This is about sailing around on a boat, and then wanting to stay in a harbor for the night without having made reservations earlier. So people are free to just sail around and can find a place to dock for the night without worries.
This prevents having to sail around from one harbor to the other to find they are full and wasting fuel and time looking.
Additionally, this app allows finding a harbor in the area with the amenities desired. (Restaurant, playground, entertainment.)
Initially, this was starting in the Netherlands, and I found 2 apps already existing, and that there are printed guide books for the same, but not sure if I found books covering the Netherlands. The 2 existing apps were barely started, lacking severely, and seemed to be possibly abandoned.
Then a friend found a third app, and it seemed to be progressing, although still just beginning. At this point, I dropped this idea, as it would be very intensive to try and compete.
Later I realized, the reason the 2 apps seemed to be stalled at that point, and why the 3rd app wasn't a skyrocketing business, is there is just too little of a market. Most boat people in the Netherlands just stay in / go to one harbor, or regularly the same ones. Ones traveling around usually plan and reserve ahead of time.
There is a market, just small, and it may be difficult to reach the target audience effectively.
And as I typically do, I had planned and worked this app out, with many features, some of which would have probably remained unique for sometime before being imitated. Rapid expansion Europe wide, and eventually world wide, were also planned, before I decided to drop this.