Boaters have special requirements for a bicycle. It needs to fit into small spaces, hence it needs to be a folding bike. They also have a hard time with standard derailleur drivetrains, because the narrow chains rust. This hinders shifting and the overall rideability of the bicycle. Additionally the derailleur creates a risk, in unstable water the bike will be thrown around and the rear derailleur can act a lever bending the hanger. Boaters prefer internal hubs on folding bikes because they can use stainless belt drives or steel chains to mitigate the risks of rust. Additionally, they don't use a rear derailleur which removes the risk of bending the derailleur hanger. Boaters love our miniB, or 8H/11H with belt drives. Below are pictures of an older Downtube folding bike on a sailboat.