> Gee I should have know that after all I'm an engineer :)

> Thaks for reminding about the hall effect. I was actually more concerned
> about melting the dumb thing. I guess an LED would be bright enough.

> How about a fiber optic run from the running lights?

If you can afford the materials then fiber optic materials are great. Consider this, though: you have probably got enough glass fiber material, in the form of scraps from the fiberglass cloth you used for your hull, to light a dozen kayaks. Has anybody tried converting some of this scrap into cheap light guides?

I don't expect to get high efficiency, like that needed for a telephone network, but I should think that for a length of 3 to 4 meters the light transmission properties would be pretty good.

If anyone wants to try this, let me suggest an experiment. Get a piece of heat-shrink tubing. Cut a strip of glass cloth about an inch wide, and 2 inches longer than the tubing. (those who use light weight cloth may need to get two or three strips, each 1 inch wide.) Separate the fibers that run the length of this strip, and group them. Discard the 1 inch cross strands. If you try using wider material it may be harder to separate the long strands.

Wrap a standard sewing thread several times, tightly, around one end of the group of long strands to secure them. Drop the sewing thread through the heat-shrink tubing, and use it to pull the glass fibers into the tubing. If you have difficulty getting the thread through a long piece of the tubing, a few gentle puffs of air may ehlp to move it along. With the glass fibers in the tubing, heat it up so that it shrinks tightly around them, and secures them in place. That should work as a light pipe, at a fraction of the cost of comercial fiberoptic materials. Heating the end of this with a blowtorch might heat polish the ends, but it would probably also burn the heat-shrink tubing. Instead, put a single drop of epoxy on each end. If you are planning to put an LED on one end, now is the time to do it. The real problem with light guides is that you rely on a single bulb to illuminate everything. If you go this route, then should your running light bulb burn out, you have neither running lights nor a compass light. Hopefully you'll have a spare flashlight.

If you are running off of a 12 volt power supply: An array of 6 LEDs wired in series gives a lot of light, can be shoved into a length of clear vinyl tubing, and eliminated the need for finding a resistor to drop the voltage.

Rechargeable, or alkaline flashlight batteries of most any size can be put into an appropriately sized section of PVC pipe -- which is easily waterproofed. A brass bolt through each endcap serves as a long lasting terminal. Plenty of conventional hardware around for easily mounting such a battery tube.

Hope these ideas encourage someone Paul Jacobson