War at sea


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War at sea

  1. 1. The War at Sea
  2. 3. Privateers A ship privately owned and crewed but authorized by a government during wartime to attack and capture enemy vessels.
  3. 4. <ul><li>David Bushnell’s American Turtle, was the first American submarine (to be used in warfare). Built in 1775, its intended purpose was to break the British naval blockade of New York harbor during the American Revolution. </li></ul>
  4. 5. <ul><li>With slight positive buoyancy, American Turtle normally floated with approximately six inches of exposed surface. American Turtle was powered by a hand-driven propeller. </li></ul>
  5. 6. <ul><li>The operator would submerge under the target, and using a screw projecting from the top of American Turtle , he would attach a clock-detonated explosive charge. </li></ul>
  6. 7. <ul><li>This 1875 drawing by Lt. Francis Barber is the most familiar rendering of American Turtle. However, it contains several errors, including internal ballast tanks and helical screw propellers. </li></ul>
  7. 8. <ul><li>This cutaway model of the American Turtle is in the submarine museum at Groton, CT. </li></ul>
  8. 9. <ul><li>The cask on the back of the submarine is its weapon, containing 150 lbs of black powder with a clockwork time fuse, for a delay of up to </li></ul><ul><li>12 hours. </li></ul>
  9. 10. <ul><li>Abaft the vertical propeller atop the hull is the screw by which means the bomb (which was roped to it) would have been attached to the hull of the target. </li></ul>
  10. 11. <ul><li>Once the screw was firmly attached the boat was expected to submerge to release it and the bomb. </li></ul><ul><li>The operator's hands hold cranks for both propellers; there were also foot pedals. </li></ul>
  11. 12. <ul><li>Visible in the lower part of the boat are the forcing pump for water ballast and the rudder control rod (the control bar would be depressed for port and raised for starboard). </li></ul>
  12. 13. <ul><li>The operator sat on a transverse beam. </li></ul><ul><li>Visible atop the hull is the hatch with its deadlights and, on the left, a ventilation pipe with a valve that would seal underwater. </li></ul>
  13. 14. <ul><li>This more recent drawing of American Turtle, is based on Bushnell's own written description, and is more accurate than the 1875 drawing by Lt. Barber. The most notable difference is the propeller; in Barber's drawing it is a helical screw, and here it is shown as a crude propeller. </li></ul>
  14. 15. <ul><li>Also note that this drawing does not show ballast tanks. To submerge, the operator simply flooded water into the craft until it was negatively buoyant. This left the operator knee-deep in water. A hand pump was used to remove the water for returning to the surface. </li></ul>
  15. 16. <ul><li>Drawing of the American Turtle, </li></ul><ul><li>attacking the HMS Eagle. </li></ul>
  16. 17. <ul><li>Drawing of the American Turtle, at the Connecticut River Museum in Essex, CT., which owns the only working, full-scale model of David Bushnell's 1776 invention, the American Turtle. </li></ul>
  17. 18. Print shows three views of the American Turtle, a one-man submarine designed and built by David Bushnell to attach bombs to British warships during the American Revolutionary War.
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