Sunday, November 1, 2020

Low Bridge, Low Water

I forgot to write about our experience passing under the Wilkinson Bridge as we made our way through the Alligator River-Pungo River Canal yesterday.

All the fixed bridges on the Intracoastal Waterway (ICW) have a minimum clearance of 65 ft at mean high water per Army Corps of Engineers specifications. Somehow the Wilkinson Bridge was constructed with a clearance of only 64 feet.

The top of Intermezzo's mast is 62 feet 8 inches above the waterline. The VHF radio antenna extends 18 inches above the top of the mast, which puts its tip at 64 feet 2 inches above the waterline. The water level gauge at the base of the bridge read barely 64 feet clearance. Sure enough, as we passed under the bridge- very, very slowly- the antenna bent as it brushed the underside of the bridge girders. 

I've never been that close before. I hope never to be so again.

Now we have a low water issue.

The high winds blowing from the northwest tonight are sucking the water out of the Pungo River and surrounding sounds. There is a low water advisory (something I've never heard of until now) as water depths are expected to fall far below normal in these non-tidal bodies of water. 

The marina reported that during the last storm like this, the depth of the water at the docks fell 2-3 feet. This storm is supposed to be worse.

The depth sounder showed 5.3 feet deep water where Intermezzo was originally tied up to the dock. We start touching bottom when the depth sounder reads 4.1 feet. So, if the water depth fell 3 feet during the storm, we would be sitting on the bottom. We moved the boat further up the dock where the depth sounder read 7.1 feet for a better chance of staying afloat. So far the water has fallen about six inches.

The bottom is soft and level, so it's not that big a deal if we end up aground. I just have to be aware of what's going on with the docklines and all is clear for when we re-float.

Sometimes the water is too high, sometimes it  is too low, sometimes it is just right.