They are 'supported' by the rubber grommet in the Cable Clam (see the links above) and then held in place by a p-clip outside the mast. Here's a good shot of that:
http://www.flickr.com/photos/deeppla...7622793614824/
The original 30 year old wiring was held in place with a knot and some 4200 for the most part. In some places there was a passthru similar to this one:
http://www.shakespeare-marine.com/co...?menupick=4184
The cable clams surpass those IMHO.
-p