Old SeamanOld Seaman
DEMO DATA · NOT FOR NAVIGATION
DEMO · NOT FOR NAVIGATIONOnline
Simulated vesselPatapsco approach
--kt wind --gust --ft waves --ft depth
NowFri 9 AM

Forecast

<12 kt12-1717-2222-2828+Arrows point downwind; wind is named by where it comes from. The thin bar under the hours is a DEMO GO, DEMO CAUTION or DEMO NO-GO calculation at this spot. Amber numbers are near your limits, red are over. The water-level curve includes the synthetic wind-driven change.

Route

Departure windows

Wind alerts

Alert me at this spot when wind reaches 18 kt

Boat profile

About this prototype

Old Seaman puts weather, chart and tide on one time axis. The shading is charted depth plus the tide and wind-driven water level for the hour you pick, compared with your boat's draft and margin. Routes are checked leg by leg at the time you will actually be there. DEMO GO means within the limits you set in Boat for this synthetic scenario only; it is not a navigational recommendation.

Coastline © OpenStreetMap contributors (ODbL). Model names label synthetic scenarios; no ECMWF, GFS or HRRR data is used. Bathymetry, tide, stations and every GO or NO-GO are demo values. Not for navigation.

Location and compass are optional, permission-gated device sensors. Readings remain in memory only, stop when the app is hidden, and are never saved by Old Seaman. Compass shows the screen direction relative to magnetic north (°M); hold the device flat and away from metal. The map arrow shows GPS course over ground, relative to true north, only while moving. Your phone direction is not the boat's heading.

Loading chart...
OLD SEAMAN

Chesapeake briefing

PLANNING INFORMATION ONLY · NOT FOR NAVIGATION. Live sources do not validate demo routes or under-keel clearance.

Official sources load when you open this briefing.

GPS is optional. Your device position is not sent to data providers.

NOAA chart reference

Charted depths & hazards

NOAA Chart Display portrayal, not a certified navigation chart. Depth units and datum are defined by the chart, not this app. No vessel marker, depth interpolation, route or clearance calculation is placed on this image.

On demand to conserve cellular data. Chart revision not verified.

Download official NOAA ENCs · Open NOAA chart viewer

Before getting underway

  • Verify current official charts, notices, depth sounder and an independent compass.
  • Check the latest marine forecast and warnings for your entire passage, not just this point.
  • Download your navigation charts before losing cellular coverage. This app caches its shell and a short-lived briefing, not offline navigation charts.
  • Check battery, communications and safety equipment. Keep a proper lookout.

Observation stations and forecast grid points are not your boat. Tide predictions exclude unpredicted water-level changes. Current measurements apply to the named station and instrument bin, not the entire bay. Missing data is never treated as calm water or zero depth.