Captian Jack's Basic Navigation - Softcover

Über die Autorin bzw. den Autor

Captain Jack I. Davis and his first mate Mary (Mary is an excellent sailor and registered nurse), have lived aboard their forty-three foot Wauquiez ketch since 1984.

His first career was banking and his second career was computer software for banks but his main love has always been sailboats. During this time he owned several power boats and enjoyed water skiing and fishing but yearned for the blue water which the Texas lakes did not offer. He had made several ocean crossings before obtaining his first U. S. Coast Guard Captain's License in 1984 at which time he started boat deliveries in earnest.

The majority of the deliveries have been from Texas to Florida and the West Indies with one delivery completely circumnavigating the Gulf of Mexico. In May 1998, he made his sixty first open water crossing of the Gulf of Mexico.

Between deliveries he has taught countless sailing and navigation classes. His sense of humor and teaching style, as demonstrated in this book, keep his students coming back for more. He has continually upgraded that first license and now holds a U. S. Coast Guard Master's License, Steam, MotorSail and Sail.

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From Chapter 1: Chapter 1 DISTANCE SPEED AND TIME Being a good navigator can't be traced to one single skill. It's a composite of many talents. Today, with the availability of electronic aids, such as GPS (Global Positioning System), you could cross an ocean without the navigational talents in this book. Provided there is no electronic failure. I see inexperienced people go to sea without the proper abilities. Many make their landfall without major problems but there are some who do have complications. I talked to one of these people and his comment was, When the electronics failed, it was the most frightening experience of my life. I was not only lost, but I didn't even know where I was before I was lost. Which brings us to: Rule # 1 - Always maintain a D. R. These letters stand for Dead Reckoning. All the time you are under way, keep a record of the course, speed and the elapsed time. I can not overemphasize the importance of keeping a systematic record of your distance, speed and elapsed time, while at sea. For the electronic sailor who does not maintain a DR, I recommended he glue a mirror just below his GPS or Loran. When the electronics fail, he can then look in the mirror and see who is lost. In order to plot your course, time and speed onto your chart, you must learn to calculate distance, speed and time. Don't worry about the difficult calculations. The most complicated math involved in our navigational procedures is elementary math. As simple as it is, you should use your hand held calculator to further simplify checking the answers. Everyone does a certain amount of these calculations while driving from point A to point B. If these points are 60 miles apart and your car speed is 60 miles per hour, it's going to take an hour to make the trip. You can conclude: You're traveling one mile per minute at 60 miles per hour, in 30 minutes you will be halfway there. Navigation is that simple. In this case you are solving for distance. You know your speed (60 mph) and the elapsed time (30 minutes). The formula to solve this problem is Distance = Speed x Time. We put down 60 mph for speed and .5 for elapsed time (30 minutes is one half of an hour, or .5). Then 60 times .5 equals 30, or 30 miles, the answer to the problem. We may also need to solve for speed. This formula is: S = D / T (The / symbol represents Divided By). If we have made 30 miles in 30 minutes (.5 hours) we divide 30 by .5 which equals 60 (mph). To solve for time, the formula is T = D / S. If we have traveled 30 miles at a speed of 60 mph, we divide the 30 by 60 which equals .5 (.5 hr = 30 minutes) These formulae are critical. If you use the wrong formula, as is so easy to do, the answer will definitely be wrong. Instead of trying to remember all these formulas there is a better solution. Please be certain you understand this and do not try to remember the formulas. Always write the formula on the work paper. In the examples given for distance, speed and time, the examples were mph (miles per hour) and the distances were statue miles, used by most landlubbers. The statue mile is 5,280 feet, but the nautical mile is 6,080 feet. Everything shown from here on will be nautical miles (nm) and knots (kn). Note, I did not say knots per hour, which is incorrect. A knot is the speed of 1 nautical mile per hour. Derived from the Common Log where the number of knots (about 25 feet apart) which ran out in a quarter minute gave a direct reading of the ship's speed. Thus, if the log was streamed and six knots ran out before the quarter-minute glass ran out, the ship's speed was six knots. To say 6 knots per hour is, strictly speaking, incorrect. I use the abbreviation hr for hours and min for minutes. Remember: when you multiply or divide hours and minutes, you must convert your minutes to fractions of an hour. For instance: 2 hr 15 min must be converted to 2.25 hr (divide your minutes by 60). 15/60 minutes equals .25 hr. When you have found an answer that is hours and fractions of hours, you must convert it back: 2.25 hr must be converted to 2 hr 15 min (You multiply the fraction by 60). .25 X 60 equals 15 min. If I am using a hand held calculator, I carry all the decimal places hat the gadget will allow me to carry: 2 hr 22 min (22/60 equals .36666666). If I must use long division or multiplication (with paper and pencil), I round off to .367. The difference will be acceptable. It is important to work all of the following problems, even if you think you know how to do them. You may be surprised. The answers are at the end of this chapter. DISTANCE

SPEED

TIME 1. ____________?

7 kn

3 hr 2. ____________?

5.5 kn

4 hr 3. ____________?

13.5 kn 3.5 hr 4. ____________?

17 kn

3 hr 10 min 5. ____________?

24 kn

3 hr 10 min 6. ____________?

2.7 kn

.8 hr 7. ____________?

42.4 kn 16 min 8. ____________?

23 kn

46 min 9. 43 nm

6.2 kn

__________? 10. 32 nm

8.5 kn

__________? 11. 35 nm

12.3 kn __________? 12. 17 nm

28 kn

__________? 13. 15 nm

3.5 kn

__________? 14. 17.8 nm

29 kn

__________? 15. 6.6 nm

19.3 kn __________? 16. 8.1 nm

16.9 kn __________? 17. 22 nm

_________?

29 min 18. 23.8 nm

_________?

0.6 hr 19. 12.3 nm

_________?

19 min 20. 34 nm

_________?

88 min 21. 24.1 nm

_________?

77 min 22. 16.5 nm

_________?

0.48 hr 23. 18.9 nm

_________?

0.77 hr

24. 17.1 nm

_________?

1.5 hr In school, the stated problem was one of my least favorite problems. Life, as it turns out, is a stated problem. Certainly, navigation on a small boat is a stated problem. Don't be intimidated. Try to look at each problem as if it is a real life situation and you are the navigator in charge. 25. The distance between two buoys is 14 nm. The vessel's speed is 11 kn. The running time between the two buoys is ______________? 26. Your boat's speed is 12 kn. The speed of the current is 3 kn. What is the speed of your boat over the bottom while going upstream against the current __________? 27. Your boat's speed is 12 kn. The current's drift is 2 kn. (The speed of a current is called drift). What is the speed of your boat over the bottom as it travels downstream with the current ___________? 28. If you have a 2 kn current and can make 13 kn with a 6 nm run in each direction, how long would it take for a round trip _____________? Be certain to work this problem as two separate legs then add the results together. The answer will surprise most folks. 29. Point "B" is 59 nm from point "A" on a course of 345 degrees true. The current sets 165 degrees true at a drift of 1.7 kn. If your vessel's speed is 12.6 kn, how long will it take you to reach point "B" from point "A"____________? You already know drift is the speed of the current. Now, here is a new term: Set. Set is the direction the current is going. 30. Your course from "B" to "A" is north on a leg of 10 nm. Your boat's speed is 10 kn. The current's set is 180 degrees with a drift of 4 kn. What is your speed over the bottom ____________? 31. Your vessel is making way through the water at a speed of 13 kn. Your vessel traveled 30 nm in 4 hr 23 min. What current are you experiencing ___________? DISTANCE SPEED TIME ANSWERS 1. 7 kn x 3 hr = 21 nm 2. 5.5 kn x 4 hr = 22 nm 3. 13.5 kn x 3.5 hr = 47.25 nm 4. 17 kn x 3.1666666 = 53.8333 nm 5. 24 kn x 3.16666 hr = 75.9 nm 6. 2.7 kn x .8 hr = 2.16 nm 7. 42.4 kn x .266666 hr = 11.30666 nm 8. 23 kn x .7666666 = 17.6333 nm 9. 43 nm / 6.2 kn = 6.9354838 hr or 6:56 hr & min 10. 32 nm / 8.5 kn = 3.7647058 hr or 3:46 hr & min 11. 35 nm / 12.3 kn = 2.8455284 hr or 2:51 hr & min 12. 17 nm / 28 kn = .6071428 hr or 0:36 min 13. 15 nm / 3.5 kn = 4.2857142 hr or 4:17 hr & min 14. 17.8 nm / 29 kn = .613793 hr or 0:37 min 15. 6.6 nm / 19.3 kn = .341968 hr or 0:21 min 16. 8.1 nm / 16.9 kn = .4792899 hr or 0:29 min 17. 22 nm / .483333 hr = 45.517 kn 18. 23.8 nm / .6 hr = 39.666 kn 19....