In the grand scheme of things, there isn’t a great difference between the three. A dinghy is a small recreational boat that can be used for racing or saving lives on a sinking ship (e.g. the Titanic). Most dinghy boats are used as lifeboats and carried aboard another larger boat. Inflatable dinghies are the most popular because of their light weight and storage capabilities. A pontoon boat is similar to a catamaran. The only thing is that when we think of a catamaran, we think back to the cruise we took to Mexico and that optional tour to the beautiful Marietas Islands. Anyways, a catamaran isn’t always a grand escape. Pretty much, a catamaran is a walkable surface on top of an inflatable bottom. So, to make it simple, any boat can be an inflatable boat if it puts it’s mind to it.