Sure, a good worry to have, but there is nothing that I know of specific to a Hobie that isn't a shared worry with all kayaks and vessels. If you hit a stump, it isn't pleasant with or without a propulsion unit of any sort. I think Hobies generally have a solid reputation for handling stumps and vegetation very well.
In my Slayer Propel, I have to watch out for vegetation more so than a Hobie would as it can gum up, wind itself up actually, around the propeller. But, what I can do, haven't had to yet, is release the hold down clip that fixes the propeller unit into a down position so if I did run into a stump, the Propel unit would lift up and not take the full brunt of the impact. Some Propel operators never lock down the lower clip and it has little effect of its operation.
There may be a similar "work-around" for a Hobie and I'd definitely check out the Hobie Discussion Board to see what others might be doing.
I'd go a bit slower, too, if you know you are moving across a stump field. If you are on Fork, with all the boat out there most of the time, the last thing you want to do is avoid the stumps by scooting along in the boat lanes.
Edited by Brad R (10/08/15 06:52 AM)