Fathoms, Feet, F****, there's no depth here

The marina in Key Largo is on the Port Largo canal.  The Port Largo canal in turns opens up to what is still part of the John Pennekamp State Park, this means, no dredging the entrance.  So while in the canal you have MLLW of 18 ft, it rapidly (as in 5 seconds) goes to MLLW of 4.5-5 feet (depending on who you ask).  It can be very unnerving. Now, if your keel offset has been reset to zero (meaning it's reading from it's location at the bottom of the hull and not offset from the bottom of the keel), you are really going
to have a sphincter moment.  Thankfully after looking at the charts and tidal situation and doing some quick math. Chart + Tide - Approximate keel length (should) = what the depth guage is reading. It was. And we must have been correct because we never ran aground.

So we took her for a quick spin in Hawk Channel and the old girl was happy to be back at sea.

On a side people suck rant here, it is common courtesy because of the narrow entance and shallow depth to announce your departure/arrive through the jetty with a Securite call. You should also announce your outbound/inbound at the canal corner affectionally called crash corner.  We were leaving and three huge fishing boats come in, did not annouce. RUDE!