(CNN) -- One of the most innovative sailing gadgets of recent times could be sitting in your back pocket.
The iPhone -- and the plethora of apps that come with it -- has become a popular and helpful tool for many sailors.
But with thousands of apps to choose from, it can be hard to decipher the gems from the less-than-helpful.
Some are truly ingenious, developed by engineers and sailing professionals, with the potential to supplant existing technology, while others just don't work.
To make life easier, Mainsail has put together a list of apps, specifically designed for sailors. They are useful, inventive and also quite fun.
Here's what we've come up with. Please add your suggestions in comments at the bottom of the page.
1. iNavX Marine Navigation
Highly rated by users, iNavX is an all-in-one navigational program, providing detailed maps and high-quality charting features including GRIB weather display and waypoint (navigation reference points in space) and track plotting. If you are sailing in the U.S. this app can be very useful, with free access to thousands of detailed marine charts. If you are elsewhere, it is possible to purchase compatible chart software from a number of different sources, Navionics being a popular choice. As with other apps reliant on GPS, battery power is quickly drained if not charged.
A nifty little app displaying tides and currents for locations around the world. Although there are cheaper versions of this app around, the key selling point is its ability to bring up information quickly and easily without internet access -- crucial when you need information in a low-signal area. It's also a handy way to plan the safest, fastest routes well in advance, allowing you to predict tides until 2100.
3. Wind Meter
As the title suggests, this app estimates the speed of wind. Thought up by engineers in Silicon Valley, the app ingeniously measures the volume of wind passing across the microphone and then converts it into speed. There are mixed reviews about its accuracy, some swearing by it, other complaining it won't measure speeds under 12 knots. But, for a thereabouts guide it's quite handy.
Want to improve your race times but don't feel like forking out the big bucks -- this app is for you. Designed as a low-cost alternative to expensive tactical systems, the SailMaster displays boat speed, distance and direction of waypoints, tidal information and has a countdown timer and digital compass. Accuracy depends on a good GPS signal and there have been mixed user reviews, but it's a truly inventive idea. Another drawback of this economical all-in-one is the loss of tracking information when a call is made or received -- so divert your phone.
5. Knots, Splices and Rope Work
This app is essentially a photocopy of A. Hyatt Verrill's 1917 classic treatise on knot tying. It includes scrollable text of descriptions and 154 diagrams of classic knots, splices and rope work. Some complain about its lack of technically wizardry, (there are no animated demonstrations), but the comprehensive list of knots coupled with easy to follow instructions make it a sailor's dream guide.