10 seamanship secrets
Stand-alone Wk abbreviations, circled or bracketed. The abbreviation
Wk is shown along with the known or least-known depth. It’s best to avoid
this obstruction altogether if it’s enclosed by any type of circle.
Half-hull symbols. Avoid these dangerous wrecks at all costs. Part of the
hull is always visible. At high tide, however, only the top of the mast, cabin,
or gunwale might show above the water.
“Fishbone” symbols enclosed by dotted circles. Stay away from these
wrecks. Uncertain depths cover the hulk during all tidal stages. When accom-
panied by the word Masts, some portion of a mast or masts—but not the hull or
superstructure—is visible above chart datum.
“Fishbone” symbols without dotted circles. Th is is the one and only wreck
symbol safe to lay your course across and is usually found in deep water.
Chartmakers plot these for the benefi t of commercial fi shermen (whose nets
might snag) or to warn larger ships not to anchor near such foul ground.
OBSTRUCTIONS
Stakes, spoils, beds, traps, nets, stumps, posts, and piles provide the sailor
with the same challenges as a slalom racecourse. Hazards such as underwater
pilings, deadheads (floating logs or trees), and submerged stumps plot as
small enclosed circles. Circles with dotted boundaries and numbers inside
show the least depth over the obstruction at all tidal stages. The abbreviation
Obstn complements many smaller obstructions.
Fish stakes, traps, or nets. Dashed magenta (light purple) lines mark the
boundaries of fi sh-stake or fi sh-trap areas. Th ese wooden stakes with underwater
nets strung between them proliferate in areas such as the Chesapeake Bay, where
fi shermen use them for catching baitfi sh. Sometimes you’ll fi nd the words Fish Traps
Dangerous wrecks include half hulls and fi shbones surrounded by a dotted circle.