I'm currently developing an iPad app to aid navigation under sail. The app is used to calculate tacking solutions for destinations upwind under various wind and current conditions. To set expectations... the app is not a gps navigation app or chart plotter, it assumes some knowledge of basic navigation techniques, and is not geared towards the novice sailor. It supports multiple waypoints, each with it's own wind and current conditions, uses polars with estimated leeway, calculates total ETA, time on tacks, x-track error for tack points, etc. Waypoints are entered as distance and bearing and this being an ipad app, everything is easy to drag around in order to rapidly try out various wind and current scenarios. Solutions are computed as you drag items around. This is a tool to use along with a navigation app or paper charts.
The app is essentially done, but I 'd need some feedback and basic sanity check before I release it :) To run the app you'll need an iPad running ios 5.0 or later and have acces to a mac or pc with iTunes. You'll also have to email me your iPad device ID, as I'll have to digitally sign the app with the ID in order for it to run on your iPad. Apple makes that part a little complicated. If you're interested in being a beta tester and giving me some feedback, then please email me: tim at ruddernut dot com.