30 of the Punniest ISM ISPS MLC Internal Auditor Rotterdam Puns You Can Find

Swimming is noted in many of the classics as relating to heroism and religion. Nicolas Wynman's Dialogue Concerning the Art of Swimming (1538) is the first recorded written document on swimming methods. Swimming first appeared in the Olympics in 1896, paralleled to the development of the swimming pool. Swimming the English Channel is the most publicized non-Olympic event. It proves excellence in strength and endurance. Matthew Webb from England was the first man to cross the English Channel in 1875, and later Gertrude Ederle of the Unites States of America became the first woman to cross in 1926. ™

Snorkeling to view exotic fish and aquamarine life is a much-loved vacation adventure. In ancient times snorkels were crafted from hollow reeds found in lakes and marshes. Pliny the Elder, a first century A.D. Roman makes reference to the snorkel, so the activity holds rank as one of the oldest recorded water sports. Loenardo da Vinci created a more modern snorkel when the Venetian senate summonsed him to do so. Divers attached this hollow tube to leather helmets

The present-day diver's snorkel is typically a J-shaped tube that is open at the top and has a mouthpiece at the other end, usually no more than 2 ft (61 cm) long.

American West-coasters go wild riding the waves on a wooden plank known as a surfboard. Originally, surfing developed in Hawaii in the nineteenth century. It became popular in California in the 1920s, and became a hit youth sport in the 1960s.

Surfers originally used long, cumbersome wooden boards but now ride lightweight synthetic boards that allow a greater degree of maneuverability. Hawaii holds annual international surfing championships.

Water polo originated in England in 1870, and American joined the bandwagon in the early 1900s. Many club and college teams exist for this rigorous sport. Americans gave the game a twist by using a softer rubber ball in a larger pool, a game known as softball water polo. Violence and rough play ended this faction of the sport, and today only the hardball version continues to be played worldwide. Men began Olympic level water polo in 1900, and women first played in the Olympics in 2000.

Diving, another favorite Olympic sport, initiated competition in 1871 off the London Bridge. Diving is now a popular sport at the high school and collegiate level, and is an amazing display of strength, control and agility.

Purpose of Shaft Grounding Systems in Marine Engineering

It's Science 101:

Electricity and water don't mix.

That maxim is no clearer than in marine engineering, where seawater mixed with the electrical systems of a propeller can cause corrosion, loss of efficiency and system failure.

To completely protect a ship it's important to electrically ground the ship's propeller to the hull. Grounding the propeller limits corrosion and damage to the propeller's shaft, bearings, and gear box.

Every motor-powered marine vessel should have some sort of shaft grounding system installed.

Shaft is Critical

One of the most critical parts in a marine vessel's propulsion system is the shaft. Shafts that become corroded over time lose their efficiency. An overly corroded shaft can lead to system failure.

A grounding system is important.

That's because as electricity runs through the engine to the propeller it mixes with water. The combination of the two - called an electro-chemical reaction - causes corrosion to the shaft.

The shaft provides thrust to move the vessel forward.

Shafts that become corroded over time due to electrochemical reactions with seawater lose their efficiency. They become weaker at transferring energy from the vessel's engine to its exterior propulsion system.

A grounding system is also necessary to protect the drive-motors bearings from electrical damage. Excessive capacitive discharge can lead to electrical bearing failure.

At the same time, corrosion left unchecked can shorten any ship's lifespan. This may cause maintenance problems too occur sooner than otherwise.

How Does It Work?

The principle behind shaft grounding is fairly simple.

In most marine vessels, propellers driven by electric current create charges along the exposed sections of the prop. A grounding system insures that as small a charge as possible escapes. The system is designed to ground out all electricity in the ship's hull.

The grounding prevents free-flowing electrons from doing their damage.

As a result, both the propeller and engine are able to run longer and stronger due to less damage. In most cases, each propeller shaft should hold a ground system.

One type of a grounding system uses a layer of metal outside the shaft. This way, any electrochemical potential from seawater will be attracted to the outer layer as opposed to the shaft itself.

Types of Grounding Varies

The best kind of grounding system to use depends on the vessel.

There are different choices and owner can choose.

Some factors include the type of engine, size of the ship and composition of the hull. Also, systems get more complicated depending on the amount of charge handled. At the same time, the number of propellers and engines a vessel has also affects the choice of system.

Consult a Professional

It's not always possible to prevent 100 percent corrosion on or within a marine vessel. But the importance of shaft grounding systems in marine engineering should not be overlooked.

Talk to a professional for the most current information on the purpose of grounding systems.