i am always tinkering. two of the most usefull things i made were a furling system for my prindle 16 that cost less than $100 for the whole thing installed. it works great andthe other thing is a sail timer, but not just a plain sail timer. i have a garmin gpsmap 176 that i use when i race on monohulls. it has just about everything except a countdown timer. it has the capability of displaying water temperature if receiving data from a nmea device. the timer i built outputs the remaining time and all other numbers to be displayed on the nmea temperature sentence. it has only a power switch and one button. pressing and holding the button places it in set mode. it counts up by minutes incrementing every second. after you let the button go, it waits for another press of the button to begin the countdown. the time is displayed on the gps display.

if you like that, it gets better. after the race starts it changes mode and becomes a tactical compass. it reads the heading from the gps and compares it to the heading it was at when you pressed the button (you set the starting heading each time you tack by pressing the button). it subtracts the starting heading from the current heading, does some math to determine if there is a head or lift and displays the angle in positive or negative degrees. when you mark the starting heading for the tack it samples the heading for 5 seconds and then averages the headings over the 5 seconds to take into account any quick adjustments the skipper makes to the heading at the beginning of the tack.

i built the timer/compass for about $70. it is a small microcomputer in a case that is about 3" x 2" x 3/4" with the button and power switch in the case. it could easily be smaller and have a remote button or buttons without much modification.

i figure when i buy my monohull (i'll also keep the prindle) i can mount it below with the other instruments and have a remote button in the **** area for racing.