Click for Glendinning Click for YF Listing Service Click for Westport Click for Nordhavn Click for Perko

SWATH ships

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

You need to be registered and signed in to view this content.
  1. catmando

    catmando Senior Member

    Joined:
    Mar 3, 2005
    Messages:
    471
    Location:
    Arlington Tx
    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

    Joined:
    Jul 26, 2004
    Messages:
    5,375
    Location:
    Sweden
    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?

    Attached Files:

  3. JonS

    JonS Senior Member

    Joined:
    Feb 7, 2005
    Messages:
    362
    Location:
    -
    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.

    Joined:
    May 29, 2005
    Messages:
    923
    Location:
    Western Canada
    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

    Joined:
    Jun 24, 2005
    Messages:
    1,160
    Location:
    Phoenix
    The revenge of the humble pontoon! :D
  6. catmando

    catmando Senior Member

    Joined:
    Mar 3, 2005
    Messages:
    471
    Location:
    Arlington Tx
    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

    Joined:
    Mar 3, 2005
    Messages:
    471
    Location:
    Arlington Tx
    LOL :D :D
  8. Ben

    Ben Senior Member

    Joined:
    Feb 9, 2005
    Messages:
    176
    Location:
    Melbourne Australia
    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

    Joined:
    Mar 3, 2005
    Messages:
    471
    Location:
    Arlington Tx
    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

    Joined:
    Jul 26, 2004
    Messages:
    5,375
    Location:
    Sweden
    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

    Joined:
    Feb 9, 2005
    Messages:
    176
    Location:
    Melbourne Australia
    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 Administrator

    Joined:
    Dec 22, 2002
    Messages:
    20,353
    Location:
    South Florida
    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

    Joined:
    Jul 26, 2004
    Messages:
    5,375
    Location:
    Sweden
    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

    Joined:
    Feb 9, 2005
    Messages:
    176
    Location:
    Melbourne Australia
    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

    Joined:
    Jul 26, 2004
    Messages:
    5,375
    Location:
    Sweden
    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;

    Attached Files:

    Last edited: Sep 9, 2005
  16. Ben

    Ben Senior Member

    Joined:
    Feb 9, 2005
    Messages:
    176
    Location:
    Melbourne Australia
    So, now you all know why I don't design yachts. :eek: ;) :)
  17. AMG

    AMG YF Moderator

    Joined:
    Jul 26, 2004
    Messages:
    5,375
    Location:
    Sweden
    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.

    Attached Files:

    • Bulb.jpg
      Bulb.jpg
      File size:
      48.9 KB
      Views:
      6,363
  18. Ben

    Ben Senior Member

    Joined:
    Feb 9, 2005
    Messages:
    176
    Location:
    Melbourne Australia
    Interesting. Thank you Lars. :)

    I love finding out how things work.
  19. YachtForums

    YachtForums Administrator

    Joined:
    Dec 22, 2002
    Messages:
    20,353
    Location:
    South Florida
    Came across a commercial ferry with SWATH architecture. Note a deep-v bow section to diffuse waves passing under the hull.

    Attached Files: