Vulkan Couplers have an Out-put Bearing in the Housing

Vulkan coupler are one of the most common found on mega-yacht sized vessels.  This torsional coupling is found between the gear box and the engine and serves to dampen the torsional loads coming from the engine flywheel.  A polyurethane element (see second photo) acts as a gear “bumper”.  This particular Vulkan model was removed from a 87′ Ferretti with a ZF v-drive gear box and a Spicer cardan shaft.

The call first came in when a distinct thump was heard from that engine.  The diesel mechanics checked out their end and determined it was int he drive train.  That is when we get the call.

It was apparent that something was wrong when you could stand over the engine side of the cardan shaft and lift the assembly slightly – a worn bearing.  With this version of a Vulkan there is a large bearing that is part of the bell housing assembly.  This supports the weight of the u-joints on the cardan.

Vulkan Coupler Torsional dampening element

The Cardan and Vulkan have considerable weight and were, of course, in some tight places.  You could say this job took more brawn than brains.

The job does require the right tools and training.   The flanged coupler in the first photo must be removed from the shaft in order to replace the assembly on the housing.   The coupler is hydraulically fit on the shaft.  To remove and replace requires a high pressure pump and the right fittings.  Any other removal process (force, heat) will definitely damage the assembly beyond repair.

Vulkan Couplings – another High Seas Yacht Service specialty.

A Fluiten shaft seal in two halves on the bench

We have just finished a complete shaft system on an 87′ Ferretti that had a unique shaft seal system from Italian manufacturer Fluiten.  The Fluiten shaft seals are part of the “face seal” family.  There are two main parts to any face seal system; the stationary body (right side of pictures) that is bolted to the stern tube and the “rotary” piece (left side) that is attached to the shaft and rotates.  The Fluiten relies on a pre-loaded spring in the stationary unit to keep constant pressure between the halves preventing the sea water from coming in.

During shaft maintenance all components need to be inspected.  With Fluiten shaft seals there is a small phenolic ring that is allowed to wear with time similar to a brake pad.  This version of the seal has the wearable ring on the rotating half.  However, other models from Fluiten have the wear ring on the stationary half.

The ring specification is 2 mm minimum before replacement.

Measure the wearable phenolic ring for proper thickness

Make sure your service provider is checking all of the manufacturer’s specifications.  Not all companies will go to this length.  Reassembling the boat with a wear item that is past its life is a disservice to you and potentially dangerous to your boating experience.

It doesn’t take any training to see the bends in this pair of struts.  The shafts and props tell the full story – a hard grounding.

The machine shop will straightened the shafts after determining no cracks.  The prop shop will recondition the props.  We attempted to straighten these struts by a variety of set-ups in our H-press and straighteners.  Unfortunately the metal memory was hard to overcome.  Next we brought in some heat to move the process along.  After a great deal of care and many attempts to move the struts the inevitable occured – with a loud bang.  The strut cracked.   That condems the struts to scrap metal.  We gave it a good shot but the customer knew the likelyhood of savings these struts was minimal.