iSailGPS : NOAA USA RNC Charts 4+

Marine Nautical Chart Plotter

James Associates Inc.

    • $7.99



Unleash the navigation potential of your iPhone or iPad with SailGPS! Turn your device into a high-performance GPS receiver with USA NOAA Raster Nautical Charts, even without a cell signal!

Rated “Best Choice — Excellent” by

Caught in a storm on the water and your chart plotter fails? Don't worry! Download this app now and regain full navigation capabilities to safely return to port. Better yet, buy iSailGPS today ensuring you're prepared for any situation, even in areas with no cell service.

iSailGPS eliminates sign-ups, ads, subscriptions and in-app purchases, making it more affordable, hassle-free & respectful of your privacy.

Unrivaled Features to Enhance Your Journey:


Record tracks as you sail, even in the background. View them on the chart and in a Speed & Course Over Ground graph.

Mark waypoints precisely using topo or satellite maps, place names or addresses, geotagged photos, or by projecting from a known point.

Set a quick GoTo waypoint or a full route and see the course (COG), heading (HDG), bearing (BRG), direction, distance, cross track error (XTE), Velocity Made Good (VMG) and Estimated Time of Arrival (ETA) at your destination and intermediate points. Perfect for racing enthusiasts.

In a Man Overboard (MOB) emergency a single button press marks your current position & starts navigating to it.

Create customized routes using waypoints, recorded tracks, or imported GPX, KML or TCX files. Advanced route editing.

Send GPX and KML waypoint, route, track and map list files via AirDrop, eMail, Messages, or iCloud Drive.

View the sun & moon position, rise times & set times for any date & place on earth.

Send data to other apps such as Google Earth.


Access to all NOAA RNC Charts for USA waters with no extra charge. Download using WiFi or cell service.

Our chart files are optimized to download faster & use less storage memory. Store up to 2200 charts to use anytime at sea without cell service.

Stitches charts & automatically switches between downloaded charts as you sail. Choose detailed or overview charts.

Print & Share chart images overlaid with waypoints, routes & tracks.

Measure distance & direction between any 2 points.

NOAA charts don't include most inland rivers & small lakes. Use our iHikeGPS app for these.


Tap Help in the app.
Online Manual:
Email developer:


The National Oceanic & Atmospheric Administration provides both RNC (raster) & ENC (vector) charts.

The great advantage of the high resolution RNC charts used by iSailGPS is the high level of detail produced by professional cartographers that is unobtainable on any vector-based chart. ENC Vector Charts only show a coastline, water depth, navigation aids & minimal details.

These RNC Charts differ from vector charts in that each chart covers a specific area, just as paper nautical charts do. Switches automatically to a new chart when your boat leaves the area covered by the previous chart. For most locations, there are multiple charts at different scales with different levels of detail & areas of coverage.

Paper charts can have multiple panels, each showing a different area or scale. Each digital panel is individually displayed by iSailGPS with a north-up orientation.

Other more expensive marine software uses these same RNC charts. iSail GPS is priced to make it readily available to all boating enthusiasts.


Use iSailGPS on any iOS device even if you don't have a cellular data plan for it. iPhones & WiFi+cellular iPads support full navigation. For WiFi-only iPads & iPod touch, an iOS-compatible external GPS receiver is required to show your location on the water & record tracks. However, you can view charts using the iOS device alone.

Winner of the Practical Sailor Editors’ Choice Award.

Discover a safer and more enjoyable sailing experience with iSailGPS!

What’s New

Version 9.4.4

I'm continually improving this app so it will be even more useful! This version is updated for iOS 17.3.

What's new in iSailGPS when compared with other available NOAA chart apps?

• You don't just see waypoints and routes displayed on the chart, you can actually do real great circle navigation to those waypoints and along those routes. You get information such as Estimated Time of Arrival, current bearing and heading, and remaining distance to your intermediate and final destinations.

• You don't just see individual charts. Whenever the map projection is compatible (which it is most cases), you can see adjacent charts with their margins removed stitched together seamlessly, even when the chart scales are different. For example you can see the approach chart and the corresponding harbor detail chart both together on the same screen.

• You can create, import, edit, export, and navigate both on routes based on a recorded or imported path, and on routes based on a series of waypoints.

• iSailGPS's code size is kept very small by efficient programming so in an emergency, you can download it easily even over a weak cell connection.

• The current version of iSailGPS runs on the latest devices and also on older devices with older versions of iOS , all the way back to devices such as the iPhone 6.

• There is never any confusion over what charts you have available offline. They are clearly listed by NOAA chart name and number, and shown on an overview map.

• Check the App Privacy section. We don't know who you are when you are using iSailGPS. We never send your current location or your recorded track to our servers. Hence we cannot and don't use your location data. We cannot and don't provide your location data to anyone else. Unlike other mapping apps that profit from using your location data in ways that do not keep it private, iSailGPS maintains the highest level of data confidentially.

Ratings and Reviews

3.9 out of 5
63 Ratings

63 Ratings

SpudV ,

Always Impressed

After investing a little time to understand this app, I found it to be extremely valuable and accurate. I was won over, when we used it to navigate across the Chesapeake Bay at night. The waypoint marker we were heading to was supposed to be a flashing light but the light was out and we were a little uncertain that we were on course. When we suspected we should be at our destination marker we turned on our spot light and found ourselves perched with the marker on our port quarter. Can’t believe this app is only $7.99.

buzz4rd ,

Excellent App

I’ve been using this app for about a year and I’m extremely happy with it. I can set waypoints and routes right on the app just like I would on a chart. Then follow the route, and even reverse it on my iPad or iPhone. I can send a route from my iPad to my iPhone and it brings the waypoints with it. You can take a screenshot of the route and print it out, so you can check off each waypoint as you pass it. They even added the latitude and longitude of each waypoint to the route screen. They’re very responsive and I highly recommend this app.

Howkola1 ,

Great app!

I love this app! It gives me exactly the info I need when racing or just sailing. I’ve set waypoints for all the government and private buoys we use to set our race course. Then all I have to do is create a route by choosing the waypoints to be used for that day’s race. Then I have SOG and bearing and VMG to each mark and more. Amazing! The learning curve is a bit steep, but well worth it. And if I have questions, the developer is super-quick to respond. Highly recommended.

App Privacy

The developer, James Associates Inc., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Linked to You

The following data may be collected but it is not linked to your identity:

  • Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    Up to six family members can use this app with Family Sharing enabled.

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