If you turn the key on your boat and nothing happens, there are a few possible explanations. The most common reason is that the battery is not working. If the battery is dead, you will need to replace it. Another possibility is that a fuse has blown. Check all of the fuses on the boat and see if any of them are burned out. If so, replace them with new ones. Finally, it's possible that there is an issue with the starter motor itself. This is a more serious problem and will require a mechanic to fix it.