The box bottom has a lot of weight in it to hold it down in the float, so they're real tough to turn over. You've just got to be careful with the wind and waves when you're going to use it as they will fill up pretty quickly if the waves get bad. They won't sink or turn over, but the box itself will fill with water which ain't much fun by all accounts if you're inside when that happens.
There's a bailing can inside at all times. You just bail the water out when it starts to get near the height of the seat. The waves will come right in it if it's very choppy.
The only way to stay relatively dry is just to wear good rain gear and knee high boots. Some guys wear waders but I prefer just rain gear as it's so much easier to get around in. Getting in and out of these things isn't super easy and I'm a big man who's not super graceful so I need all the help I can get.
As far as gun protection goes, you can't worry over it really. Just give it a good drying out and oiling down once you get back home. My fowling pieces are all workers, they ain't just to look at.
Hopefully I'll be posting more pictures of mine in use this next season. Won't be sea ducks though, it will be canvasback and redhead if everything works out right.
Here's a picture I took while sitting down in the box. That wave had rolled up over the back deck and down my neck a second before.