Read what Knotstick owners say. The force is generally 5 to 7 ounces with a maximum of 12 ounces. You get an absolutely steady reading in all sea conditions. This is acheived through the use of a special dacron-neoprene tow line. Each spring is individually sized and checked to assure a permanent accuracy to within 0.2 knots.
All parts are uv resistant plastic or stainless steel.
Boat yards use Knotstick to calibrate electronic knotmeters. Knotstick comes with a no questions money back offer. Try it for 30 days and if you don't like it send it back for a refund. We gaurantee the read head for 1 year. If it fails send it back and we will repair or replace it free.