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Sunday, April 6, 2014

Bumpy Tide Chart Education

anchoring cruising life cruising destinations
Jacobs Bay Cove, Great Guana, Exumas, Bahamas.  
We had the beach and the whole cove all to ourselves.
Low tides are great fun for exploring tidal flats, by foot. They are not so great for you’re anchoring your boat someplace shallow, like we were in this instance....  

Seeking privacy after Black Point’s cruiser crowds, we decided to mosey slowly to Georgetown.  Along the way, we planned on seeking at least one anchorage we’d have all to ourselves.

Pretty little Jacobs Bay Cove fit the bill, perfectly.  Even motoring, with the wind in our face, it was an easy hop, just a few miles from BlackPoint. We could tell from a ways back, we’d have the anchorage with a sweet little beach cove all to ourselves. 

anchoring cruising life cruising destinations
Buoy head on Great Guana beach; another beach equivalent
of a snowman or snow woman it seems in this case.
We anchored close in, in 7-8’ of water at high tide.  Our boat drafts 4 ½’ though we prefer not to test its limits too much, especially not in the dark.  No worries, we figured, the tidal swing was minimal that night.

The sun was shining.  We enjoyed an afternoon swim, a nice supper, sunset, then a gradual wind-down for the eve.

Until 7:30 pm.  Dark.  Bump.  Bump BUMP. BUMP. BUMP BUMP. BUMP BUMP BUMP….


cruising life cruising destinations
Wayne wearing his favorite wading suit at Jacobs Bay Cove,
a secluded beach on Great Guana, Exumas, Bahamas.
We recognized the sound and felt the jolt of our hull hitting the bay’s sandy bottom, not damaging our hull, but scraping our scant ablative paint and annoying as heck.  We discovered we were now in 4 ½ - 5’ of water, hitting each time we were in a wave's trough.  In the darkness, we pulled our anchor’s bridle and anchor up, and moved further out and deeper in 10’ of water.  This time, we were anchoring in low tide, and knew it wouldn’t get any lower than it already was when we dropped anchor.  We anchored in 10.' We stopped bumping.

Curious, we reviewed the “minimal tidal swing” charts and realized the Excel spreadsheet we’d transferred the data onto (for non-internet reference) had wrapped its cells a bit.  As a result, there was a minus sign that we missed in front of the day’s tidal forecast.  That means what we thought was not such a low tide, was actually a tide so low it garnered a “minus” or “negative” tidemuch lower than “normal.”  That night, it was about a 3’ drop; enough to get us into trouble!

cruising destinations anchoring near blackpoint
Notice the minus sign (“-“) on Monday April 7th of this tide table? 
That’s what it was like Feb 22nd… ony we didn’t notice
the minus sign.  Minus = lower than usual tide!
This was a relatively gentle lesson based on Jacobs Bay Cove’s sandy bottom, but a good one to pay attention to going forward.

Location Location

April 6, 2014, BAHAMAS.  This is a retrospective to February 22, 2014 at Jacob’s Bay Cove (N24.03.360 w76.22.588 – before or after we moved? dunno).  It was written and pre-posted from the Raggeds Hog Cay near Duncantown, while waiting for Southerly winds to make a sail to Long Island’s Eastern shore, then to Rum Cay, Conception, San Salvador, Cat, Eleuthra and Abacos.  Latest plan is to leave the day this posts, taking an overnight passage as the sail is 60+ miles and requires navigating shallows at higher tides and arriving in Long Island in daylight.