A high/low table answers a water-height question, not a current-speed question.
Two different planning questions
Tide height concerns the vertical position of the water surface. Current concerns water movement. A low-water time can be relevant to an overhead-clearance question while still leaving the handling conditions unresolved. Keep “when is the water lower?” and “what current should I expect?” as separate entries in your planning notes, with a source chosen for each question.
Do not use a universal timing shortcut
NOAA’s FAQ explains that the relationship between high/low water and slack or maximum current is not simple. The timing relationship varies with local conditions and the type of tidal current. Consequently, moving an arrival to a listed low tide is not evidence that the current will be weak or reversing at that moment. A convenient fixed time offset should not be transferred between different locations.
Worked example: two independent checks
Imagine a high/low table lists low water at 09:40. That gives you a candidate time to investigate, not a complete passage window. Record the tide station and reference first. Then consult the applicable current information for the passage and independently check bridge operation and weather. If one source is unavailable, the combined plan is incomplete even though the tide table contains a precise time. No current value is inferred in this example.
Check that the source answers your location
A tide station selected by a familiar city name may not be the appropriate reference for the particular crossing. Similarly, a current station can describe a specific location or depth rather than the entire route. Review the official station information and relevant chart. Do not interpret the absence of a nearby current station in our station finder as evidence of no current; this finder is designed around its advertised tide-prediction and air-gap products.
Use the planner as one layer
BoatWaypoint’s high/low output preserves the product’s datum and time-zone labels. It does not model current, vessel handling or bridge openings, and the intervals between listed highs and lows are not certified navigable windows. Carry the useful tide reference into the checklist, leave the current and operating checks visibly separate, and retain a waiting or alternative-plan note. The final decision remains outside the arithmetic in a tide table.
Read the high/low tide table
Keep the inputs, source references and unresolved dependencies together.
Read the high/low tide table