A few weeks ago somebody asked for a cheap alternative knotmeter. Someone mentioned a KnotStick - (speed is gauged by pulling a weighted disk). I looked at the website and decided to buy one. The price was very good and if it didn't work I wasn't losing much. I have used it twice in great sailing weather and I must admit it is great to have something to guage speed. I am not sure how acurate it is. I have an O'Day 25 and close-hauled I was "doing" between 5-6.5 knots in 12-15mph wind gusting to 20mph. The only downside is the line pulling the disk extends about 20 feet behind the boat - looks like I am fishing.
KnotStick
- Thread starter Scott R21226
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W
Wayne
Boat speed
Scott I have never heard of a knot stick, its sounds very interesting. I have a C380 and I never quite know how fast I'm going. I have a GPS and a Knot meter and they never agree with each other. I have tried to calibrate the gauge to the GPS but they always a little diferent. I can only assume that this is effected by the currents. The only true way to calibrate your speed is by motoring between two known points and take note of the time taken. Good luck.
Scott I have never heard of a knot stick, its sounds very interesting. I have a C380 and I never quite know how fast I'm going. I have a GPS and a Knot meter and they never agree with each other. I have tried to calibrate the gauge to the GPS but they always a little diferent. I can only assume that this is effected by the currents. The only true way to calibrate your speed is by motoring between two known points and take note of the time taken. Good luck.
D
Don
I have used one for years. Cheap, simple and very accurate. Eventually, the bungee line will lose it's stretch. I found replacement line at a fabric store for pennies.
Shouldn't calibrate the speedo to the GPS.
They are measuring different things. Speed over ground, and speed over water.
They are measuring different things. Speed over ground, and speed over water.
Everyone remain calm, I'll give Wayne the
short answer. GPS gives your "Speed Over Ground" (SOG), Knotmeter is "Speed Thru Water" (STW) when going with the current your SOG is STW + current speed, against the current your SOG is your STW minus current speed.
short answer. GPS gives your "Speed Over Ground" (SOG), Knotmeter is "Speed Thru Water" (STW) when going with the current your SOG is STW + current speed, against the current your SOG is your STW minus current speed.
Sorry everyone, I take it back. *x
I didn't realize what I had done. Sorry everyone. I take it back. I take it all back. I didn't say anything.... I didn't mean to get it started again. *x *x
I didn't realize what I had done. Sorry everyone. I take it back. I take it all back. I didn't say anything.... I didn't mean to get it started again. *x *x
S
Steve LeBlanc
L
Lloyd
not to be knoty but
how can i find out my max hull speed and what wind and tack would it best be found ?(novice)
how can i find out my max hull speed and what wind and tack would it best be found ?(novice)
R
Randy
1.34 * SQRT LWL
For normally proportioned displacement hulls (most keel sailboats) the "hull speed" is the square root of the waterline length times 1.34. For a Cat 30 with a 25 foot waterline it is: SQRT 25 (5) * 1.34 = 6.7 knots With enough wind you can reach hull speed on almost any point of sail (not close hauled).
For normally proportioned displacement hulls (most keel sailboats) the "hull speed" is the square root of the waterline length times 1.34. For a Cat 30 with a 25 foot waterline it is: SQRT 25 (5) * 1.34 = 6.7 knots With enough wind you can reach hull speed on almost any point of sail (not close hauled).
T
tom
I have a knot meter
It doesn't give accurate numbers much of the time. A little piece of weed or string or whatever will affect the indicated speed. I even had a barnacle grow on one of the paddles. I use it as a reference to judge performance. Cleaning the paddle wheel can be a real pain as water gushes into the boat until I stick a wooden cone into the hole. When I want to estimate my time and bearing to a destination I use the GPS. The GPS automatically compensates for currents,leeway etc.
It doesn't give accurate numbers much of the time. A little piece of weed or string or whatever will affect the indicated speed. I even had a barnacle grow on one of the paddles. I use it as a reference to judge performance. Cleaning the paddle wheel can be a real pain as water gushes into the boat until I stick a wooden cone into the hole. When I want to estimate my time and bearing to a destination I use the GPS. The GPS automatically compensates for currents,leeway etc.
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