This is one of those questions that doesn’t have a right or wrong answer. Finding a leak in an inflatable boat can be as simple as taking a sharp look around and getting lucky. Still, some tools make finding leaks easier. Anybody trying to find a leak will want to walk their fingers around all of the seams, looking for areas where they feel moisture. They’ll also want to tap on these areas while listening closely for escaping air. Any air bubbles that come out are good indicators of a puncture or weak spot in your inflatable boat.
Use soapy water. This is an effective way to find it. If your inflatable has small holes, they will be easy to spot with soap and water because soap makes air bubbles. Just wash away all of the dirt that you can see on your boat and then spray it down with soapy water. The air bubbles will make it obvious where cracks or openings in your inflatable boat are. This solution isn’t perfect, though: if you have a big puncture or tear somewhere in your raft, you might not see any evidence of it until much later since a large hole won’t create any bubbles when you use soap and water.
Read more in Inflatable Boats User Manual.