Wave cancellation design; Blue Magic

Discussion in 'Boat Design' started by David Kraaij_Lutt, Mar 5, 2018.

  1. David Kraaij_Lutt
    Joined: Mar 2018
    Posts: 1
    Likes: 0, Points: 1
    Location: hillegom

    David Kraaij_Lutt New Member

    I recently saw this boat for sale;
    BLUE MAGIC - Alu One-off Motor Boat for sale in Netherlands | Boatshop24 https://www.boatshop24.com/en/blue-magic-alu-one-off/Motorboat/1126800
    You might notice its interesting underwater shape. It was designed by engineer Bernard Gellekink who also had a patent on the design (since expired);
    https://patentscope.wipo.int/search...o.int/search/en/detail.jsf?docId=WO1995009102
    The idea is that most of the volume is situated in the thick keel which should act as a slender body, while the broader sides are only slightly immersed for stability. Furthermore there should be some wave cancellation between the wavetrains generated by the keel and rest of the body. This should make for efficient running at speeds of about 15 knots.

    I wish I knew whether it really works... That the boat is for sale after sitting unused for years is not the best of signs, on the other hand it took the designer apparently 10 years to outfit and launch the boat after the casco was completed, so maybe he just lost interest.

    blue magic.jpg
     
  2. Ad Hoc
    Joined: Oct 2008
    Posts: 6,609
    Likes: 617, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    well, here is your answer :)

     
  3. SamSam
    Joined: Feb 2005
    Posts: 3,900
    Likes: 196, Points: 63, Legacy Rep: 971
    Location: Coastal Georgia

    SamSam Senior Member

    How does that explain whether or not the design works?
     
  4. Ad Hoc
    Joined: Oct 2008
    Posts: 6,609
    Likes: 617, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    So..you think you've invented the best thing since sliced bread. You patent it, convinced it works and everyone will want it.

    1) It is amazing everyone wants one, huge success...it works!
    or
    2) Doesn't do what is claimed....sells nowt.

    Thus which one is worth explains whether a patent has expired or not....!
     
  5. SamSam
    Joined: Feb 2005
    Posts: 3,900
    Likes: 196, Points: 63, Legacy Rep: 971
    Location: Coastal Georgia

    SamSam Senior Member

    The patent link doesn't work so there's no telling when it started. Although there are (at least in the USA) a number of periodical renewal fees to keep a patent in force, all patents expire eventually in 20 or 22 years. You are right though, if you've never heard of the product, it probably didn't work as well as planned. And if the patent expired early, that is a signal that maybe it didn't work so well.

    It looks like it would slap and pound the water and not manuever too easily. The thruster would help when going slow, but to turn a circle at speed looks to need plenty of room and no stray currents.

    I'm wondering if this scheme does generate wave cancellation at a certain speed, will it at other speeds amplify wave generation?

    They show no photos of the engine, being stuck down in the keel it's probably not a pretty picture.

    The price looks to be low, especially compared to the water wall pusher at the bottom of the advertisement page. There's a boat that needs some wave cancellation magic.
     
  6. SamSam
    Joined: Feb 2005
    Posts: 3,900
    Likes: 196, Points: 63, Legacy Rep: 971
    Location: Coastal Georgia

    SamSam Senior Member

    Plus, aren't the authorities in Europa fixin' to heavily regulate or even eliminate diesel engines?
     
  7. Mani Kandasa
    Joined: Mar 2016
    Posts: 28
    Likes: 0, Points: 11, Legacy Rep: 10
    Location: Iowa

    Mani Kandasa Junior Member

    The idea is to use the diverging bow wave from the center-hull/keel to generate extra lift on the side planing hulls? Might work better if the center-hull had a bit more displacement up front and not as deep, and gradually going to zero depth at the stern. Kinda like a Wigley hull squished flush at the aft.
     
  8. Rurudyne
    Joined: Mar 2014
    Posts: 1,163
    Likes: 36, Points: 48, Legacy Rep: 155
    Location: North Texas

    Rurudyne Senior Member

    Or ...

    3) it looks weird so no one wants it.

    4) something else went wrong ... like bad slamming as has already been suggested.

    The hull looks kinda like the forward 2/3rds of Bolger's 40' diesel design; however, the the deadrise angle of the wider bits seems more shallow. IIRC reading about the Bolger, this thing is to be faster and maybe it was meant to get a bit up on plane.

    Another possibility is that even with the wider part it is still very narrow up front which limits internal volume. Have you seen a top down picture? I'm betting it has a near arrowhead appearance just because that would help eliminate the possiblility of slamming.
     

  9. Joao Pedro Silva
    Joined: Mar 2018
    Posts: 3
    Likes: 1, Points: 3
    Location: Rio de Janeiro - Brazil

    Joao Pedro Silva New Member

    I tend to be very skeptical about this design. With most of the buoyancy generated by the aft part of the boat, wich is wider, I dont't know if the "slender body" characteristics would be achieved. And even if they were, if that would be sufficient to counteract the downsides of this design. Besides the poor maneuverability, the gain of wave-making resistance and friction resistance would overcome the gains desired in wavetrains cancellation and slender body characteristics IMO. I'd like to see some articles about that design though.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.