iRegatta

This is a free evaluation version of iRegatta.

All features are included, but GPS and NMEA0183 input will shut down after 4 minute. All features you would like to use can be bought as In-App-Purchases.
'iRegatta Pro' has Basic, NMEA and AIS features enabled.

iRegatta is a tactical Regatta application as well as a crusing navigation application for the iPhone.

The build-in GPS unit and the unique graphical possibilities of the iPhone, makes it ideal for such an application.

If you have a iPhone anyway, this is a cheap way to introduce you to the benefits of a GPS device, to help you leverage your regatta sailing performance.

A downside is of cause the fact that your iPad is not waterproof! But there are products out there, where you can put your iDevice into, to make it waterproof and still be able to operate it. In this way you can either mount it near your other instruments on your keelboat or strap it to your arm if you are sailing a dinghy.

Features:

Main View.
Here you can see your 4 most important readouts, fore instance Heading, Speed, VMG and Performance.

There also is a lift indicator, showing you if you have been lifted by a wind shift, and graphs showing the development in your speed and VMG over a configurable amount of time and a permormance bar.

Wind direction.
Set your wind direction by storing your heading while sailing on upwind on starboard and port tack, or simply type it in.

Start view.
Here you have your count down (including sync), and you can mark your starting line and iRegatta will calculate the distance to the line and indicate the favorite line end, if wind direction is set.

Statistics view.
View your current position and trip odometer and max speed since last reset. You'll also see a polar diagram with your speed and VMG (wind speed dependent).

Waypoints.
Navigate to your favorite pre-stored waypoints, or create a new temporary waypoint by cross bearing using the iPhone internal camera, or by distance/bearing.

Tracking.
Record your track and view it on the map or export it for further analysis to your computer.

Instead of internal GPS you can get instrument information over WiFi from NMEA0183 instruments. (In-App-Purchase). 

AIS data received over WiFi will be displayed in a Radar-like view. (In-App-Purchase).

iRegatta also comes with a watch app, which will allow you to view data on your watch as well as operate the start line features. Besides that, the watch app will track your sailing as an activity and help you close your activity circles using HealthKit.

Read more detailed information on the apps web page.