Ocean-Current // Hydrographic & Drift Telemetry Portal

Visualizer Controls

Ocean basin Depth horizon Forecast horizon: +0h Layers

Current Vectors

Sea Surface Temp

Swell Height

Click any position on the chart to open its point telemetry. Speeds in knots, directions in degrees true (direction towards which the water flows).

POINT TELEMETRY

Inputs

Heading (°T, 0–359)STW (kn)Current Set (°T, 0–359)Current Drift (kn)Distance (NM)

Results

COG (°T)—

SOG (kn)—

Drift Angle (COG − HDG)—

Current Factor (kn)—

Passage time (HH:MM)—

ETA (UTC, from now)—

Current	Region	Mean (kn)	Peak (kn)	Direction	Temp (°C)	Navigational notes

UTC	HDG	STW	Set	Drift	Dist NM	COG	SOG	Drift ∠	Curr. factor	Time

The log is empty. Compute a passage in the Set & Drift / ETA tab and select Add to Voyage Log.

1. Scope

The portal supports passage planning by resolving the effect of surface and sub-surface currents on a vessel's track and speed. Output is advisory and does not replace official charts, sailing directions, navigational warnings or the Master's judgement.

2. Vector drift solution

Ground velocity is the vector sum of the water-referenced velocity (heading H, speed through water S) and the current vector (set σ, drift d):

Gx = S·sin H + d·sin σ Gy = S·cos H + d·cos σ
SOG = √(Gx² + Gy²) COG = atan2(Gx, Gy) mod 360
Drift angle = COG − H (normalised −180…+180, positive to starboard)
Current factor = SOG − S Passage time = D / SOG

3. Reference ocean data

Gridded products of the following classes inform the parameterisation of the current, temperature and swell fields: NOAA Real-Time Ocean Forecast System (RTOFS) global ocean fields; Copernicus Marine Service global physics analysis and forecast; GEBCO global bathymetry for coastline and depth context. Products are distributed as GRIB2 and NetCDF.

4. Visualizer model

The chart renders a parametric gyre-and-jet representation of the climatological circulation in each basin, scaled by depth horizon (surface 100%, 50 m 60%, 200 m 30%) and modulated over the 0–72 h forecast range. Sea surface temperature and swell layers are smooth regional estimates. Point values are indicative and must be confirmed against an official forecast before use in decision making.

5. Limitations

Mesoscale eddies, tidal streams, wind-driven leeway and local shelf effects are not resolved. Positions use WGS-84 latitude/longitude; distances are in nautical miles, speeds in knots, directions in degrees true.