Marine GPS’s is one of the best investments you can get when you have a boat, it is a map which can constantly be updated by software downloads. This is extremely important because the sea can change just like that, for example, a storm might disrupt the sea surface below. Your map might say that it is 25ft deep but the storm has now changed it to 15ft, this can be dangerous to a boat, so the GPS calculates the new measurement of the seas surface.
When buying a marine GPS, the first thing you should make sure it is waterproof, this is a very important factor when purchasing one. Since the waves can be very unpredictable at some stages, it isn’t worth taking the risk on breaking the GPS the first time you buy it. Also another important thing you should consider when buying a GPS is the screen, firstly the size, make sure the size of the screen is suitable for your needs. If it is touch screen, make sure it is big enough for your fingers to clearly press against it. Also make sure it works under bright light and at night, sun light can make some GPS tough to read but there are screens out there which don’t get effected by this.
What will you use your GPS for? this is a question which should be asked straight away, if you only need it for mapping out the ocean, then a normal GPS will be fine. If you need it for fishing and finding where the feedings grounds are, then a normal GPS might not be right for you. You might find a GPS you really like, but then find it doesn’t have what you need software wise, but don’t stop there. You might find that there is software available which will make your choice the correct one. So before buying a GPS, do some research and make sure it handles the thing you need.
If your stuck for information and you can’t find a map, I recommend this site: http://www.nauticalcharts.noaa.gov