water speed, depth guage

Can you get or is there any recommendations for some devices that would give you depth and or water speed readouts? Any other devices out there that are useful?

I am a guage junkie. If I can't race against someone, I have to guage (pun intended) my progress somehow.

Would they be too fragile for a h14? ie the probes getting trashed by rocks etc?

I sail in a resevoir that has a few rocky shoals here and there and I have no idea of the location of all the shoals as I am the only sailboat around.

Well if you really want all the bits and pieces for this boat i do have a suggestion. Dont sail it. I dont know of many guages which are water proof and if your going to race well i dont think its race legal to have one on. Dont see why but all of this is true.