If you are cruising:

While in Mexico through to Panama I rigged up two fishing lines
strung to cloths pins around both sides of the boat. If the line was pulled
the end of it was a wooden piece of cloths pin that separated two screw contacts
in another cloths pin. Pull the stick out and the contacts (small bolts )
touch. On the back of the screws were connected wires to the bildge alarm.

It worked great, including the night in Punta Arenas Costa Rica when I came
back and forgot to step over it and woke everone on the boat.
----------

The other is a small yap yap dog. I hate em, but they are not electronic
and their batteries don't fail. When buddy boating they also yap when
someone approaches another boat. The potty problem is solved by getting a
chunk of hemp rope and coiling it on the deck. Dog does it's thing and then
throw the rope over to be washed by the sea.

I am sure there are a bunch of electronic stuff. But knowing electronics,
if it can fail it will fail. One year in the Long Beach CA to La Paz Mex.
race. One Hour after the gun went off, the sum log, and wind indicator.
We DR'd the coast of Baja in a fog for the race. This was long before
GPS, all I could use was sextant.

I skipper charter boats in the carib now. GPS is so amazing.

Gary










Peggie Hall wrote in message ...
Panama wrote:
I'm looking for design ideas and components for an intrusion alarm for
the boat. A friend bought 2 IR xmit and 2 IR receiver units to mount
in the cockpit, but my thought is that irregular sunlight bouncing off
waves, etc is going to set this arrangement off.

Thieves and vandals prefer the cover of darkness, making a motion sensor
light the most effective deterrent. Break the beam, the boat is flooded
with it. Higher end motion sensors can be adjusted for the amount of
"bulk" required to break the beam, which would prevent birds and flying
insects from setting 'em off.