The Excelsior IV Log is a nautical instrument for measuring a vessel’s speed and distance travelled. When navigating a ship it is essential to be able to estimate the boat’s speed and distance travelled to determine its position at sea. In times past the only way to measure a ship’s speed was to throw a wood log into the water and observe how fast it moved away from the ship. In the 16th century, the log was fastened to a rope knotted at set intervals. The log was thrown over the stern (back) of the vessel and a crew member counted the number of knots that were paid out in a set time. From this, they could estimate the speed of the vessel through the water. This was known as streaming the log and is also the derivation of the knot as a measurement of nautical speed. The Walker’s Excelsior Mark IV instrument was designed for smaller vessels, such as yachts, launches and fishing vessels. Historical: Thomas Walker & Son was internationally renowned in the manufacturing of ships logs, founding father , Thomas Walker (1805–1871), an engineer in Birmingham, patented a mechanical log in 1878 which was a recording instrument that attached to a rail at the stern of a vessel connected by a long cord with a rotor which was towed behind the ship. The instrument dial recorded the distance travelled. Thomas Walker first went into business to manufacture stoves at 58 Oxford Street Birmingham. Walker’s self-feeding stove was widely lauded at the Paris Exhibition of 1855, winning a prize medal and kick starting the first of many notable innovations for the Walker family's manufacturing business. However, it wasn’t until working on an earlier ship’s log model invented by his Uncle that Thomas Walker became interested in the further development of this device, used to ascertain a ship’s speed. Walker continued to improve on the common log for the company of Massey & Sons and these improvements were deemed revolutionary. This log became a firm favourite of the West India Association (British-based organisation promoting ties and trade with the British Caribbean), being the most common log in use for two generations. It took until 1861 for Thomas Walker and his son, Thomas Ferdinand Walker (1831-1921) to patent the first Walker log of many. Together, with the introduction of the A1 Harpoon Log two years later, they established the Walker Log Business as a force to be reckoned with. By the time of his passing in 1871, Thomas Walker Snr had not only founded a family business with considerable staying power but also instilled a tradition of public service. Having sat as a representative on the Birmingham Town Council for 15 years and played an active role in public works, he was soon given the nickname of ‘Blue Brick Walker’. Much like his father, Thomas Ferdinand Walker changed the face of the maritime industry. His patent of 1897, the ‘Cherub’ log, was a notable departure from the past providing a far more accurate reading and replacing the majority of logs of the age. They were the first to produce an electric log and the Walker factory was one of the first to introduce the 48 hour work week for employees. The ship log was invented and made by a significant marine instrument maker and innovator of machinery. It demonstrates the huge leap taken to improve navigational accuracy at sea with an instrument that was in use for decades.Ship's Taff Rail Log, rope attached. Walker's Excelsior IV Log model. Nautical miles dials: units and 10's. "Walker's Excelsior IV Log", "Made in England by Thomas Walker, Birmingham"flagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, log register, taff rail log, taffrail log, marine navigation, a1 harpoon log, cherub’ log, walker’s excelsior mark iv log, ship’s log instrument, mechanical ship’s log, measure ship’s speed, nautical instrument, navigation instrument, massey & sons, thomas walker, blue brick walker, thomas walker & son, thomas ferdinand walker, 48 hour work week

An hourglass or sandglass is an instrument for measuring a defined time and can be used perpetually by simply turning it over immediately the top bulb empties. The clear blown glass is shaped into two equal sized bulbs with a narrow passage in the centre and contains uniform sized sand or glass particles in the lower bulb. The width of the neck regulates the constant flow of the particles. The glass is held in a stand with top and bottom of equal shape and size. Hourglasses can measure an infinite variety of time by gauging the size of the particles, the shape and size of the bulbs and the size of the passage between the bulbs, thus measuring hours or minutes or even seconds. Generally an hourglass sits between discs of wood at the ends, which are joined by long wooden spindles between the ends and tightened by screw caps. The length of time can be adjusted by adding or removing sand particles. The use of the marine sandglass (or hourglass) has been recorded in the 14th century in European shipping. A one minute sandglass was used in conjunction with the ship’s log for ‘dead reckoning’, (see below) that is, for measuring the ship’s speed through the water. They were also used to regulate ringing the ship’s timetable; for example a 4 hour sandglass was used for the length of the sailors’ watch, and a half hour timer for taking of readings for the ship’s log; the ship’s bell would be rung every half hour. It was usually the role of the cabin boy to watch and turn the sandglasses over at the exact time of them emptying their upper chambers and to ring the ship’s bell. Hourglasses have been used historically for many hundreds of years. Some have been used for timing church sermons, in cooking, in industry and at sea. Even today they are used for measuring the cooking time of eggs and timing a player’s turn in games such as Boggle and Pictionary. The sandglasses at sea were gradually replaced in the late 1700’s to early 1800’s by the more accurate chronometers (marine clocks) when they became reliable instruments. DEAD RECKONING (or Deduced Reckoning) Dead reckoning is the term used to describe the method of calculating the ship’s position from its speed and direction, used in early maritime travel, mostly in European waters. Both the (1) speed and the (2) direction of travel were recorded on a Traverse Board at half-hourly intervals during a helmsman’s watch of 4 hours. The navigator would record the readings in his ship’s log, plot them on his navigational chart and give his updated course directions to the next helmsman on watch, along with the cleared Traverse Board. This was a very approximate, but none-the-less helpful, method of navigation. The wooden Traverse Board was a simple pegboard with a diagram of a compass with eight peg holes along the radius to each of the compass points, plus a grid with ascending half hours in the left column and increasing ship’s speed in knots in a row across the column headings, with a peg hole in each of the intersecting cells. A number of wooden pegs were attached to strings on the board. By placing one peg consecutively in the direction’s radius hole, starting from the centre, and the speed holes when the half hourly reading was taken, a picture of speed and direction for the whole 4 hour watch was created. (1) To measure the ship’s speed a one minute hourglass timer was usually used to measure the ship’s speed through the water and help to calculate its longitude. A rope, with knots at regular standard intervals and a weight such as a log at the end, would be thrown overboard at the stern of the ship. At the same time the hourglass would be turned over and a seaman would start counting the number of knots on the rope that passed freely through his hands as the ship travelled. When the timer ran out the counting would be stopped. A timer of one minute (one-sixtieth of an hour), knots spaced one-sixtieth of a nautical mile apart, and simple arithmetic easily gave the speed of the ship in nautical miles per hour ("knots"). This would be recorded every half hour. The speed could however be inaccurate to the travel being affected by ocean currents and wind. (2) To calculate the ship’s direction a compass sighting would be recorded each half hour.Marine hourglasses or sandglasses were used from around the 14th to 19th century during the time of sailing ships. This hourglass is representative of that era, which is during the time of the colonisation of Australia. Hourglass or sandglass; an instrument used to measure time. Two equal sized clear glass bulbs joined with a narrow passage between them, containing equal sized particles of sand grains in lower bulb. Glass sits in a brass collar at each end, in a frame comprising 3 decorative brass columns or posts, each attached top and bottom, using round screw-on feet, to round brass discs. Disc have Roman numerals for the numbers 1 - 12 pressed into their inner surfaces and hieroglyphics on the outer surfaces. Roman numerals on inner surface of discs " I II III IV V VI VII VIII IX X XI XII " Hieroglyphics impressed on outer surface of discsflagstaff hill, warrnambool, shipwrecked coast, flagstaff hill maritime museum, maritime museum, shipwreck coast, flagstaff hill maritime village, great ocean road, horology, hourglass, hour glass, sandglass, sand glass, timing instrument, dead reckoning, deduced reckoning, finding latitude at sea, sandglass with hieroglyphics and roman numerals, hourglass with hieroglyphics and roman numerals, brass hourglass