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Current Tables: Reading the Traditional Format
Current Tables: Reading the Traditional Format – Mariner Studio Current Tables: Reading the Traditional Format I learned to read current tables the hard way—standing on the bridge of a 190-foot vessel, watching my fuel consumption climb as we pushed against 3.2 knots of ebb in Deception Pass. The chief engineer appeared beside me, pointed at
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Using Current Data for Fuel Efficiency: Save Fuel by Working with the Flow
The fuel gauge dropped another quarter tank in just three hours. We were running at our normal cruising speed, making the same run we’d done dozens of times before, but today we were fighting a 2.5-knot ebb current the entire way. By the time we reached our destination, I’d burned nearly 40% more fuel than
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Current predictions vs observations: Understanding the gap
You’re approaching a notorious current station where predictions call for 1.8 knots of ebb at your arrival time. Your route takes you directly through the channel, and at your vessel’s 8-knot cruising speed, you’ve calculated a comfortable transit. But when you arrive, the GPS shows you’re making barely 5 knots over ground. The current isn’t
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Rotary currents: Understanding non-reversing tidal flows
Three miles offshore, the current meter showed 1.2 knots setting southwest. Six hours later, instead of reversing to northeast as expected, it had simply rotated to southeast at nearly the same speed. This wasn’t the familiar ebb-and-flood pattern we’d learned to anticipate—this was a rotary current, and it was teaching us that open water follows
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Ebb and Flood: Understanding Tidal Current Direction
I was standing on the bridge wing of our ATB watching the Delaware Bay buoys lean hard to the west. We were three hours past low tide, riding four knots of flood current up toward the C&D Canal, and I watched a southbound tug fighting that same current struggle to make even two knots over
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Current Stations: Real-Time Flow Monitoring
I watched a 40-foot sailboat get swept sideways through Deception Pass last summer. The skipper had checked the tide tables but ignored the current station data showing 6.8 knots of ebb. That oversight cost them three hours waiting for the next slack water window and probably a few years off their life expectancy. Current stations
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Diurnal vs Semi-Diurnal Tides: Regional Patterns
The tide station at San Francisco shows two high tides and two low tides every day, with roughly equal heights. Travel south to the Gulf of Mexico near Pensacola, and you’ll find only one high and one low tide per day. Head to Seattle, and you’ll encounter two daily tides—but with wildly different heights between
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Tide Predictions in Rivers and Estuaries: Navigation Guide
Tide predictions get complicated when you move inland from the coast. That morning high tide at the river mouth might not reach thirty miles upstream until afternoon. The twelve-foot range at the harbor entrance could drop to just four feet where you’re anchored. Understanding how tides behave in rivers and estuaries transforms navigation safety and
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Understanding Tidal Datums: MLLW, MLW, and Chart Depths
You’re planning a passage through a narrow channel. Your chart shows 8 feet of depth at the entrance. The tide table predicts 2.5 feet at your crossing time. Simple math says you have 10.5 feet—plenty for your 5-foot draft, right? Not necessarily. Those two numbers use different reference points. Understanding tidal datums transforms how you
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Bridge Clearance Planning with Tide Data
The tide gauge at the Charleston Bridge showed 4.2 feet above MLLW. The chart listed the bridge clearance as 65 feet at MHW. With our mast height of 62 feet, did we have clearance? The answer required understanding not just the numbers, but what they actually meant. Bridge clearance planning is one of the most