Tack Pad

Tack Pack is a free iPad passage planning tool for sailors. It computes tacking solutions for up or down wind destinations under selected wind and current conditions. Tack Pad uses Polars to estimate speed and leeway and will provide estimated time of arrival as well as detailed information about the tacks, courses to steer, speed, course over ground and other navigation information.

Tack Pad is not a GPS navigation app, nor a chart plotter. Tack pad is meant be to used in passage planning alongside a chart plotter or with paper charts, and provides solutions most chart plotters don’t address. Namely that sailboats can’t always follow a straight line from one gps point to another. Even where a straight line course is possible, it’s not always the fastest.

The problem

  • Traditional chart plotters don’t account for sail tacking, they only provide a straight course to steer which is not always possible to follow while under sail.
  • A failure to account for tacking means that chart plotter ETAs are inaccurate.
  • If chart plotter software does provide for tacking, they’re hard to interact and don’t allow you to easily explore different weather scenarios.
  • Chart plotters don’t account for current and leeway during planning. Though GPS plotters do compensate for these factors while underway, this information is not available to you when planing a route. This means you really don’t know what your track will be, and which obstacles or obstructions will be in your way.
  • Chart plotters don’t use polars for planing the fastest course to steer.
  • Some plotters can provide routing solutions using grib files, but usually only provide a single solution to predicted weather. This doesn’t allow you to explore what-if scenarios in case the weather doesn’t behave. Nor allow you to explore alternate courses in order to hedge against unpredicted weather changes.
  • Of course there are some chart plotters (mostly PC based) which do address these issues, and more…. but they’re expensive, complicated to use, and also require a PC on board.

Tack Pad addresses these issues, but is not a GPS navigation application. This is a passage planning tool to use with your other navigation tools, whether they be chart plotter or dividers. If you don’t navigate or really understand why you’d want this tool, then it’s not for you. In this case maybe a standard chart plotter for the iPad is what you are looking for and we can recommend the following:


Like Tack Pad this application correctly solves tacking problems and computes accurate ETAs, but it’s focus is on plotting while underway as opposed to exploring options during pre-planning.


This is a complete chart plotter solution that provides for route planning and navigation while underway. Good support for free and commercial charts from multiple venders through X-traverse. No support for sailing.


This application is easy to use and excellent for route planning, but it’s not geared towards sailors and doesn’t deal with tacking. Navionics is a chart provider. You get their chart and no option to load others.

Tack Pad uses algorithms licensed from SailTimer Inc., the makers of the SailTimer app mentioned above. These algorithms are used to compute tacking angles and tacking ETA.

Tack Pad - Rudder Nut LLC