Mar 172017

Here’s a PR film from the US Navy, circa late 1960’s, extolling the virtues of their hydrofoil vessels. Hydrofoils, like jetpacks and flying cars, are old technologies that always seem to scream “future;” but unlike jetpacks an flying cars, hydrofoils have actually entered service. Just never with the US military, with the exception of a handful of the Pegasus class patrol bats (in service from ’77 to ’93). Cool as they were, they just never seemed to quite catch on… they made for some very fast ships, but at considerable expense, and a whole lot of maintenance. And I suspect there was always some paranoia about just what would happen if a hydrofoil ran into a log or a boat or a whale while at top speed.

The film includes some spectacular footage, and some just awful background music.

While hydrofoils had their day fifty years ago, the somewhat similar SWATH (small waterplane-area twin-hull ) concept has popped up much more recently. Witness the “Ghost” from 2014:



 Posted by at 2:06 am
  • Allen Ury

    I love hydrofoils and remain disappointed they didn’t become mainstream.

    • Scottlowther

      Yup. There are a number of technologies that have been proven to work, yet have somehow remained fringe. Hydrofoils, wing-in-ground effect planes, gyroplanes/gyrocopters, airships. They are are *old,* yet kinda scream futuristic.

      • madoc62

        Energy, energy, energy…. And, efficiency, efficiency, efficiency…

        Hydrofoils, as you pointed out, take an enormous amount of energy to get up on to and stay up on to those foils. Yes, they’re much more efficient moving at those speeds on those foils than they would be in the water trying to do the same. But, except for a very small number of applications, such speed isn’t really needed or isn’t worth the expense.

        If you need such speed a helicopter or a plane does it better. SWATH hull layouts get you almost as much as hydrofoils but without the energy requirements.

        WIG machines also take huge energy budgets to get aloft. That’s why the things like the Caspian Sea Monster had so many huge engines bolted on to them. Yes, like hydrofoils, they were far more efficient at those speeds than you’d be able to achieve with a water born hull. And they’re more efficient at hauling lots of weight around relying on the WIG effect than higher flying aircraft which don’t. But they’re very dependent upon the terrain they fly over being pretty uniform and pretty flat. Inland seas and lakes are thus they’re realm and that’s limiting as all get out.

        Gyroplanes were almost helicopters but not quite. Thus, when we finally got actual helicopters they simply couldn’t compete.

    • Egor Petrov

      Yep, that sad. Something like that was river transport and several hundred was produced but than after 80th no more such river ships was produced 🙁

  • publiusr

    Very nice. In space’d be called the sea Eagle.

  • If you want to go faster, get off the water:

  • Rick

    the problem with “fast Stealth boats” is the faster you go, the more wake you generate that increases your visibility. That’s part of why the Sea Shadow wasn’t very fast.

  • Siergen

    A clever technical solution in search of a problem to solve.

  • allen

    I read there was a new captain on one of those pegasus-class ships. they were chugging on the foils along somewhere in the gulf of mexico, and lost their bearings. usual procedure on a normal ship is to order a full stop, which he did. and buried the un-retracted hydrofoils into a shallow bottom. I guess they were stuck there for a few days. not sure how much damage they did.