Cutlass Bearing Replacements


Click for larger image

The final major project we completed at Saxon Wharf in Southampton was replacing the cutlass bearings on the rudder shaft and the wing and main propeller shafts. On inspection after removing the cutlass bearing, our main propeller shaft was badly corroded with some of the pits running quite deep, so we opted to replace it during the job as well.

Below are are highlights from January 9th through 24th, 2018 at Saxon Wharf, Southampton, UK. Click any image for a larger view, or click the position to view the location on a map. And a live map of our current route and most recent log entries always is available at mvdirona.com/maps

1/9/2018
Click for larger image
Rudder Post

James using our largest torque wrench to loosen off the rudder arm bolt in preparation for rudder bearing inspection and replacing the rudder packing.
Click for larger image
Wing Prop Removed

The Gori wing propeller disassembled.
Click for larger image
Removing Main Prop

Roland Mcildowie and Jack Woodford of Proteum removing our main propeller in preparation for changing the cutlass bearing.
Click for larger image
Main Prop

Our main propeller hasn’t been off the boat since we took delivery. It’s a hefty beast.
Click for larger image
Main Prop Shaft

The main propeller shaft with the propeller removed. The plate just above is where the Spurs shaft-mounted cutter system mounts. This is designed to cut small lines that might tangle in and disable the prop.
Click for larger image
Main Cutlass Bearing

A close-up of the main shaft at the cutlass bearing. You can see some rust and pitting in the main shaft, but the two inches of cutlass bearing wear surface is looking excellcnt.
Click for larger image
Bolts

Large bolts from the couling betweein the propellor shaft and the transmission flange.
1/10/2018
Click for larger image
Prop Shaft

Our main propeller shaft out.
Click for larger image
Corrosion

An Aquamet 22 shaft should last well and show very little corrosion with even extended use. For some reason, this shaft is badly corroded and some of the pits run quite deep. It’ll need to be replaced.

Update 1/15/2018: Although the current Nordhavn 52 specification uses an Aquamet 22 shaft, it turns out back in 2010 Aquamet 17 was used. Understanding its not Aquamet 22, the failure isn’t that surprising. Current-generation Nordhavns will experience much better lifetime.

Click for larger image
Wing Cutlass Bearing

James holding the old wing engine cutlass bearing. You can see at the bottom the inner rubber material has come free from the outer housing of the cutlass bearing so it needs to be replaced.
Click for larger image
Cutlass Bearing Failure

You can see how the cutlass bearing has come apart and the rubber has slipped down.
Click for larger image
Shaft Coupling

The propeller shaft-to-transmission coupling resting in the lazarette. It’s been removed to allow the propeller shaft to be slid out of the boat.
Click for larger image
No Shaft

It looks a little odd in the bilge without the propeller shaft there where it should be.
Click for larger image
Spur Cutter

James holding the spur cutter and talking with Roland Mcildowie and Neil Russel. We’ll need to replace part of the Spur line cutters since an overzealous diver stripped the threads on the zinc attachment. Crated in the trailer behind is our prop shaft, with our old muffler beside it.
1/11/2018
Click for larger image
Gori Prop

Roland Mcildowie of Proteum reassembling the Gori wing engine prop.
Click for larger image
Rudder Foot

We removed the rudder foot to check the bearings. It looks like we’re going to need a new cutlass bearing and a new lower bearing on this stop.
1/17/2018
Click for larger image
E. French and Son

At E. French and Son to pickup a new lower rudder bearing they fabricated. It’s amazing how much machinery they can fit in such a small place.
1/18/2018
Click for larger image
Shaft zincs

James installing the wing engine shaft zincs while Roland Mcildowie installs lock screws to finish off the Gori prop rebuild.
Click for larger image
Spur cutter zinc

James installing the spur cutter zinc on the main shaft while Roland Mcildowie is going to drill a small dimple into each side of the main shaft cutlass bearing to ensure it’s properly secured.
Click for larger image
Lower rudder bearing

Roland Mcildowie of Proteum test-fitting the lower rudder bearing that E. French & Son made for us.
1/22/2018
Click for larger image
Shaft delivery

Back at Saxon Wharf, our new prop shaft just arrived. It had been delayed for several days waiting for an appropriate length piece of metal.
Click for larger image
Shaft install

Roland Mcildowie and Jack Woodford of Proteum installing the new prop shaft.
Click for larger image
Rudder hole

Our rudder has a hole in it to allow a prop shaft to be removed without dropping the rudder.
Click for larger image
Transmission

The prop shaft just about to meet back up with the transmission.
Click for larger image
Bilge

It’s nice to prop shaft reinstalled.
Click for larger image
PSS

Our new Packless Shaft Seal (PSS) in place.
1/24/2018
Click for larger image
Steering Post

Jack Woodford of Proteum installing the rudder upper bearing.
Click for larger image
Lift

Saxon lifted the boat today so we could remove the rudder to replace its cutlass bearing. The rudder cutlass bearing is worn out, which isn’t that surprising given the hours on the boat, but it is strange that the rudder cutlass bearing is worn more than the main shaft bearing. We’ll also paint the places on the hull where the supports were.
Click for larger image
Supporting Rudder

Members of the Proteum, Nordhavn Europe and Saxon Wharf crews supporting the rudder with a pipe while Roland Mcildowie of Proteum removes the rudder foot.
Click for larger image
Forklift

With the rudder shoe off, Saxon raised a pallet into place to support and lower the rudder.
Click for larger image
Lowering Rudder

Lowering the rudder out of the boat.
Click for larger image
Rudder Off

The rudder off. That’s a first for us.
Click for larger image
Rudder Shaft

The rudder shaft appears in decent shape, with little signs of corrosion.
1/25/2018
Click for larger image
Raising Rudder

Raising the rudder into place for reinstall.
Click for larger image
Installing Rudder

Saxon Wharf using a forklift and pallet to slowly raise the rudder into place. Mark, who is running the forklift, has an incredibly delicate touch.
Click for larger image
Rudder Shoe

Roland Mcildowie placing the rudder shoe underneath the rudder.
Click for larger image
Rudder In Place

The rudder is in place, with the rudder foot painted, so we’re ready for launch.
Click for larger image
Launching

Dirona heading back into the water after nearly three weeks. Prior to this, the longest time we’ve even been in the yard is ten days. There’s still some work left to do that’s easiest done left in the water. We’ll move over the Hamble Point Marina and Nordhavn Europe Ltd. will finish it up.
1/26/2018
Click for larger image
Full Throttle

Testing at full throttle en route to Hamble Point is showing some minor vibration from the prop shaft area.
2/1/2018
Click for larger image
Saxon

The prop shaft has 0.023″ of run-out and the current professional assessment is coupler-to-shaft misalignment. Dirona will need to be lifted out of the water and the prop shaft pulled out for everything to be remeasured and refit. So we’re back as Saxon Wharf this morning.
2/2/2018
Click for larger image
Hamble Propellers

At Hamble Propellers Friday morning to investigate the prop shaft run-out issue.
Click for larger image
Both Shafts

To better understand the prop shaft run-put issue, we brought the new prop shaft, the old prop shaft, the propeller and the coupling to Hamble Propellers for inspection.
Click for larger image
Shaft

We might have found the issue with the propeller shaft run-out. It appears there was some metal transfer from the old shaft taper onto the inside of the coupling. Certainly this would have prevented an accurate taper fit.

In the picture of the old shaft you can see a semicircle of metal came off. We don’t know if this is the problem, but it’s certainly a problem.

Click for larger image
Coupling

There is a matching ridge of metal inside the coupling taper that appears effectively welded in place (see red arrow—click image for larger view).

Monday the ridge will be removed, the taper will be lapped in then checked with machinist blue to ensure greater than 80% contact. Then the whole assembly will be checked for run-out on a prop-shaft-jig and then again in the boat prior to launching.

2/6/2018
Click for larger image
Hamble Propellers

Engineers at Hamble Propellers working on our new propeller shaft.
2/8/2018
Click for larger image
Launch

On the lift at Saxon Wharf for launch. The prop shaft is slightly out of true or there is an alignment issue, but we decided that prop shaft alignment perfection was for boaters that don’t want to visit London. Technically, it’s slightly out of ABYC specs but it’s close and we bought the boat to enjoy the world rather than the yard (which was very nice but a month was enough). We’ll align the engine and check runout again in London.

Update 4/10/2018: The prop shaft appears to be running within tolerance and without excessive vibration and all appears to be as it should be at this point. We’ll post an update here after we have had some usage but, at this point, it’s all looking as it should.

Show locations on map Click the travel log icon on the left to see these locations on a map, with the complete log of our cruise.

On the map page, clicking on a camera or text icon will display a picture and/or log entry for that location, and clicking on the smaller icons along the route will display latitude, longitude and other navigation data for that location. And a live map of our current route and most recent log entries always is available at mvdirona.com/maps.

 
 


If your comment doesn't show up right away, send us email and we'll dredge it out of the spam filter.


9 comments on “Cutlass Bearing Replacements
  1. North Baltic sea says:

    Hi, thank you for a really interesting site. I have one question about PSS seals, was it the first exchange for your Trawler? If so, what kind of shape did the rubber look inside if you could possibly look into it? PSS instruction is to replace rubber every six years. I had the same seal NT-37 and thought about replacing when the rubber looks like a new one out and is 9 years old.

    Regards

    NBs-Finland

    • The rubber didn’t appear to be breaking down when we replaced our bellows. There was no obvious or outward signs of degradation but, as you know, that bellows failing would be a very bad thing so we lean to playing that decision conservatively.

  2. Robert says:

    Dear James,
    I have an idea to true the drive shaft casing. I put this idea forward as a junior engineer to yourself.
    I thought you could mill a spiral cut into the old drive shaft taper and use this as a bit to recut the shaft casing.

    Identifyed problems
    1 The old taper many not be a good fit as it is already worn. A new taper may have to be milled.
    2 Consideration must be given not to over drill the taper. Stopping the spiral short of the bit ends should do this.
    3 The benefit of this work may be insignificant. Time may bed the new drive shaft with the casing. To get maximum benefit the drive shaft may need replacing.

  3. Chris Barber says:

    Face-palm! So that’s what the hole in the rudder is for!

  4. Neal says:

    Greetings from Seattle. Specifically, on the hard at Delta Marine, where a few hours ago we replaced a Grade 17 propeller shaft with a Grade 22. The old shaft had a deep ring of crevice corrosion hidden under the propeller on our 1999 Krogen 48.
    Was there any outward evidence that inspired you to inspect the lower rudder bearing? Was the rudder shaft loose in the lower bearing?

    • The loads on the rudder are extremely high and it’s a life critical component so, at 9,500 hours, we decided to take it apart to look for any problems or excess wear. There were no external signs of problems. We just wanted to get a read on how the rudder and related mechanical systems were doing and replace any showing material wear.

      Enjoy your time at Delta. They have earned an excellent reputation for doing excellent work.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.