What is under the water? Have you ever wanted to take a vacuum cleaner and pull every drop out of a lake or river, or even the ocean, just to see what can be found underneath? With a marine GPS unit, you can do so, in a virtual sense, any time you want. Most of this type of GPS include Sonar capabilities along with your GPS, so that you can see whatever is under your boat.

There are lots of ways this could be beneficial to you. Not only can you use these types of units to find schools of fish when you are out looking for a bite on a warm summer weekend, but you can detect the best routes in and out of your slip without risking bumping a rock along the way. Or, for the more adventurous, there is always the possibility of using a unit such as this for treasure hunting.

The beauty of combining Sonar with marine GPS units is that you can not only locate the treasure, you can come back to find it later because you know exactly where you were. Especially on the open water, it can be extremely difficult to determine your location relative to the land, and there are generally no reliable landmarks to use on the water itself. That is why a GPS can be the answer to your needs.

Some of the features available on marine GPS units include:

1. The ability to adjust the speed of your Sonar ping so that you can locate fish (or whatever you are trying to locate underwater) at varying boat speeds.

2. A numeric representation of the depth of the fish under the water alongside the symbol representing the fish, so that you can see how far down the fish is without needing to take your eyes from the screen.

3. Some units have high definition displays in full color, and use bright lighting to compensate for the glare of the sun.

4. It goes without saying that most of these types of units are water resistant. It is possible to find units that are completely waterproof and ruggedized for use in salt water environments.

5. With your GPS, you can map your favorite fishing spots so that you can return to the exact location where the big one got away and find him again.

If you are new to the world of GPS as a tool for the boater and fisherman, spend a little time learning about what products are out there to meet your needs. There is more to be seen under the water than you ever knew.