HMS Jersey, Malta

On 25 March 1937, the British Admiralty placed orders for the eight destroyers of the J class, including one ship. Jersey was laid down on 20 September 1937 and launched on 26 September 1938.Jersey was commissioned on 28 April 1939.

 She was kitted up and ready for war.
2 × Admiralty 3-drum boilers

Propulsion: 2 × shafts; 2 × geared steam turbines

Speed: 36 knots (67 km/h; 41 mph)

Range: 5,500 nmi (6,300 mi) at 15 knots (17 mph)

Armament:  3 × twin QF 4.7-inch (120 mm) Mk XII guns, 1 × quadruple QF 2-pounder (40 mm) anti-aircraft guns,2 × quadruple QF 0.5-inch (12.7 mm) Mk III anti-aircraft machineguns, 2 × quintuple 21-inch (533 mm) torpedo tubes, 20 × depth charges, 1 × rack, 2 × throwers

She was ready in April 1939 and she set sail for war in Sept, along wih HMS Jervis to intercept navy in Norway, and was involved in several campaigns till she was hit by mine on 6th Dec 1939 and was then under repair till Oct 1940. When she return to active duty she was then sent on a British raid on Genova Italy, 6 feb 1941, with battle group of ships,Battlecruiser HMS Renown, Battleship HMS Malaya,Aircraft carrier HMS Ark Royal & 6 Destroyers left from Gibraltar, and head over to italy to cause menace on Genova, Livorno  and la Spesia and lay mines and engage any enemy encountered, Fleet returned safe on the 11 Feb 1941 mission successful.
Then they were moved and stationed in Malta for the Mediterranean campaigns running,

2nd May 1941 Jersey struck an Italian aircraft-dropped mine off Malta's Grand Harbour  sank next to the Grand Harbour breakwater. Thirty-five crew members were killed.

When Jersey sank it blocked the entrance to Malta's Grand Harbour, meaning movements into and out of the harbour were impossible for several days. The destroyers Kelly, Kelvin and Jackal were left marooned in the harbour until the wreck was cleared. Some of the ships that rescued the surviving crew had to take passage to Gibraltar.

On 5 May the wreck broke into two sections. It was only until after 1946 that the after section was cleared from the entrance, in a series of controlled demolitions carried out between 1946 and 1949. Further salvage and clearance work was done in 1968& 1971 to make the harbour safe for large vessels

Dive Holiday.

Going on holiday, ever thought of Malta!
Why Malta?
Malta, an archipelago in the central Mediterranean between Sicily and the North African coast, is a nation known for historic sites related to a succession of rulers including the Romans, Moors, Knights of St. John, French and British. It has numerous fortresses, megalithic temples and the Ħal Saflieni Hypogeum, a subterranean complex of halls and burial chambers dating to 3600 B.C.E.
 Malta's climate is typical of the Mediterranean and is strongly influenced by the sea. The Maltese Islands have a pleasantly sunny climate with a daily average of around 12 hours sunshine in summer going down to 5 to 6 hours in mid-winter.

 The Maltese Islands' clear blue Mediterranean sea is ideal for scuba diving. All three islands offer some unique diving experiences with an abundance of reefs, caves and wrecks that make diving here some of the most interesting in the Mediterranean.
The calmness and clarity of the sea makes for excellent visibility whilst  the risk of encountering dangerous fish is extremely low, creating the ultimate conditions for first time divers and beginners. For the more experienced divers, there are plenty of challenging dives to choose from.
 The three islands that make up the Maltese Archipelago -Malta the largest; Gozo the mythical isle of Calypso; and tiny Comino, famous for its Blue Lagoon - form a very special diving site at the heart of the Mediterranean.

The islands invite you to discover their natural harbours, bays, sheltered creeks, cliffs, reefs and wrecks. The waters here are some of the most limpid and clear in the world. Visibility is excellent down to around 60-70 meters from land sites.
So what we have done for people is give them the 1 click option to book a dive holiday.

 Tour HQ Tech Diving Malta Booking.

Unknown Wrecks Of Gozo.

                      

                        XLENDI PROJECT

Malta is a small independent country about 6o miles south of Sicily and has been a centre of civilization for more than 5,500 years as exemplified by its early Neolithic temples which date back to circa 2,000 years before the Egyptian pyramids. It has been a major trading port since Phoenician times and home to the Knights of St John between 1510 and 1800.

Adjacent to the main island of Malta is the island of Gozo, a small and quiet place which is off the beaten path. Xlendi Bay is a beautiful inlet with a sandy beach ideal as a swimming spot for both young and old. For many years this bay used to be a fishing village, but recently it has been transformed into a tourist attraction. As a tourist resort it is equipped with several tourist-oriented amenities, such as, bars, restaurants, holiday flats and hotels. Xlendi Bay is one of the prettiest places on the island. Its inky blue sea, the cloudless turquoise sky and majestic cliffs makes this place a must for tourists to visit. In the middle of the approach to this bay, about one foot below the surface of the water lies a hidden rock. This rock while being somewhat dangerous to navigation, is at the same time providential, since, in rough seas the heavy waves loose much of their force against it before continuing their course towards the beach. However, in ancient times it was an active trading centre used first by the Carthaginians and then by the Romans. Goods were stored in warehouses for re-transport and redistribution throughout North Africa, Italy and beyond.

The ancient port of Xlendi was larger than it is today. Situated at the mouth of a dry river valley, much of the original port has been silted over. Its approaches are bordered by high sheer cliffs that measure over 150 meters with a very shallow reef in the center of the narrow harbour entrance. Consequently, over the years numerous ships never made it into the harbour for this reason, ships abandoned anchors and jettisoned cargo to avoid wrecking. It seems that the amphoras and anchors around the reefs were all recovered by amateur divers in the 1960s. Some of these amphoras were brought to the archaeological museum in Gozo by divers from the British Navy who recovered this material from 20 meters of depth at the mouth of the Xlendi Bay. Interviews with the diving schools in Gozo suggest that further material was collected by divers in the last decades to clear all the remains in the areas up to a depth of 70 meters and their cargos of amphorae lie on the seabed across hundreds of meters in front of the cliffs. The underwater site which was explored in 2007 is situated in depths varying between 115 to 150 meters. It consists mainly of a sandy seabed punctuated by numerous rocky outcrops. The area is exposed to the prevailing north-westerly wind which, combined with the peculiar currents present created an environment of difficult sailing conditions and potential disaster.

Over the past five decades, many objects have been brought up from the shallower areas off the coast of Xlendi. Amphorae, anchors, urns and numerous other artefacts were raised by various diving expeditions and are now housed in the Gozo museum of archaeology. A quick glance at the objects visible on the seafloor suggests the presence of multiple shipwrecks. These vary in date from circa 300 BC to approximately 500 AD.

        Most of the intact pieces that were once at the base of Xlendi reef have been retrieved & most are in the Archaeology Museum in Rabat Gozo. I have tried to get a permit from the local government to dive this site just to take some photos and it has been impossible to get a reply.

        NO ONE CAN DIVE A ROMAN WRECK it is also on the instructors c-card and in the local regulations. MTA have started issuing Fine if you are caught diving in these areas.

Scuba Diving and is it SAFE!

SCUBA (Self-Contained Underwater Breathing Apparatus) diving. This interest can be harnessed to teach an exciting lesson on gas laws and their importance to SCUBA diving. Note: SCUBA diving is a sport filled with many inherent dangers and requires specialized training and equipment. Do not attempt any diving activity without proper training and certification, you wouldn't jump in a car and drive it or a truck with out the right training as it wouldn't be safe the same goes here if you follow your training yes it very safe so safe that there is less injury's than in football .

The dry air we breathe every day is composed of 21% oxygen, 78% nitrogen, and 1% other gases. Its average pressure at sea level is 1 bar. For SCUBA, this air is compressed into a SCUBA cylinder or "tank." SCUBA tanks can be made of steel or aluminum, each of these materials has pros and cons that impact the diver's decision on which type to use & weight to use.

The compressed air in the tank is delivered to the diver through a regulator, which reduces the pressure from the tank to match the ambient pressure. At the surface, ambient pressure is 1 bar and it increases by 1 bar for every 10 m in depth through which a diver descends. Note: Other gas mixes such as nitrox (an oxygen/nitrogen mixture with a greater amount of oxygen than air), heliox (a helium and oxygen mixture), and trimix (a mixture of oxygen, nitrogen, and helium) or even pure oxygen are also used for technical diving, but those mixes go beyond the scope of recreational diving and have depth limits.

A  rule of SCUBA diving with every agency  is to "never hold your breath." A look at Boyle's law explains why this rule exists. When a diver inhales air from a SCUBA tank, the air that enters the diver's lungs is at ambient pressure. If a diver inhales from the tank on the surface, the pressure in his lungs will be at 1 bar. If he inhales air from his tank at a depth of 30 m, the pressure in his lungs will be 4 bar (30 m / 10 m/bar = 3 bar from the water plus 1 bar from the air at the surface = 4 bar). Assuming the diver's lung volume is 1 L, we can complete the left side of the equation for Boyle's law. If a diver at 30 m has 1 L of air at a pressure of 4 bar in his lungs and ascends to the surface while holding his breath, we see that the diver's lung volume would increase to 4 times its typical volume. This increase will result in severe damage to the lungs, which can be fatal. The increase of volume with a decrease in pressure can also be seen in by a diver the gas bubbles exhaled as he rises to the surface. The exhaled air bubbles are small at depth and increase in size as they travel towards the surface. SCUBA instructors sometimes demonstrate this principle to their students by bringing a plastic bottle with a cap along on a dive. As the pressure increases with depth, the gas bubbles trapped in the bottle decrease in volume, shrinking the bottle. See the photo the gas bubbles exhaled as he rises to the surface. 

Boyle's law also has implications on the amount of air used from the tank with each breath. At 10 m (2 bar) twice as many oxygen and nitrogen molecules are inhaled with each breath. Deeper dives require closer monitoring of a diver's air supply because the diver uses his supply more rapidly. Another question students often ask in this discussion is, "How is the SCUBA tank impacted by these changes in pressure?" Because the tank is a rigid container, its volume is not altered with the change in external pressure nor is the gas it contains affected.

A SCUBA tank is a rigid container, therefore its volume is held constant. When a tank is filled, additional oxygen and nitrogen molecules are added to the tank and the pressure and temperature increase. If a tank is filled rapidly to 200 bar, its temperature can rise to as much as 150° F (65.6° C). Since all gas laws use absolute temperatures, this will then have to be left for some time to cool and re filled as once cooled the pressure will drop as the molecules reform tighter patterns.

Interesting phenomenon for divers using dry suits. A dry suit is a watertight garment worn by divers (typically over warm clothing) that serves to keep the diver warm by trapping a layer of air between the diver and the suit. Dry suits are usually worn in cold air and/or water temperatures.

During the dive, divers can add and remove air from their dry suits through their regulators. This allows them to adjust for changes in their suits' gas volumes due to pressure changes during assent and descent. If the air temperature is colder than the water temperature when the divers emerge at the end of the dive, they can become "vacuum sealed" in their suits due to the decrease in their suits' gas volumes. Divers can add air to the suits from their tanks, or unzip their suits, to release the "squeeze."

Also known as Dalton's law of partial pressures, this law states that the total pressure of a gas mixture is equal to the sum of the partial pressures of its component gases. As mentioned earlier, dry air is a mixture composed of 21% oxygen and 78% nitrogen. Both of these gases can have negative impacts on a diver at high pressures. Low partial pressures of oxygen are also dangerous but are only an issue for technical diving, which is beyond the scope of this discussion.

Oxygen can become toxic to a diver when the partial pressure of the oxygen breathed is above 1.6 atm. Symptoms of oxygen toxicity can include changes in vision, dizziness/vertigo, and seizures, all of which can be problematic for a diver and can lead to death. To calculate at what depth a diver might begin to experience symptoms of oxygen toxicity when diving with compressed air, we need to first calculate at what air pressure would the partial pressure of oxygen be equal to 1.6 atm or greater.

Nitrogen narcosis can result from a diver's exposure to high partial pressures of nitrogen during her dive. Symptoms of nitrogen narcosis most closely resemble those of alcohol intoxication. These symptoms appear more gradually than those of oxygen toxicity but also increase with depth.

Henry's law states that the solubility of a liquid is directly proportional to the partial pressure of the gas above the liquid. The implication of this law for SCUBA diving is that as depth increases (and therefore pressure) the amount of a gas dissolved in the diver's blood will also increase. Oxygen is consumed by the body's physiological processes, but nitrogen is physiologically inert. The longer that a diver remains at depth, the more nitrogen is dissolved in his blood.

During long dives a considerable amount of nitrogen can be dissolved in the diver's bloodstream. When the diver ascends the partial pressure of nitrogen drops, and due to Henry's law the dissolved nitrogen begins to come out of solution. Nitrogen bubbles form in the diver's bloodstream, which can lead to decompression sickness (DCS).(Mark powell- Deco for divers)

The symptoms of DCS and their severity depend on where in the diver's body the bubbles migrate and can range from soreness in the joints or blisters under the skin to death. Treatment for DCS typically involves several sessions in a hyperbaric oxygen chamber. In their training, divers are taught to stay within dive time and depth limits to minimize their risk of DCS and to ascend slowly from every dive.