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Marlow 65' seatrial vibration

Discussion in 'Marlow Yacht' started by bayoubud, Mar 8, 2017.

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  1. bayoubud, Jun 27, 2017
    #81
    bayoubud

    bayoubud Senior Member

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    That design would probably work on a planning hull too.
  2. JWY, Jun 28, 2017
    #82
    JWY

    JWY Senior Member

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    The 1994 custom built trawler in the picture is 52 feet (58LOA), twin Lehman 135hp. Draft is 5', displ 90,000lbs. . The photo is from LMC. The owner built it for himself but never cruised.

    Judy
  3. bayoubud, Jul 12, 2017
    #83
    bayoubud

    bayoubud Senior Member

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    Judy, he built himself a fine cruiser. Too bad he did not get to cruise it as planned. If it was larger we would be taking a tour.
  4. Capt Ralph, Nov 15, 2017
    #84
    Capt Ralph

    Capt Ralph Senior Member

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    Been slightly involved with a '04, 71' Explorer.
    No vibrations. Smooth and fast.
    She does have the exhaust deflectors.
  5. bayoubud, Nov 16, 2017
    #85
    bayoubud

    bayoubud Senior Member

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    rc, exhaust mods might be the reason for the smooth ride. As mentioned earlier there is a lot going on with their design.
  6. Cowger, Jun 25, 2020
    #86
    Cowger

    Cowger Member

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    Digging up a very old thread, sorry, but this was a fascinating read. What got me here is I am looking (online) at a Marlow 70' and am wondering if I should even bother to consider her at this point.

    Here are a couple pictures. The props seem small and rather closely spaced, but don't seem to have the problematic tunnels mentioned in this thread. Not sure where the exhaust ports are (that lead to the cavitation / vibration mentioned above). The two ports on either side of the transom at waterline seem too small to be the main exhausts.

    Thoughts?

    1.jpg 2.jpg
  7. Capt J, Jun 25, 2020
    #87
    Capt J

    Capt J Senior Member

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    I would say those are problematic tunnels. You have whatever those giant things (shaft tunnels) are that the shafts are encased in, making the water veer away from the props and the props trying to suck the water that is flowing around them versus just a shaft and normal small strut. The thing sticking down in the first photo, is the tail end of exhaust deflectors, which in my opinion are a bandaid for poor placement of the exhaust.......
  8. Cowger, Jun 25, 2020
    #88
    Cowger

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    Yes, now I see the tunnels very clearly. Thanks. Moving on...

    Bryan
  9. bayoubud, Jun 25, 2020
    #89
    bayoubud

    bayoubud Senior Member

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    One thing to consider, not many boatyards out there that are familiar with their design and knowledgeable to repair drive train issues. Those exhaust deflectors were added after the boat was built, must have had some exhaust related vibration issues related specifically to their design.
  10. olderboater, Jun 25, 2020
    #90
    olderboater

    olderboater Senior Member

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    And ultimately the only way to find out if they were effective is through an intense and thorough sea trial and that likely requires an offer and money.
  11. rtrafford, Jun 25, 2020
    #91
    rtrafford

    rtrafford Senior Member

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    Wow, first time seeing this build out of the water. The prop placement reads of a cyclops. Even with the tunnels, how can those props not impact each other with wash?
  12. bayoubud, Jun 25, 2020
    #92
    bayoubud

    bayoubud Senior Member

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    No kidding, stabilizer fins, underwater exhaust, tunnels, shafts running thru velocijet struts keels, rudders, and trim tabs. If the stabilizers or trim tabs are not operating properly you will get exhaust in a tunnel with vibration limiting speed. Parallel alignment of shafts and velocitjet strut keels could cause an issue too. Complicated design.
  13. Capt J, Jun 25, 2020
    #93
    Capt J

    Capt J Senior Member

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    One of the scariest yachts I ever ran, one of the top two, was a new 2014 56' Marlow. 2-4' seas off of the starboard stern quarter, at 16 knots, boat rolled so hard and fast one time that a Personal cooler flew across the entire flybridge and hit the side of the flybridge on the opposite side without ever touching the ground, it almost ejected all of us.

    With all of that junk in the water, it appears that David Marlow took ideas from every yacht ever built and just threw them altogether on one yacht. LOL
  14. olderboater, Jun 25, 2020
    #94
    olderboater

    olderboater Senior Member

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    David Marlow is a mad scientist. He can't stop. He is always looking for a little more or better, so no two boats come out the same. That means some are delivered with permanent issues that can't be corrected. He's knowledgeable and has a lot of ideas, but the execution is missing as he just decides he could do this or that and be a little faster.
  15. Capt Ralph, Jun 25, 2020
    #95
    Capt Ralph

    Capt Ralph Senior Member

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    I can't mention the boats name but it was a tall Marlow the owners loved. In the engine room, I could play half court between the in line Cats.
    I have been studying that last bottom picture (post 86). These engines are way closer than the Marlow I was working on.
    Was he looking for more dense water or a different ER layout when he brought the engines closer?
    I can imagine NO room between the blocks per these pictures.
  16. Capt J, Jun 25, 2020
    #96
    Capt J

    Capt J Senior Member

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    Perhaps he was looking at pictures of Fountain raceboats and decided to stagger the motors for better weight distribution. LOLOLOLOL

    Odd thing is the Marlow's are slow boats, he's always looking for a little more speed???? Can't figure that one out.
  17. rtrafford, Jun 26, 2020
    #97
    rtrafford

    rtrafford Senior Member

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    I've always enjoyed looking over Marlows at the dock. This Marlow on the lift, however, that's a cacophony of nonsense underwater. Those props so close together, neither with even the slightest opportunity to grab clean water...
  18. bayoubud, Jun 26, 2020
    #98
    bayoubud

    bayoubud Senior Member

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    The one we sea trialed had a decent ER. The crew quarters in what is normally the lazarette was a different story. It was crowded and limited access to hull and equipment. The "Throne " as they called it (the head) sat over the Rudders and trim tab systems had very limited access. This was a early 2002 model, no telling what changes they made later. Seems to always be a lot of them on the market.
  19. Cowger, Jun 26, 2020
    #99
    Cowger

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    Engine room of this particular boat. Cat 3406Es. Doesn't seem to be too bad, but I'm still not clear why the props are so close for a boat with an 18'4" beam.

    3.jpg
  20. Pascal, Jun 26, 2020
    #100
    Pascal

    Pascal Senior Member

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    I guess you Really need a stern thruster with the props being so close!

    Lazzara used enclosed shaft housings on the C30s powered 84. They are supposed to reduce drag but Probably not by much since they didn’t use it in the C32s with larger shafts.

    The 84 also has similar fences to prevent the exhaust from being sucked in by the props but it s also one of the few planning boats I ve seen without trim tabs.
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