By Dwight Howse
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@@ HomeHome @@ bySeaSea Dwight Howse In April 1895, at age 51, after a 35-year career desire to see new cultures and destinations, or in various capacities sailing primarily on simply the romance and lure of the sea, cruisers freighters, Captain Joshua Slocum left Boston set out for extended periods of time living on in an 11.2 m gaff-rigged sloop named Spray. board sailing yachts, travelling to various He embarked on a busman’s holiday that would destinations around the globe. see him sail single-handed more than 46,000 nautical miles to become the first person to Captain Slocum spent a career around boats as circumnavigate the globe alone. He recounted cabin boy, mate, captain, and boatbuilder. As his adventures over the three year period in his such, he developed the navigation and other book entitled Sailing Alone Around the World. complementary seamanship skills that enabled Having no business driver to undertake this him to sail safely and confidently. On the other voyage, it might be said that Captain Slocum hand, I would suggest that most modern set the bar for a new class of recreational sailors. recreational cruisers contribute significantly Driven by a thirst for adventure or escape, a less than 35 years to “learning the ropes.” 28 The Journal of Ocean Technology • Essays Copyright Journal of Ocean Technology 2011 to participate in the exciting and satisfying world of recreational cruising. Navigation An old Breton prayer reads, “Oh God, thy sea is so great and my boat is so small.” Those few words exemplify the mindset of sailors who must constantly respond to the question “Where am I”? Without fail, that question is followed up by part b: “How do I get from here to where I want to be”? The Designer provided great oceans to travel but, apparently, signposts were in short supply. No doubt, incredible feats of navigation have been accomplished with little or no technology. Polynesians populated the remote islands of the Pacific and later sailed regularly from the leeward islands of Tahiti to Hawaii and back based on an intimate knowledge of winds, ocean swells, sea animal behaviour, cloud formations and of course the rise and fall of the stars. The Phoenicians, Chinese, DWIGHT HOWSE Norsemen and Arabs each ventured on long distance trade and raid routes with little instrumentation. In their time, the marine compass, the They are young people, families, and retirees astrolabe, the backstaff and sextant each with varying degrees of skill and relatively made significant technological contributions little infrastructure support, yet the vast majority to answering the perennial “Where am I?” sail safely, confidently, and in comfort along question. Nonetheless, it wasn’t until John their chosen tracks. The key factor that enables Harrison invented the marine chronometer in today’s recreational cruisers to undertake these the 1700s that longitude could be accurately long voyages is the development and adoption determined. Even our Captain Slocum of a suite of ocean technologies that greatly circumnavigated the world with only a log, eases the burden of knowledge and experience a compass, chronometer, and sextant as required to safely enjoy recreational cruising. navigation instruments. These instruments, The challenges of navigation, communication, however, require knowledge, practice, boat-handling, and even provisioning have mathematics, and a certain degree of luck to been successfully parried by technology. use since inclement weather and a rolling boat Technology has enabled a broad cross-section often limit the precision that can be obtained. Copyright Journal of Ocean Technology 2011 Technology to the Wind, Vol. 7, No. 1, 2012 29 Two technologies developed early in the of plotting courses with dividers and parallel twentieth century have contributed immensely rules on paper charts, today’s navigator can to the safe navigation of recreational yachts. plan routes with a series of waypoints and They are both similar in that they rely on calculate headings, distances, and estimated echolocation; however, one uses radio waves times of arrival with the press of a few buttons while the other uses acoustic waves. Here, or a few touches on the screen. While I would I refer to radar and sonar, respectively. By not suggest that paper charts have become constantly monitoring the returns from radio redundant, I would suggest that their use pulses sent sequentially in a circle around a has been relegated to more of a backup role. yacht, the master can see land, traffic, and An electronic chart can provide automatic weather patterns in the local area using a radar warnings of fixed hazards such as rocks, reefs, system. Similarly, an acoustic pulse reflected and wrecks. It can also provide calculated and off the bottom informs the master whether or real time information such as tides, currents, not there is sufficient depth and enables the and even weather. Why stop there? Why not sailor to recognize when depth contour lines overlay radar information on the same display? are crossed. With reference to a chart, the Now, with a radar overlay, even local traffic knowledge of landforms and depths provide appears in the same display as the chart and the sailor with valuable location cues. there is an additional level of confidence in position when the radar returns register well Ocean navigation signposts were not broadly with the electronic chart shorelines. available to the common person until the twentieth century with the installation of long An autopilot contributes to the ability of a range radio positioning systems such as Loran short-handed cruising crew to maintain watch and the early attempts at satellite positioning. on long passages. By relieving the burden of a The breakthrough navigation technology of hand on the wheel or tiller, a single individual our time is of course the Global Positioning can maintain watch, plot locations, and make System (GPS). Sailors have crossed oceans any necessary adjustments to sails while for thousands of years but it was less than another crew member or two are off duty. A twenty years ago, in 1994, that the GPS good autopilot will enhance the stamina of became fully operational. Through altruism the crew by relieving the relative drudgery of or other motivation, with the launching of 24 playing the wheelsman. Cruiser’s experience active satellites, the United States effectively with autopilots has varied significantly. Slocum gifted the world with a signpost every 10 m reported that he was able to go several thousand or so around the globe. Three other systems to miles by just lashing his tiller – a very crude augment this capability are in various stages autopilot. Meanwhile, Sir Francis Chichester of development and deployment: GLONASS reported considerable frustration with the (Russia), Galileo (European Union), and autopilot used during his 1966 circumnavigation. COMPASS (China). Suddenly, practically Today’s autopilots are able to be integrated anyone with a GPS receiver can rattle off with the electronic chart to follow a series of latitude and longitude. The perennial “Where waypoints rather than being restricted to just am I?” question has been perennially answered. maintaining a heading. However, for now at least, the crew will still have to make necessary A GPS receiver is practically ubiquitous now sail adjustments. as the fundamental geo-referencing instrument for navigation. The integration of GPS with a As a platform for the presentation of pertinent database enabled a Geographical Information information for safe navigation, the electronic System (GIS). A GIS is able to effectively chart system is unparalleled. A few words of maintain and present geo-referenced nautical caution are warranted, however. Firstly, the information and, therefore, an electronic chart information presented is only as good as the and pilot book has become possible. Instead data available in the electronic chart. Some 30 The Journal of Ocean Technology • Essays Copyright Journal of Ocean Technology 2011 DWIGHT HOWSE As a platform for the presentation of pertinent information for safe navigation, the electronic chart system is unparalleled. The information presented, however, is only as good as the data available in the electronic chart. Note the poor registration between the radar (purple) and the chart showing a discrepancy of about 0.75 nm. bathymetric surveys are quite dated and may Frequency (MF) and High Frequency (HF) radio sometimes have significant inaccuracies. provide voice and data communications over Secondly, it is critical that the datum used for hundreds or even thousands of miles depending the chart and the GPS position match. Be sure to on the propagation characteristics. For the check your manual for datum selection options. ever-thrifty cruiser, these services are essentially free once the radio has been purchased. Communication For weather information, traffic updates, safety, Cellular telephones are now commonly used business transactions, friend and family contact, while coastal cruising around populated areas; and entertainment, communications are now however, long range cruisers and even gunkholers considered essential on board any vessel. [those who cruise from place to place, spending Captain Slocum and other sailors before him the nights in coves] will often find themselves may have circumnavigated the globe with their out of range or attempting to use the bosun’s communication systems limited to a visual chair to go up the mast in search of a better range of a very few miles. Nonetheless, few signal. For the long range cruiser, recent modern cruisers would be satisfied with such technology has enabled access to the global (or isolation. Fortunately, in December 1901, nearly so) satellite communications offered by Guglielmo Marconi demonstrated the capability Inmarsat, Iridium, and Globalstar systems. of transoceanic radio communication from Inmarsat relies on a network of geostationary Poldhu in Cornwall, England, to St. John’s, NL, satellites and, therefore, does not cover the poles, Canada.