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new shaft & bearings

Discussion in 'Technical Discussion' started by travler, Jun 30, 2012.

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  1. travler, Jun 30, 2012
    #1
    travler

    travler Senior Member

    Joined:
    Oct 14, 2008
    Messages:
    276
    Location:
    roche harbor wa
    we are going in the the ship yard in late august for some major work we are going to replace the shaft bearings from old babbit to new roller bearings , we run cooper in another boat , the shaft is 8 in dia , the shafts and all will be pulled and the tube be replaced any suggestions are comments

    travler
  2. K1W1, Jun 30, 2012
    #2
    K1W1

    K1W1 Senior Member

    Joined:
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    Hi,

    Which bearings are Babbit?

    Changing from a plain white metal bearing to roller bearing is not a 5 minute job in anyone's book.
  3. travler, Jul 7, 2012
    #3
    travler

    travler Senior Member

    Joined:
    Oct 14, 2008
    Messages:
    276
    Location:
    roche harbor wa
    K1W1

    all the bearings are babitt there are five in total , i know this is no small under taking but the boss has a soft spot for the old girl the shaft is a little over 80 ft we are going to do a major re fitt and repower also
    i new 3512 c
    2 new 225 kw gen sets
    1 new hotel gen set 40 kw
    new electronics
    complete sand blast and paint
    clean and repair all fuel tanks as needed
    pull the rudder, repair as needed

    i,am sure the list will grow as i get started (can't hardly wait) i was just looking to see if any one else had been through is process and there thoughts would be , i have used cooper bearings on other boats and we have them in another boat also , as far as electronics go we will use furnnuo, with probably a robertson ap 70 auto pilot any thoughts are other options i should look at

    thanks travler
  4. H4M, Jul 11, 2012
    #4
    H4M

    H4M Guest

    Bearing materials

    You might want to look at some of the new composite materials? one of the latest developments is a material from Maritex in Perth, has had very low wear rates run dry in rudder tests for DNV and is also Lloyds approved. They do oil and water grades as well with some that can be a direct replacement for white metal.
  5. captbpomeroy, Jul 11, 2012
    #5
    captbpomeroy

    captbpomeroy New Member

    Joined:
    Nov 6, 2007
    Messages:
    13
    Location:
    Fort Lauderdale, FL
    Cooper Bearings

    I recently did a full alignment and shaft re-build on a 1968 115' feadship with two cooper bearings on each side of a 30' shaft run. They are great bearings, very simple design and have been in use for a long time in a variety of applications.

    With a full re-power and re-design of your drive shaft arrangement, I recommend you contract a maritime engineer/architect to spec up an arrangement. I cannot stress how important all components from the reduction gears to the prop are to the performance, safety and quietness of the ride. Drive line components and engineering have come a long way since the "old days" and there are a lot of options to take advantage of (vulcan couplings, thrust bearings, dripless shaft seals, hydraulic couplers, composite bearings, etc.). A few things to note on Cooper bearings:

    1. I am not sure of your mounting specifics for the bearings, however, I assume they will be mounted to plumb frames or bulkheads. Note what your shaft run out angle is in relation to the mounting surface. Cooper bearings only allow for 10 degrees of play from center. If you shaft run out is greater than 10 deg in relation to your bearing mounting surfaces, you will need to create an appropriately shimmed surface.

    2. Be sure to re-set the bearings once you are back in the water as the vessel, (which I assume is >50M with 8" shafts) will settle and sit differently in the water. The cooper bearings gaul very easily when there is misalignment. In the same manner, be very adamant that you check tolerances on your cutlass bearings often for irregular wear. Once they begin to wear the load is distributed unevenly on your cooper bearings, causing galling. Once they are galled, they will chatter and "growl"...eventually self destructing.

    3. Install satellite grease points and grease often.

    PM me if you have any specific questions. The coopers are great straightforward bearings. If you haven't already, contract a qualified professional to spec. out the arrangement for yourself.