VB and all
Praying it will miss ya! IN my humble opinion 1/2 mile is not enough room. Irene is forecasted to be a major hurricane, I think a lot of water
is going to come up that river ( big storm surge) BUT I would find some old sea salt
in your area, dink over to the guy tying up to the trees and in the hurricane hole and talk about what happened last storm. Gleen local knowledge, You may hear that the river is not your best chance. What about that marina? Is it a good one? Floating docks with tall pilings for high storm surge?
Sorry I couldn't give you Any real local knowledge but a 1/2 mile is nothing in a major storm( IMHO ).
Good luck, we will be praying for you and your vessel.