

Composite construction uses a combination of materials for the hull of a vessel. Early composites included a timber carvel skin, an iron frame, and deck beams. Wooden hulls could also be protected with sheet copper, which prevented marine fouling. Copper bottoms were also used on fast cargo ships to prevent seawater corrosion. Modern composite hulls can be made of GRP or ferrocement. The term composite is also used to describe plastics reinforced with fibers other than glass.

Composite hulls made of wood did not suffer from rot when immersed in seawater. This is because the timbers are protected from oxygen, which is needed for the process of decay. However, wood in freshwater can rot. So, the comparison between wooden and composite hulls is misleading. Moreover, wooden boats usually need to be protected from seawater through a gel coat, which can be applied to the hull surface.

While thermally modified wood can protect timber structures in seawater, such treatments will only provide protection for a short time. Alternatively, physical barriers can protect timber structures from rot in the presence of seawater, but their effect will be limited. Physical barriers, like geotextiles, can be applied to timber structures, but they can be limited by cracking, breaking, and corrosion.

Tar or pitch

Pine tar is a dark color produced from the destructive distillation of pine wood, and is diluted with turpentine to reach the desired viscosity. This tar is also known as «peasant-made tar» because of its high resin content and low pitch content.

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Old-growth lumber is very dense and has absorbed minerals from the soil over many decades or centuries. It is also more resistant to rot, unlike modern trees. A ship or boat made of wood that is exposed to saltwater for extended periods of time may rot.

A boat made of cedar is naturally resistant to wood rot. It is a great example of how wood can be treated. Tar or pitch is a protective coating that prevents wood from rotting from seawater. Once it has dried, it can be glued or finished. However, it is important to be aware of the dangers associated with using these chemicals and bacteria. Make sure that you have an adequate ventilation system before beginning work. Additionally, you should wear protective masks to protect your respiratory system from vapors from the chemicals.

In addition to being a waterproofing material, tar or pitch was also used to make ships and boats made of wood water-tight. It also protected ropes from deterioration. Tar or pitch is a viscous dark brown liquid that is extracted from various organic materials. Wood burning to produce charcoal is another common source of tar, and coal tar is a byproduct of coal gas and coke production. It is subsequently refined into pitch. Tar is used in many applications, including construction materials and paint.


Caulking is essential to prevent seawater from penetrating the hull and other parts of a boat, especially wooden vessels. In the past, it was common for wooden vessels to leak water, but it wasn’t a big deal. Today, however, bilge pumps are required for all wooden vessels. In addition to bilge pumps, a boat should also have a good coppering. Coppering helps keep the caulking in place.

Wooden ships and boats have historically been built with plank-over-plywood hulls. This technique results in little or no water seeping into the bilge. Over the years, the process was refined and gained widespread acceptance. Today, cedar, teak, white oak, and other long-lasting woods are ideal for boat hulls.

In addition to providing moisture barrier, caulking prevents rot and damage caused by moisture. Wood does not readily absorb moisture across its grain when it is whole, but once it is cut into planks, it begins to lose its ability to absorb moisture. When the moisture is allowed to penetrate further, it will cause further rot. Most rots are caused by fungi that need moisture to survive. Therefore, caulking helps prevent rot by filling gaps between planks.

While there are many types of caulking, the most important is the zinc-based one, which prevents water from penetrating the hull and other parts of the boat. This method is the most effective and efficient method to protect boats from seawater.


Preservatives were used in ancient times to protect wooden ships and boats from seawater deterioration. Over time, a variety of treatments were developed to ensure that ships and boats of all types and ages would not rot in seawater. Some of these treatments included tarring or pitching old timbers, which was done to keep them dry and safe from rot.

One of the most common wood preservatives is DCOIT. This water-based product is approved for pressure treatments and sapstain protection, as well as millwork and lumber applications. It was approved for use in utility poles in 2018. Another type is OIT. This is a triazole that is registered by the Environmental Protection Agency (EPA).

Other preservatives include ACQ, MIT, and CMIT. These products are registered with the EPA and are safer than older versions. However, some of them may pose health risks for people. These preservatives should be used with caution and only in places where they are needed.

Borate preservatives have been used for large and small repair projects. The products come in different formulations, but the most common form is a water-based solution that is applied with a brush or roller. Plastic sheeting is also commonly used to apply the product. Boron solutions can be applied to even the largest timbers.

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