Who knows shutter speeds??

ryant35 wrote in post #5734342
Along with your depth of focus and shutter speed yes.

The reason for my shutter speed is that "I" was in another boat and I was rocking up and down heavily. I'm afraid that if I slowed my shutter down to 1/100 or so, it would have really been a disaster because the subject was flying by me while I was moving up and down, up and down, on the front bow of my boat, due to all the waves. I agree with the F5.6 was too shallow and yes, I think I did focus on the tube because their head was a tiny object to try and lock onto.

snyper77 wrote in post #5734433
The reason for my shutter speed is that "I" was in another boat and I was rocking up and down heavily. I'm afraid that if I slowed my shutter down to 1/100 or so, it would have really been a disaster because the subject was flying by me while I was moving up and down, up and down, on the front bow of my boat, due to all the waves. I agree with the F5.6 was too shallow and yes, I think I did focus on the tube because their head was a tiny object to try and lock onto.

Consider this a learning experience then! Next time you go out you'll have a better idea of how to handle this type of situation!
Just in case you aren't sure, when in AI Servo focus mode the camera will constantly try to focus on whatever point you have selected. Because its focusing constantly there is no "Focus Confirmation" beep or light in the viewfinder. But if you can hear the focus motor making slight adjustments and not searching than you can trust that the camera is focused.