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Proper Blocking of Yacht

Discussion in 'Technical Discussion' started by PSW, Apr 24, 2017.

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  1. PSW

    PSW Member

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    So I am getting ready to haul out for bottom touch up and installation of UW lights and addtl Transducer. My previous boat had very specific instructions regarding weight resting on the keel and stands per x number of feet.

    With the new boat there are no figures to go with as reference. Just some well marked sling indicators. So on a 40ft boat is 3 stands per side adequate or is 4 necessary? 25% of the weight resting on the keel or perhaps more up to 35%

    Look forward to hearing the perspective of some of our contributors.
  2. CSkipR

    CSkipR Member

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    On my recent 43 haul out I'm pretty sure there was only 3 on each side. Total weight 48k.
  3. PSW

    PSW Member

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    I am needing to figure out what Cabo likes as my Ocean needed a bed of pillows to not cause damage with the hollow keel. Just trying to figure out what is appropriate for this new rig. Specifically percentage of weight resting on the keel.
  4. Capt J

    Capt J Senior Member

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    A Cabo is built strong.....can put about 3-4 blocks down the keel (or hull bottom) and 3 stands a side is fine....... Generally on most all yachts, all weight is resting on the keel, the stands are to keep them from falling over.
  5. PSW

    PSW Member

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    That will be nice. Any target % on the keel before blocking?
  6. g collis

    g collis Member

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    This older post caught my attention. How do you figure 25%-35% of the weight is on the keel???? ALL the weight is on the keel. The side stands simple keep her from falling over. I'm sure there are rules based on length for how many keel blocks to use + side stands. Recently had my 55' Hatteras convertible hauled. They put 4 blocks under the keel and 7 stands down each side.
  7. Capt J

    Capt J Senior Member

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    This, I concur all of the weight is on the keel.
  8. 30West

    30West Member

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    No, I've seen keels crushed on boats from not enough blocking on the sides, even well-built boats. Contact the manufacturer, there are specific places to block a boat. Do not put all the weight on the keel unless the manufacturer says that is proper.

    There are boats that are designed to take their full weight on their keel, usually smaller boats, or large boats designed for grounding.

    The marks for straps usually indicate solid structural points, balance to even the load on the hoist, and places to avoid lifting on components under the hull like intakes and shafts. They are a compromise.
    Last edited: Jun 9, 2017
  9. Pascal

    Pascal Senior Member

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    When a boat is blocked, it's is first lowered on the keel blocks then the stands are put in place on each side for balance. As the stands are adjusted by hand by turning th threaded adjusters, there is simply no way those short levers can be used to take pressure off the keel.
  10. PacBlue

    PacBlue Senior Member

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    Keel blocks usually go under your bulkheads or transverse frames for proper load bearing.

    The boat stands can bear some weight if you over crank them, but are usually hand tight for stability. 3 per side on a 40 is plenty, plus however many keel blocks that align with bulkheads, probably not more than 3 or 4 in your case. Ultimately, the yard is responsible and the good ones are a bit conservative. Let's see a picture when you have it hauled out.

    Don't forget to have the stands chained from port to stbd, to prevent any accidental "slippage".
  11. 30West

    30West Member

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    The side stands should not be adjusted with the full weight of the boat on them, if it is even possible. Perhaps with enough grease and muscle. Normally the keel is lowered to the cradle or ground, it is blocked to take the weight evenly at structurally strong points, and then lowered to rest on the keel with some of the weight. Then the side stands are adjusted to the hull, then the boat is lowered the rest of the way. On larger boats there is enough flex, that a lot of weight ends up on the side stands as the hull relaxes. How much is usually more of a guess at most boat yards. It would be nice if they put a nautical engineer on the task but they don't.

    If the boat is on straps, the flatter the bottom, the more weight is on the chines. You want to put the side stands at the bow tight, and the side stays at the stern loose, before relaxing the straps.

    I used to haul and block boats as a kid, sometimes 40 to 60+ footers. We still had a lot of big wooden boats then, the big ones flexed a lot.
  12. d_meister

    d_meister Member

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    Generally, if there are professionals in a yard performing a function that could have some liability attached, I keep my mouth shut and leave it up to the yard, their insurance company and God. On one boat that I ran, an 80' custom M/Y, the keel had a tendency to deflect upwards when in the slings or blocked. So much, that the floorboards between the engine stringers crowned in the center. From the point where I discovered that, I had to advise the yards about the best procedures to prevent damage, which included having a diver run the straps between the hull and shafts, adding more jack stands, and minimizing the weight resting on the keel.The boat traveled a LOT, so I had plenty of opportunity to hone my people skills in the way of providing advice:rolleyes:. Generally, it went pretty well, except on an occasion with loading the thing on a float-on, float-off ship. The loadmaster very icily told me they knew what they were doing . He was really P.O'd when he had to flood the ship back down to improve the blocking.
  13. PSW

    PSW Member

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    My first experience with blocking a boat was my previous vessel a 1998 Ocean Yacht. In the owners manual it very clearly states to not put more than 25% of the load on the keel as it is hollow. The boat wanted 4 stands per side as well and this was on a 4oft Sportfish. I knew this was not the norm but it was what I was used to. Fast forward to the current boat and I looked in the manual and there are no parameters set. Prior to launch I call Pipewelders in FL knowing they commissioned a number of Cabo's and having recently had my boat there before loading for transport. They indicated that they place 30% on the keel and then tighten up the stands before relaxing the straps. Perhaps I heard him incorrectly. I figured what you are all indicating in the last few posts. Place 50% to 75% on the keel and stern with the remaining load on the 3 stands per side to balance the boat. It seems there are a number of opinions on this and I am not desiring to tell my yard what to do and they are great to work with but I do understand that all boat are different and I would very much like to know for future reference how exactly Cabo's are best blocked.
    As of this time I feel that 3 points on the keel and 1 addtl point at the stern on centerline with 50% load released from the travel lift and then the remaining load distributed once 3 stands per side are in place and snug.

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