I think bass are very inquisitive creatures and they are aggressively territorial. I have snorkeled with bass and watched them for hours. Your immediate presence is a bit daunting for them, but they settle quickly and then want to come check you out. (see my article at
http://www.bassing.co.za)
Sharp quick movements with your arms do spook them a bit as well, but things like blowing hard into the water through your snorkel drain valve really attracts them, and they get quite agro. So the bubbles created by your motor could be an attractant whereas your boat itself will spook them a bit at first.
Look at Marlin fishing, your number one attractant is the wake created by your boat itself, only when the marlin gets closer does he notice the exciter birds, and last of all spots the conas / bait.
The other thing to consider when it comes to outboard motors, especially jetskis, is the fact that the thrust is creating bubbles in the water at the same time. Owners of Side Imagers will confirm this, because you can actually see the ‘bubbles’ on your screen where a boat has taken off.
I was trolling for bass at Inanda on my way from James Bay to Dusi point, and noticed this youngster going wild on his jetski right in front of the launch area. You can imagine what I was saying about jetskis as I was approaching this hooligan, but low and behold, as my lure went through this spot where he was doing donuts and things, I got hit by a really good bass (3.98kg’s). So bring it on jetskis! LOL