I have seen Tornados right themselves.. *shrugs*.. kittys fully airborne...

Yes in general there is a lot of property damage when those storm fronts come through.. Lost roofs.. demolished houses.. Flattened fences and trees...
On a river there is no swell just chop.. Foam capped chop with froth on the lee beaches..

Remember these are peak gusts... Not continuous as in a cyclone... But the damage can be considerable neverless..

As for the boat.. do your research on VJs.. *s*...