When you enter the main channel to the fort,
it is from north to south, it is pretty deep but stay in the middle
of the channel markers.
When you come to the channel that turns west to go to the fort anchorage,
turn from the middle of the north channel (90 degrees) to the middle of the channel that goes west.
If you cut over by that red sign it will get a little shallow and your bottom machine will turn bright red.
It comes up all at once and you will have a heart attack.
Other than you will be good to go.
Oops, meant that to be IM.