We've been discussing electrical systems and how they work. As a result of a long discussion about echo chargers on www.catalinaowners.com (here: http://forums.catalina.sailboatowners.com/showthread.php?t=105813) an associated thread asked about how to find easy-to-use software for drawing wiring diagrams.
The link provided was in this thread: http://forums.catalina.sailboatowners.com/showthread.php?t=105866
It's called "Tiny Cad," see: http://tinycad.sourceforge.net/
I haven't used it myself and don't vouch for the "easy to use" part. :D
I used the "DRAW" feature of Microsoft Word to make my wiring diagram. Craig used Visio.
Craig's is Reply #14 here: http://c34.org/bbs/index.php/topic,4787.0.html
Mine is Reply #23, here: http://c34.org/bbs/index.php/topic,4623.15.html
I use Visio for all my work drawings, it's part of the Microsoft Office program and it's very easy to use. Files can be opened on any computer that has Visio installed. You create a background in several sizes with all your drawing block information then create a foreground overlay drawing size according to the circuit you want to do.
I used Visio, then saved it as a JPG. You can download a free copy of Visio viewer from Microsoft. We've used Visio at work for our network diagrams since before they were absorbed by Microsoft. I'm not the artist with it compared to my co-worker.
It's not as automatic as some of the other programs, but PowerPoint can also be used.
The co.com thread has been updated. Try this: http://forums.catalina.sailboatowners.com/showthread.php?p=610701#post610701
WHY WIRING DIAGRAMS ARE A REALLY GOOD IDEA
Just before I broke my leg skiing in January, I'd installed a nifty powered subwoofer for our stereo system in the saloon. After four months I finally got down to the boat again, but the brand new subwoofer wasn't working!!! So I dedicated a day to troubleshooting, checked voltages, nada, finally opened the back of the electrical panel and traced the wires. I'd gotten REALLY creative and had tied the subwoofer to the (shower) sump pump switch!!! Why? I'd figured that when I was topsides I didn't need the subwoofer down below, and it was "kinda cute" to be able to turn it on and off to hear the difference! Smart? You betcha! Dumb? Yup, I didn't do a wiring diagram nor finish noting that's how I'd wired it!!! And after four months, no way I'd ever have remembered that little brain gem, right? (I also hadn't intended to do a number on my leg right after I installed the subwoofer, either... :cry4`)
Just came across this: http://www.diagram.ly/
WORD draw is pretty much the same.