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SWATH ships

Discussion in 'General Yachting Discussion' started by catmando, Aug 21, 2005.

  1. catmando

    catmando Senior Member

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    Just watched a Science Channel program on this multihull design. It featured all kinds of vessels from science research ships and huge charter ships to military vessels. Can someone post a link to a website for it?
  2. AMG

    AMG YF Moderator

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    Abeking & Rasmussen in Bremen, Germany, is building Swath ships. They have some information on their website, unfortunately a Flash-site so you have to find it yourself under the headline Ships and also under Yachts where I found the illustration below; http://www.abeking.com/flash.html

    Look at the movie where they compare Swath to a monohull, unbelievable! Who will be the first to build a big Swath-yacht?

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  3. JonS

    JonS Senior Member

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    Wow, those videos certainly speak for themselves! The first monohull almost disappears under all the water, whilst the SWATH sits ontop the wave and rides it no problem! Surely there is a market for this technology in yachts as well as working vessels?
  4. Codger

    Codger YF Wisdom Dept.

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    Any chance of some photos of the engine room on one of the Swath pilot ships?
    What is the draught?
  5. KCook

    KCook Senior Member

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    The revenge of the humble pontoon! :D
  6. catmando

    catmando Senior Member

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    Thanks for the link Lars. :) The Science channel program also featured vids and the seas were 18-20ft. They showed a glass of water on the SWATH ship and it never spilled a drop!! :eek: :D
  7. catmando

    catmando Senior Member

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    LOL :D :D
  8. Ben

    Ben Senior Member

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    Very interseting, thanks. ;)

    Just one question, in the first video, the naval vessal appears to be much larger, could his apparently poor performance have something to do with his extra length and the distance between waves?

    Perhaps the Swath vessal is aided by the fact that he is small enough to drive up and then down each wave?

    Of course, I could be wrong. :D
  9. catmando

    catmando Senior Member

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    Did you see any pitching motions from the SWATH vessel? I didn't. And it was obvious the SWATH was keeping its speed down to stay with the other ship.
  10. AMG

    AMG YF Moderator

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    Anyway, the difference in pitching was great and it must also influence the fuel economy. As I understand it, the downsides of SWATH is more draught, I have seen figures representing more than 3 m on a 30 m boat, also it is pretty load sensitive which might be controlled with ballast tanks and finally, like all multihulls it will take more space in harbours.

    Besides this, it must be the ultimate hull for comfort at speeds 20-30 knots. I think the first yachts to use it will be explorer types where the stability for handling tenders, submarines and helis is a big advantage.
  11. Ben

    Ben Senior Member

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    I'll try a different angle. :)

    That Swath did look remarkably stable, so they must be onto a good thing.

    I'm a bit of a learner in open ocean things, but those waves seemed to be just the wrong size for the ship. It didn't apear to be handling that swell very well.
    Is that normal?

    The smaller vessel in the second video (not the Swath) was heading into bigger waves and appeared to be staying out of the water better.


    As I said, I'm a learner, so I'm just asking a question. ;)
  12. YachtForums

    YachtForums Publisher/Admin

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    Ben is correct. The length differential of the vessels along with the frequency of swells contributed to the contrast in stability between these two hulls. Had the swells been smaller, with reduced frequency, longitudinal stability would have favored the monohull.
  13. AMG

    AMG YF Moderator

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    I found a site (not very updated but anyway) where they have a lot on SWATH ships, the first patent was awarded a monohull SWATH! (Could be a Swedish invention?)

    They are also trying to develop a tri-hull SWATH which would make sense I think. I like when boats behave like boats and the chances are that this boat will have nice motions at sea?

    http://www.swath.com/Tri-hull1.htm
  14. Ben

    Ben Senior Member

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    Slightly off topic post...

    After watching the SWATH video I was wondering about Princess Marina's beak hull, I was thinking that perhaps the idea is to provide a narower, sharper entry point to improve ride in smaller waves and chop (and economy/speed), but then flair out the hull to give enough boyancy so you don't cut to deep into bigger waves like the naval vessel did.

    Sort of like a half way between ECO's narrow, cutting bow and Octopus's more conventional (looking) roomier bow.
  15. AMG

    AMG YF Moderator

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    If there is any significant effect it is probably to the contrary. The high "chineline" is more of a design gimmick that Espen came up with almost ten years ago on a fast yacht concept which I believe was never produced. Then we have seen it on Skat, where I think it works very well and on Princess Mariana where I think the combination with the sloping nose looks a little strange...

    Here she is in Monaco; http://community.webshots.com/photo/145151065/145151065uOPkbO

    and here is Skat when in Stockholm;

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    Last edited: Sep 9, 2005
  16. Ben

    Ben Senior Member

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    So, now you all know why I don't design yachts. :eek: ;) :)
  17. AMG

    AMG YF Moderator

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    You are right in that the fine entry makes less resistance and also increase the pitching, which the chine should stop. But the higher up it is, the more pitching which is also slowing the boat down.

    With a bulbous bow this problem is much reduced and this is the similarity with SWATH ships. As seen on this drawing the bow wave is built up before hitting the bow (yellow line) and is by then already moving down and to the sides. Without the bulb (blue line) the bow vawe is growing up along the foreship and makes more resistance.

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  18. Ben

    Ben Senior Member

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    Interesting. Thank you Lars. :)

    I love finding out how things work.
  19. YachtForums

    YachtForums Publisher/Admin

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    Came across a commercial ferry with SWATH architecture. Note a deep-v bow section to diffuse waves passing under the hull.

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