The Marine Chronometer – A Mechanical Masterpiece

We’ve studied the nascence of the marine chronometer. Examined the tireless work of John Harrison and the disgraceful way he was treated by the Board of Longitude. It’s time now to see the instrument in its present state.

Just a little bit of recapping. In 1765, Pierre Le Roy, who’s father, Julien, had been clockmaker to Louis XV, with Pierre following in his father’s footsteps in this regard, invented the compensation balance. Incidentally, and I apologize if I sound pernickety, but the item we’re discussing is always named simply a ‘balance.’ Never ‘balance wheel.’ However, Pierre’s invention consisted of weights placed on the balance rim and/or the crossings, or spokes. These would move around the rim and would change the moment of inertia.

Then the irascible, but brilliant Thomas Earnshaw invented his bi-metallic balance. This consisted of the steel rim, inside which was pressed a brass insert.

The brass and steel expanded and contracted at different rates, much like Harrison’s gridiron pendulum. This became the standard balance and helped with temperature compensation no end.

It was found, however, that it suffered from what is known as middle temperature error. The chronometer could be regulated to keep perfect time in cold temperatures and again in a heated atmosphere, but when the temperature was in between these two points, the timing varied. In 1776, John Arnold, when he wasn’t at war with Earnshaw, invented the helical balance spring and this, together with Earnshaw’s bi-metallic balance became the standard for over a hundred years, particularly when used with Earnshaw’s spring detent escapement, or Arnold’s pivoted type. The latter saw some success on the Continent, but in England, the spring detent held sway.

Then, in about 1900, Charles Guillaume developed a nickel-steel alloy which he named Elinvar.

This has a near-zero coefficient of expansion and is invaluable for spring making. Middle temperature error was almost completely done away with, and the chronometer that we know today came into being.

They were, however, hideously expensive. Being instruments that had to keep perfect time, they couldn’t be mass produced like other types of clock. In fact, it wasn’t until the great American clock company, Hamilton, in the early to mid 20th. century that mass production methods were developed.

There are basically two types of chronometer. The 2 day and the 8 day. The 2 day has to be wound every day, while the 8 day must be wound every other day.

Incidentally, don’t confuse the chronometer with the ship’s clock. They’re entirely different animals. The ship’s clock didn’t appear until late in the 19th. century, and it was fitted with a strike mechanism that struck ship’s time. One bell for 12.30, two bells for 1 o’clock, three bells for 1.30, etc., all the way round to eight bells at four o’clock, when it would start its cycle again. But it was most certainly not a chronometer.

Strictly speaking, a chronometer is what it is only if it has a spring or pivoted detent escapement. It is true that the detached lever escapements made by the Swiss are of such high quality now, that they keep extremely fine time and are occasionally called chronometers.

But, like any other clock or regulator that has the function of timekeeping alone, there are no other complications, such as strike, chime, moonwork, or anything else that would put stress on the time train in lifting levers or detents to allow for these features to operate.

All chronometers, too, are fitted with fusee mechanisms and maintaining power, both of which we’ve discussed. The movements are fully jewelled and the workmanship exquisite. The dial carries the hour and minute rings, of course, and there’s a small seconds chapter ring, usually just below the 12 o’clock position.

These days, quartz clocks have taken over. It’s true that they’re extremely accurate, but soulless. They can’t compare to the magic of the mechanical movement.

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Marine Corps Training More Officers

Marine Corps has set a goal growing the force to 202,000 Marines, which has been going smoothly on the enlisted side, but it is more time consuming to produce Marine officers, and the Corps has been trying to keep pace.

It takes about one year before a Marine officer can finish all their schooling and be assigned to the fleet as a 2nd Lieutenant in charge of a Marine platoon. The Marine Corps puts its officers through intense training to ensure they are ready to lead Marines.

Ground zero for training Marine officers is The Basic School (TBS) at Quantico, VA. TBS normally graduates about 1,600 lieutenants each year; right now they are on target to graduate 2,000 officers, which has not lessened the quality of the training, but has put a lot of stress on the NCOs who train the men and women.

The Corps is expected to reach its new size by looking to take on 2,050 officer candidates in 2009 and 2,108 by 2010.

Despite the increased numbers, the goal of TBS is still the same: teach these new Marine officers the basics of weapons, tactics and how to manage small units like platoons and companies.

There are four ways for men and women to become Marine officers: Officer Candidate Course, Platoon Leaders Class, enlisted to officer programs and finally through graduating from the Naval Academy or the Naval Reserve Officers Training Corps. A full 64% of Marine officers currently come through the first two options.

The path into the Marine Corps is more direct for enlisted Marines. After graduating from a 12-week basic training known as “boot camp” they can officially call themselves Marines. From there they go to their advanced school to study whatever it is they will do in the Corps: artillery, infantry, intelligence, etc.

Once an enlisted Marine gets settled, he can then further his civilian educational training by using Marine Tuition Assistance (TA), which he can use at any accredited vocational school, community college or university of his choice.

And since many Marines are deployed abroad or are on Naval ships all over the world, they can also using their TA benefit at an accredited online school, so that they can prepare for their civilian career from anywhere in the world.

And the best thing about TA is that Marines pay nothing-out-of-pocket – the military pays the schools directly.

Some schools also offer military spouse scholarship to the spouses of active-duty Marines. Some scholarships allow a Marine spouse to enroll in a training program at no cost when the Marine uses TA to enroll at that particular school.

Online schools come in all shapes and sizes, so Marines should make sure that the school is nationally accredited. The Distance Education and Training Council (DETC) is a government-approved accrediting body that many online schools look to.

Students should also look for live student support, so they can call up a school representative when they have questions about their course or program. Many online schools also work with service members on a consistent basis and can be very helpful with TA paperwork.

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Marine Biologist – Studying Marine Mammals

Studying marine mammals may be one of the most interesting parts in a marine biologist’s profession. There are 3 main orders that you need to know about. Each category has its own unique mechanism, feeding pattern and characteristics. These animals tend to live in different places as well, others in groups and the rest in families or alone. Once you become familiar with their lifestyle and features, you get to appreciate the species more.

Cetacea Order

The whole lifecycle of the order Cetacea is aquatic. There are a couple of sub-orders founded ont he feeding mechanism – Odonticeti and Mysticeti. The sub-order Mysticeti includes baleen whales, blue whales, minke whales, grey whales and right whales. The whales feature mechanisms to boost the success feeding.

The sub-order Odonticeti includes animals like killer whales, dolphins, toothed whales and porpoises. River and coastal species reside in small home ranges if they are offshore. Others prefer warm equatorial waters, while the rest are located in every ocean like the bottle-nosed dolphins and killer whales. Some animals like big baleen whales move from the tropics for winter breeding to high latitudes for summer feeding. Animals propel themselves using the broad and boneless tail flukes. They also shed skin and exude oil as much as 12 times per day to reduce friction.

Pinnipedia Order

These animals adapt to the environment through a variety of processes. Heat conservation is done and get a low SA/V ratio and develop insulation through their hair and blubber. All the animals moult, after breeding in the summer while the others should stay out of water until everything is done.

The respiration is done by exhaling before the deep dives. They have relatively high concentrations of haemoglobin and myoglobin. The heart of the animals drop during deep dives and the blood is limited to the heart and brain. Dives can be as deep as 1700m, lasting anywhere between 80 to 160 hours.

Sirenia Order

Sirenians are sought mainly for their hide, oil and meat. They spend their entire lives in the water and are the only aquatic animals labeled as herbivores. The flat tail propels itself via paddles. These can walk at the benthic or move backwards. Locomotion is usually slow but they can also burst at around 13 knots. Sirenians inhale before they dive, just like whales.
When they breathe, they can swap about 90% of lung volume.

Manatees can see very clearly underwater, while taste and smell are retained. These touch when they greet each other and lead to chirps, between calf and mother. Dugongs can live for as long as 70 years but fecundity is rather low. The animals reach puberty at 10 years old and produce only 1 calf every 5 years. Their population has to be protected to maintain the ability to recover from environmental stress and hunting.

Interacting with Man

All animals have interactions with man, although sirenians are the most widely known to be friendly towards humans. Fishing nets and fishing lines tend to be a problem for most of these animals.

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