Re: broken transducer
http://www.marinetex.com/PRODUCT PAGE_files/All MarineTex Putty/marinetex prod info.htm
marine-tex is a 2-part fiberglass putty - I use it to repair my hull like, for example when I ran aground one night on a gravel shore, or when the trailer was misadjusted & scraped the keel to heck. they have it at west marine and BPS, sometimes at academy. haven't checked at cabelas.
how effective it'd be for you might depend on where your break is
my transducer broke just below the bracket - other words, the upper part of the 'ducer was still in the bracket and the lower part was hanging by the cable. Super glue didn't hold it, epoxy didn't hold it (generic hardware-store 5-minute 2-part epoxy). then marine-tex applied just in the break, like you would use an adhesive, held for several months, eventually broke off (just from water pressure under way). So this time I wrapped it in a pretty thick layer of marine tex, a year later still holding strong.
as an aside - when I tried the epoxy, I let some of it run down on the face of the 'ducer, tried to clean it off with MEK, ended up with a knarly scored scratched 'ducer - worked ok going slow, but at speed it wouldn't draw the bottom contour although it did show the depth. I applied a thick layer of loctite 60-minute marine epoxy to the bottom - just drizzled it on and rotated it as it cured - did the trick!
good luck!