does the chamber have a hole? or is the lid of the chamber not closed properly? otherwise inflate it again and leave it inflated overnight. then immediately hose down the inside with fresh water.... it must be clean and, if possible, free of sand. did you put the boat into the sea for the first time? or a second time? was it folded up? when storing it, it is better to leave it inflated a little so that no edges develop. this is where cracks often occur... so: inflate. pay attention to the indicated pressure capacity. were there too many people in it? you must not exceed the payload. if all this is not helpful, return it and ask for a replacement, otherwise this is a safety factor... and otherwise... have fun with it... my 3 is still in the tinkering room, because i took the 4... only the engine doesn't run yet... 4ps etc... but concerning stability and air in the chambers the 4 is top... even withstands days of sunshine. like the 3.... watch out for dic inside caten between floor and 2 chamber... no dirt and salt!!.. so have fun and don't go too far out if you are too unsure... and have glue parts ready for patch repair... sincerely.... radu k