Originally Posted by ag3dw
Read a trip report on another site and found a different use of the term boat scouting. To me, bs means that I can see a clear route to the next two eddies (or one I know absolutely that I can make) where I can get out and bank scout or portage the rest of the rapid that I can not see. Or some rock or island from which I can absolutely ferry back to the bank. If that is at the top or part way down doesn't make a diff, "when in doubt, eddy out".
My definition of boat scouting is that you're scouting entirely from your boat. It's always a good idea to not catch that last chance eddy or to at least make sure you can get to shore and portage from your next eddy if you don't like what you see.
When running class IV, I'll do my best to boat scout as much as I can, especially on a long run where time savings is critical. Sometimes, I'll catch an eddy on the opposite side of the channel I think I want to run. That lets me peek at the runout easier and get an angle to look at the base of the drop if it's not too steep. When I can't see the base of the drop from my boat, I get out and scout. If it's difficult for the abilities of the others in my group, I'll recommend they scout as well. If it's not too bad, I'll relay the line, run it, and set safety for them below.
There are no hard and fast rules. If I'm not on a popular run, like the Green Narrows, and/or don't have a good leader in front of me, I err on the side of caution. That being said, you'd be surprised how much whitewater is boat scoutable if you try. Just make sure you leave yourself and your group an out and scout on foot if you can't see what you're about to run.