As part of the recent string of messages concerning the sagging utility lines over the primary entrance to Boot Key Harbor (see /?p=84015), a side discussion has come about concerning depths on Sister Creek. The “primary” entrance to Boot Key Harbor (“BKH”) is a more or less straight shot from Moser Channel. This is the passage over which the sagging utility lines cross.
Sister Creek is an alternate entrance to BKH, which runs, more or less, north from Hawk Channel. In the “sagging utility lines posting,” both yours truly and our very special Florida Keys correspondent, Captain Charmaine Smith Ladd, cautioned that boats drawing more than 4 feet should not attempt to use Sister Creek to access BKH. This admonition resulted in some dissenting points of view:

Click Chartlet Above to Open a Chart View Page Centered on the Entrance to Boot Key Harbor

Good to hear the alert but Sister’s Creek is deeper than 4′. I have come in and out of Boot Key via Sister’s Creek and have never experienced less than 6′. Take your own chances ‘“ I’m just saying.
Always FOR SAIL too

I disagree about Sister Creek ‘“ large sportfishers and sailing craft enter the harbor from Sister Creek daily. There is a spot at the entrance that might preclude 6’ from entering at MLW, but half tide and rising there is no apparent problem. I am anchored on Sister Creek with two other craft as I write this.
Peter TenHaagen

So, I asked Captain Charmine to comment further on the soundings to be expected in Sister Creek. Here is her reply:

Regarding SISTER CREEK. Sister Creek at mean low tide is 4’1’³. That’s FOUR FEET ONE INCH. From that point, as usual, you have to do the math with the tides as far as one’s draft is concerned. Obviously if you have a two foot tide you’ll be fine if you draw less than six feet. With that said, whatever someone has experienced in their vessel is highly subjective and there are dangerously hard groundings that occur in Sister Creek because of this. Each Captain has to make his or her decision based on their particular situation.
This is why I am extremely cautious with suggesting using Sister Creek to others. Some don’t watch tides as closely as others. Therefore, I merely report its mean low tide depth. Those who traverse Sister Creek with 6′ drafts have done their homework’¦and that is all that is necessary in order to decide to use it or not. Just know that it is not quite a no-brainer unless you have a shallower draft vessel.
Hugs!
Charmaine

Remember if you enter Sister Creek from Hawk Channel, it’s a normal red-right-returning as you enter Boot Key Harbor.But the channel colors `reverse’ where Sister Creek meets Boot Key Harbor. That’s because the markers near that entrance are really a continuation of the markers from the main entrance channel at Seven Mile Bridge, and thus are `reverse-colors’ from the Sister Creek entrance. That can cause confusion and potential grounding if the skipper is on the `wrong’ side of the markers as they enter Boot Key Harbor where the water at that intersection is shallow.
Joe Curley

I agree with Captain Charmaine. Our boat draws 4 feet and our depth sounder is accurate to within 2 inches. We departed Sister Creek in February of 2012 at dead low tide and our depth reading was 4 feet. Sister Creek itself is deep enough. The shallow area is east of the entrance to Sister Creek between the Red and Green marks.
James Angel

We recently entered Boot Key via Sister’screek in our sailboat. It was at mid tide. Our dept sounder is set for actual water depth and is accurate. We saw readings or 4.1 on the sounder. The draft on our boat is 5 foot but we never even felt a bump let alone run hard aground. I wonder if there is a heavy grass growth that may be bouncing the echoe sound up from the tall grass. This occurred just off the beach in the channel. The rest of the way was all over 5 foot or better
Capt. Mike

I just returned in my dinghy from the marked channel entering Sister Creek from Hawk Channel ‘“ I found at dead low tide some 4.5′ spots between markers 2 and 3/4, nothing under 5′ after that and nothing under 7′ once past the marked channel. I don’t know the exact tide range but it is well over 2’ ‘“ I would say 3-4′ depending on winds and other conditions that affect the tide. I did this for friends in a 5′ draft sailboat planning to meet me here over the weekend.
Peter TenHaagen

Boat using sister creek this morning reported at least 6′ at near high tide. Local knowledge is needed as there are shallow rocks reported to be inside one of the red markers. Local boat US will charge $400 to escort you thru.
Ted

For the past 12 years I have lived on Sombrero Blvd. For the first 5ive years I had a Shannon 43 drawing when cruising 5′ 2’³ that I took in and out of Sisters Creek. I have read the warnings and looked at the charts but have yet to run aground. My neighbor had a Gulfstar 50 that he took in and out numerous times. He did bump once or twice but never ran aground. I took my boat in and out regardless of the tide level although never at a low low tide.
Joe Hamrick

Re Sisters Creek: I lived in Marathon for 11 years, and always used the Sisters channel coming and going on my 50′ Gulfstar with 5.5′ draft. I recall a light bumping once or twice during very low tides, but most locals consider the channel good for 6′ in normal high tides.
The old charts do say 4’ at MLT, but local knowledge is pretty well established on this one.
Ed Loke