No gps

[jleblanc31]

I don't have a GPS to tell how fast I am going any ideas on a not counter? Ive heard of using a line with some nots in it but haven't heard of any specifics on length or how far to space the nots to get an accurate reading or close to accurate reading. I don't even know if this is just something some one made up or if this was actually used but i like the nostalgic stuff Like how starboard and port came about. So if you know about the nots thing or know of a good website on stuff like this let me know .It seems to me that these things are falling buy the waste side with technology and the living encyclopedias are slowly disappearing ,and with them this knowledge.

 

[kevin]

knots per hour

In days of yore, a log tied to the end of a rope was thrown overboard. This rope had knots tied 47' 3" apart. A 28 second hour glass was then used for timing. At the last grain of sand falling, the number of knots that went through the counters hand was the speed.Read that in a book a long time ago. I wrote it down so as not to forget, for just such occasions. Granted this is for speed through the water and not across the ground.I am sure there is a math wizard that could determine the formula between 6000' in a nautical mile and 28 seconds and 47' 3". Me, I'll take it as truth, until proven otherwise.

 

[Jenni]

A log

In Nelson's time they would throw a log with a rope attached to measure speed I found this entery in Wickapedia about it.A chip log is a navigational tool used by mariners to determine speed through the water - a combination of speed over ground and the effect of water current. A chip log, literally consisted of a piece of wood. The rope tied to the log had a number of measured knots tied in it. The speed of the ship was indicated by the number of knots passing over the stern during a certain period of time. The unit, knot, for nautical mile per hour, was derived from the knots tied in the rope of a log.A chip log consists of a piece of wood, most often cut in the shape of a quarter circle, or "quadrangle", and a length of rope or line with knots tied every 47 feet and 3 inches (14.4 meters). To determine a ship's speed, the chip log would be placed into the water aft of the ship, line payed out, and the number of knots payed out in 28 seconds counted, giving the speed in knots. A number of considerations had to be taken into account -- the amount of following sea, stretch of the line, and inaccuracies in the measurement of 30 elapsed seconds. Time passage was most often marked with a "30 second glass", a small sand filled glass, which would often run fast or slow based on ambient temperature, humidity, and sea state. Frequent measurements helped in mitigating some of these inaccuracies by averaging out individual errors, and experienced navigators could determine their speed through the water with a fair degree of accuracy. Mechanical chip logs, operating on physical principles in a manner similar to a car's odometer, were eventually developed and replaced the traditional chip log.

 

[kevin]

Wow

Ow bout that, I was right!!!!! Hurry someone take a picture of this!!!

 

[Malcolm Young]

Orange Peel Log

Not sure this is environmentally correct in 2007, however in the late 70's I took an on the water cruising course before moving from sailing dinghies to a cruising boat. The instructors 32' boat just had a compass. He had been a aircraft navigator during WWII (although this has nothing to do with the orange peel log but something to do with his credibiity).We navigated using the compass and the orangepeel log. It works like this - you accurately measure the distance on your boat between two distant and clearly defined places - eg. The place the top lifelines joins the bow pulpit to the place the top lifeline joins the stern pulpit. One person drops a little bit of orange peel in the water at the bow location and and a second person uses a stop watch to time it until it passes the stern location. A simple distance over time calculation gets you the speed. To make life easier you can transfer a series of calculations for different times to a graph and once you have the time for travelling the distance, you simply read off the speed.We navigated the whole week using the compass and the chip (orange peel) log to calculate how many knots we were going and used this to calculate distance travelled. We were quite accurate in our naviagation. This is something I have filed away in my memory bank for the time that our electronics packs it in. However you do have to know basic navigation techniques and it is wise to have tides and currents tables if in tidal waters.

 

[sailaway78]

This will give you

The question is how close do you want to measure boat speed. The methods listed will certainly give you an indication of your boat speed. But thats about all they will do. Boat speed is constantly changing, and you would have to be pretty good with these kinds of log to get very close. It might be fun to experiment with one of these, but if you want to know how fast, or slow, your really going, or how far you have gone, trust modern technology. A pretty good hand held GPS now can be had for around 100 bucks.

 

[Calif. Ted]

Get something like this knotstick or

make your own out of an old fish scale.http://www.knotstick.com/index.htm

 

[jleblanc31]

Thanks

thanks, yall. I will be going out tomorow and I will try some of your ideas.