[CliffordK (OP)]

It has been a few years since I've been to England.  At that time, the train stopped in France, and started again in Dover, and there was a big gap between the two.

Anyway, I was thinking about shipping.  Then about ground-effect craft.  Then the hovercrafts. 

I started wondering why not build a hovercraft so that it would be more or less sealed on the sides with a rigid hull, with a flexible hull on the front and back.  Somewhat like a cross between a catamaran and a hovercraft.

You may or may not be able to drive it up onto a parking lot, but it would seem like you could gain efficiency in travel by eliminating the loss of air out the sides of the craft, and might not have a major loss of performance.  The craft could still distribute weight on the cushion provided by the air.  If designed right, it should be able to use air escaping out the back for thrust.  Presumably it could be made with very low draft, or optimally could be dynamically configured for zero draft.

[Geezer]

It must have been a while. The trains don't need to stop these days.

The primary advantage (or maybe the only advantage) of a hovercraft is that it can operate on water or land. I suspect a large amount of fuel is consumed just keeping the thing supported on air. If you want to build a water only craft that has a lot less drag, a hydrofoil might be a better option.

[namaan]

I'm not sure but it may simply be that the reality of driving the craft on land require something that won't break if its sides/bottom hits a hard surface. In fact I saw a small feature on it and how the inflatable panels on the largest hovercraft are removable in case one of them are ruptured.

[CliffordK (OP)]

I thought one of the reasons that the hovercraft was used in England was due to the speed and capacity as a ferry.  The ability to drive up onto a parking lot would have been a bonus, but then it would have required special ports to be built.  Are they able to dock over water?. 

The military may use them as landing craft due to the ability to land on beaches, but I'm thinking of more civilian applications.

Anyway, I was thinking that one might be able to reduce drag by essentially floating a large ship on a bubble. 

In a sense, a hydrofoil is similar by reducing hull area exposed to the water, or perhaps one could combine the concepts.