High Seas Yacht Service » Feadships

Replacing Soundown Coupling Thrust Element

Chris — Mon, 01 Feb 2010 11:46:35 +0000

: Soundown Thrust Element – Old Deterioration vs. New

Soundown Vibration Dampening systems are usually found on older large yachts. This one came out of a 123′ Feadship. The center stud has two urethane “Coupling Thrust Elements” that have a finite life and should be checked every 10 years. The Thrust Element in the photo was 50% deteriorated and came out in small pieces. The picture shows the remnants on the bolt washer and in the part. The new urethane part is also shown in the picture.

Replacing these elements is not a simple task. The Soundown and spool combination weighs over 250 lbs which presents certain challenges when hoisting out of a bilge and carrying through a yacht’s interior. The center bolt requires 1,150 foot pounds of torque by specification. We must bolt the Soundown to a bench in order to apply the right torque (using a torque multiplier). Setting up the Soundown properly and applying the right torque requires removal from the vessel and work in our machine shop. We find it impossible to get the right set-up and leverage in the bilge or engine room.

If another yard is performing this Thrust Element change in your engine room make sure they are applying the right torque to the center bolt. If they are – and have figured out how to do this without taking it out of the vessel – please send me a quick email. My mechanics do not appreciate the health benefits of the workout required to haul 250 lbs out of the boat.

WATER COOLED Cutlass Bearings

Chris — Thu, 21 Jan 2010 13:39:55 +0000

Stern Tube Cutlass Bearing Completely Worn

Here is another case of poor water cooling for a cutlass bearing. This cutlass bearing came out of the forward end of the stern tube on a 123′ Feadship. The cooling line that runs to the stuffing box keeps the packing cool and provides water to the two cutlass bearings located in each stern tube.

Unfortunately, the cooling line was blocked closer to the engine and the stuffing box and bearing ran dry for a short period of time. It does not take long to completely wipe out a cutlass bearing when running dry.

Since the vessel is now in the yard for more extensive service we are removing the running gear from both sides (three shafts per side coupled by SKF Hydraulic muff couplers) and performing a complete engine alignment.

Looks like we will need a few more of the large sleeves for the SKF Muff Couplers (as seen here on a past project).

SKF Muff Coupler Wrap – Huge Shrink Sleeve

Chris — Tue, 18 Aug 2009 00:26:07 +0000

A finished shrink sleeve on an SKF Hydraulic Coupler

: SKF Steel Muff Couplers need to be sealed from sea water with shrink sleeves

SKF OKC Hydraulic Muff Couplers come in steel and stainless steel versions. The majority that we come across are steel even though they are submersed in salt water. Older installations attempted to keep the water out by wrapping the coupler in fiberglass.

SKF developed a shrink sleeve for each of the coupler sizes. This sleeve wraps tightly around the coupler and shaft and seals the part water-tight. This shrink sleeve process was completed in less than a half hour using a large propane torch. Thanks to our friends at South Cross Boat Works (another LMC Lauderdale Marine Center on-site contractor that specializes in shrink wrapping and scaffolding) that use large propane torches for shrink wrapping boats. It is nice to use the right tools for the job.

This is the finishing touch on completing the 131′ Feadship project.

SKF OKC Hydraulic Muff Couplers – Handle with Care

Chris — Mon, 17 Aug 2009 23:46:19 +0000

SKF Hydraulic Muff Coupler on 5.5" Shaft

Over the past few weeks we have had the pleasure of working on a classic 131′ Feadship. This yacht has 5.5″, three-section shafts with two sets of hydraulic muff couplers (four total). The hydraulic muff coupler manufactured by SKF can be incredibly simple if everything goes well. Removing or installing a hydraulic coupler requires two different hydraulic pumps – one high pressure and one low pressure. The high pressure pump is unique – up to 40,000 psi which requires special high pressure fittings and a great deal of safety precautions. High Seas has the right tools for this job.

The hydraulic coupler installation requires an exact fit and a light touch between the steel coupler sleeve and the shaft ends. There are no fasteners in this system – no bolts, no keys or key-ways. Approximately 7″ of shaft ends that are inside the coupler must be machined to within tenths of a millimeter to the coupler sleeve. This particular sleeve was manufactured to 139.7mm (not 140mm) to give you an idea of the tolerances. No burs or other imperfections are allowed. Mistakes during installation can result in small burs that will destroy the coupler when the next yard tries to remove it.

Our thanks to Steve at SKF for his outstanding customer support. Steve coordinated the expediting of SKF parts for this project and was a wealth of knowledge on a few technical questions. While we have experience working with hydraulic couplers we are also always open to speaking to the company experts to make sure we are taking advantage of all the tricks and knowledge in highly unique parts.

Hydraulic Muff Coupler - the long view