[travler]

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

[K1W1]

Originally Posted by travler

old babbit to new roller bearings ,

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.

[travler]

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

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.

[captbpomeroy]

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.