Only comment I would make is that the bent tabs on the bottom section are sticking out and could catch on something or collect salt, gravel, etc. To fix that, you could unbend it a little and then have the middle section tabs go over the bottom section tabs, like fish scales. This would ensure that the open edge is "down stream" of anything you might hit and would allow any water, salt, sand, etc to flow over the bottom tab.
I also second blame's suggestion to drill a few more holes for drainage, maybe a couple on the side tabs as well to attach some more metal ties.
I like it though, looks good, if my DP was wrapped I would definitely do something similar.