Thats a very good question leftcoast, the few things i would say are, lakes with lots of fishing pressure like near boat ramps the fish that locate here and rarely leave are used to boat traffic and noise. I was watching a fishing show it might of been doug hannon who said this i'm not sure but, they would leave the electric motor on low while fishing in shallow water rather then turning it off, the constant turning on and off makes its more obvious i guess and the fish pick up on this. l personally believe the clearer the water the more bass notice with sight and also therefore locate better with the other senses such as hearing with a noise where its coming from. One thing that some people still get confused with is they say loud talking and screaming is bad because the bass can hear these sounds. To this day my friends dad says this to us all the time and thats in fact not true. As long as your not causing major vibrations like dropping tackle boxes or an anchor on the bottom of your boat then your all good. Lastly if you think you have upset the bass because of load noise, just back off of the area and come back 10 or 15 minutes later, its the same as a honey hole situation, i just learned this from another fishing show recently, rather than catching a few and having them signal the rest of the fish that somethings wrong, back off of the area for sometime, come back a little later on and enjoy the slaying once again!!!