April Skills Quiz: discussion and answers

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Gary Wyngarden

1. The correct answer is b. 100 yards. With 858 responses in, 27% got this right. Uh-oh. I guess this means 73% of us might end up in prison. They might have internet access to the site from prison, but sailing could be difficult! Any approach of less than 500 yards must be at minimum speed. Less than 100 yards requires authorization on VHF-16. Source is the Coast Guard Web Site. 2. The correct answer is c. Both outhaul and halyard eased a bit. 54% got this right. In his book The Sail Trim Users Guide, our Sail Trim Forum expert, Don Guillette says: "A deep sail produces more power and acceleration and is used in light air (3 knots to 5 or 6 knots) to medium air (6 to 10 knots). . . . Increasing the tension on the above controls (mast bend, outhaul, reef) reduces the draft depth and decreasing the tension increases the draft depth." Later. "A draft position aft produces more power and is used in light-to-medium air. . . . The halyard is the primary control for positioning draft position in the sail. . . . Decreasing the halyard tension moves the draft position aft." 3. The correct answer is c. an alcohol burner fire can be safely extinguished by water. 33% got this right. In his The Annapolis Book of Seamanship, John Rousmaniere says "Small alcohol fires...should be immediately drenched with water. . . . Gasoline, diesel oil, or grease fires should be attacked with a Type B extinguisher. . . . Electrical fires should be fought with a type C extinguisher." 4. The correct answer is a. A nautical mile on a NOAA chart is always equal to one minute of latitude. 52% got this right. A minute of longitude varies in length down to essentially zero at the poles. Not all charts have mileage scales on them. A nautical mile is equal to about 15% more than 5280. The source is Coastal Navigation published by the ASA and confirmed with other texts. 5. The correct answer is b. Alter course to port. 56% got this right. In a channel marked with range lights (or range markers), the lights (or marks) must be visually kept in line to assure you are in the channel. If the top light is out of line to your right, altering course to port will put them back in line and put you back in the channel. Source again is Coastal Navigation and again confirmed with other texts. 6. The correct answer is c. A load test. 26% got this right. An open circuit voltage test (answer a) or a specific gravity test (answer b) will tell you the state of charge of the remaining capacity of the battery, but they won't tell you anything about how much capacity remains. In other words, you could have a battery with little remaining capacity, but that capacity could be fully charged. Calder says to monitor the voltage drop as you attempt to start the engine with the kill switch engaged. The voltage will likely drop from say 12.6 or 12.7 volts down to 10.5 immediately but then should stabilize. If it continues to fall, you've got a problem battery and should conduct a full capacity test (more involved and time consuming). Source is Nigel Calder's Boatowners Mechanical and Electrical Manual. 7. The correct answer is b. a course of 290. 61% got this right. You calculate this by creating a vector diagram. First draw a line from your position to your destination. Second draw a line from your current position with a direction equal to the set of the current (it's magnetic direction) and a length equal to its drift or speed. Set your dividers to a length equal to your boat speed and place one point of your dividers on the end of the second line. Make an arc that intersects your first line. Draw a third line from the end of the second line to the point where your arc intersects your first line. Use your parallel rulers to walk the direction of the third line over to your compass rose and read the heading you should steer. Source is Coastal Navigation. 8. The correct answer is a. a course of 270. 69% got this right. A gps measures course made good, not heading steered. Your goal in the exercise in question 7 was to determine what heading steered would result in a course made good of 270. Consequently if you did the right thing in question 7, your gps should be displaying a course made good of 270. An easier approach to the answer in question 7 would just be to steer up current until your gps shows a course made good that will take you directly to your destination. However, if your gps is broken, it's always nice to know the old fashioned way. 9. The correct answer is d. Significantly ease or release the mainsheet. 18% got this right. Neither Russell Coutts nor Dennis Conner returned my calls to get their input on this question, so I'll take the heat myself. If you are sailing on a broad reach in 25 knots of true wind, you've got to be approaching your hull speed...let's call it 6 or 7 knots. Making a 90 degree turn at that speed even under power with no wind or waves would create a lot of centrifugal force and heel. Add the wave action kicked up by a 25 knot wind and you've compounded the force. If you are sailing at hull speed on a broad reach in 25 knots of wind, your apparent wind is maybe 19 knots. In a matter of a few seconds as you go through your turn to head upwind, your apparent wind increases to say 31 knots, an increase of over 60%. That's bad enough, but the strength of the wind increases with the square of the velocity change so its force on your sails has increased about 2.5 times (1.6 times 1.6). Add together the centrifugal force of the turn, being beam-to the waves, and an increase in force of wind of 2.5 times and you have a formula for at worst a knockdown, at best enough heel and weather helm to lose rudder control (and maybe spill your beer too!). My answer: take the turn wide, release the mainsheet as you begin the turn to spill wind, luffing the main. AFTER your turn is completed, trim the mainsheet and bring in the traveler to the extent you can without introducing too much weather helm. On my boat I would almost certainly have to heave to and take another reef in the main. Last summer on a feisty day on the Strait of Juan de Fuca, I experienced just this situation in 25-30 knots of wind, rounding Ediz Hook on the way in to Port Angeles. I had just read a magazine article on this point and used this approach to round the Hook. I believe it saved me from a knockdown. I look forward to some more discussion on this. 10. The correct answer is d. An upside down national flag is not a Coast Guard approved daytime distress signal. 52% got this right. Interesting that such a widely recognized signal is not approved. Source is The Annapolis Book of Seamanship. As always, I hope you had fun with this and maybe learned something.
 
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Royce

I understand #9 better now

I have to admit that I had some serious questions about #9's answer, but after reading this, it makes sense. You should post this on the other boards. This was a great test, thanks. Royce
 
D

David Knauer

Question 9 Heave to

How do you heave to and take a reef in your main? The only way that I have ever heaved to was to come about by putting the helm down and leaving the jib sheet on the (new) windward side while balancing this with the main sheeted tight. If you were to take a reef at this time, you would have to release the main and then the boat would fall off to leeward and perhaps jibe if the jib was sheeted to windward. Do you mean come about and sail under jib alone while reefing the main?
 
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