However, in order for a WIG to fly it needs to have take-off speed same as any plane. A floatplane can not take off in rough waters, a WIG I would guess would be subjected to the same limitations. Maybe the limitations won’t be quite as strict if the WIG is sufficiently huge (and I am talking huge), but that still will shut it down if the wind exceeds a certain limit.

http://www.se-technology.com/wig/index.php has links to pics of the Ekranoplans mentioned.

I agree with a lot of your points tenthije, but here’s some further thoughts.

The large Russian ekranoplans, KM (Caspian Sea Monster), Lun, Spasatel (Civvy Lun planned for ASR work) and the more well known Orlyonok all used boost engines to augment lift and bring the craft into ground effect long before the ‘step’ speed of a flying boat. the KM and Lun used 8 at a noticeable fuel cost. (not good these days)

I don’t know how rough the water would have to be to prevent takeoff, perhaps some of the experts in the “Historical Aviation” forum can equate this with wartime Sunderland and Catalina ops. I have seen photos of Albatross ASR ops in very rough China Sea conditions.

As for your dismissal on speed grounds as opposed to aircraft. The KM cruised at 267mph (430kph) max was 310 mph (500kph) 10 times faster than shipping and weighed in at 544 tonnes. The KM was just an early example and experimental but if this could be updated and enlarged say 4X I think it would interest the fast freight people if costs could be kept lower than the 4 747s it would ‘replace’. No it’s not as fast as a 747 but it’s still fast.

The big disadvantage is the need for water as a uniformly flat surface (not much tundra in the USA or Europe) They could only really be useable on an oceanic port to port network eg New York to Southampton, (Rotterdam would be a problem due to Channel traffic). I see a possible winner as West Coast USA to Japan China and Korea. The cruising height of the KM was 4-14 meters (14-47 ft). I just wonder if this would be adequate for oceanic crossing. I have crossed the Adriatic in a Russian built hydroplane and in rough conditions it rode the inside of the waves and nearly capsized. Nearly everyone was sick and we had to continue the journey on reduced power and on the surface as opposed to planing. A long and arduous trip.

There are so many problems to solve, not the least being excessive engine maintenance due to salt spray ingestion, that I really don’t see a commercial use for them though I’m a great fan of Ekranoplans and would love them to succeed.

Brian