Tiara 52 Runs Smooth

Another 50′ Tiara came to us with a vibration problem that was diagnosed as shaft whip.   This particular model has too much distance between the strut bearing and the v-drive engine.  This is exactly the same problem encountered and posted on another Tiara last year.

The solution is fairly simple – add another cutlass bearing to the stern tube.  However, this can only be done if the latest alignment technology is used.  Not all struts are aligned perfectly to the stern tube.  You can get away with less-than-perfect strut alignments if there is no bearing in the tube and the engine is aligned properly.  This is seen all the time when a shaft is not going through the center of the stern tube. 

With the addition of a cutlass bearing, the alignment is critical.  On this project we did find one of the struts to be out of alignment to the stern tube.  Therefore the strut had to come down and be realigned properly.  While the Optical Scope system was set up, both v-drive engines got a precision alignment. 

Tiara with a Strut Removed

V-drive alignments can be very complex.  With the output coupling under the engine, the adjustment to the engine mounts can be intuitively opposite.  It is very easy to get confused and move further out of alignment.  Fortunately the Optical Scope simplifies the process and gives absolute confirmation when the engine is aligned properly.

Of course, the project was not complete until the customary sea-trial.  All was smooth and the customer was very happy.

The vessel is now for sale and the listing broker is promoting the difference between a High Seas “fixed” Tiara and others still on the market.

If you have a shaking Tiara please give us a call for a free inspection and quote.

Creative PhotoShop work on a Classic Rybovich

You may have already seen this picture in circulation and we need to clear the air.  This was a little humor along with some creative work on Photoshop. 

This 1974 Classic 75′ Rybovich Motoryacht (one-of-a-kind) is meticulously maintained by her owner and is very “original”.  During a recent haul-out for repower and transmission work we re-aligned the struts and will finish the engine alignment when everything is done in the engine room.

Thanks for all the “kind” words of encouragement from those that thought we suggested destroying a Classic.  Also, I do not plan on engaging in a debate on the merits of Mercury vs. Yamaha in this application.

Float aligning a cutlass bearing in a strut

In past posts we sea-trialed a 120′ Intermarine and observed a bad vibration with the vibration analysis expert and took a video of the obvious problem as seen on an aft cockpit table.

That was the case with a recent 120′ Intermarine that had a vibration problem.  During the sea trial is was apparent that the shafts and props needed significant work.  There are many different vibrations that can be felt and heard:  shaft hopping, propeller distortion and cavitation are just a few sources.  With this vessel we could feel the shaft hop and see the Tides Seal movement in the engine room – a clear sign of bent shafts and a misalignment.

Some vibrations are subtle and some are very bad.  This one ranks in the very bad category.  The video was taken during the sea trial.   We were about 2 miles off Fort Lauderdale in FLAT CALM SEAS.  Once the Captain pushed up to 1800 RPMs the vibration was obvious.  Everything in the aft cockpit was shaking and moving.  There is no way someone could sit around the tables  in the aft deck during a cruise.  A water bottle placed on the table shook and would walk off the table within 10 seconds.

The vessel was hauled and we are starting the disassembly process.  Stay tuned for updates on this vessel in future posts.

Roger working engine mounts during an alignment

We recently got a call from a 90′ Johnson that just finished the seasonal migration from Newport to Fort Lauderdale.  The Captain reported a starboard side vibration that was clearly visible in the engine room as a shaft “wobble” while underway.

Centa series Centax L Coupling

Centa flexible couplings are found on larger vessles that have remote transmissions installed and aligned seperately from the main engines.  This particular vessel, a 130′ Alloy, was hauled out for an extensive dry-dock period.  The props had suffered some grounding damage and it was time for a running gear check.

A typical job for High Seas; shafts out and checked in our on-site machine shop Straight Line Marine, replace cutlass bearings, service the Kobelco Eagle seals (as mentioned in a prior post) and an Optical Scope Alignment check of all bearings and transmission locations.  Both transmissions required a minor alignment to square up to the shaft line.

With remote ZF transmissions the process requires removing the Centax L flexible couplings and adjusting the ZF mounts.  This particular vessel had adjustable mounts which is easier than the typical hard-mounted, chockfast arrangement.

Once the ZF transmission was aligned the engines required an alignment to be within Centa’s specifications for the flexible couplings.

Once everything is aligned the Centa couplings are reinstall paying strict attention to the manufacturer’s torque specification.  It is also important to install the “Links” (left part of the picture above) in the proper direction given the engine rotation.

Optical Scope alignment of ZF transmission with Centa Couplings on the ground

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.

Milled Strut Base Plate for Alignments

On a recent strut alignment on a Cheoy Lee we ran into a situation with bottom clearance.  The vessel unfortunately sat on the bottom and the upward pressure caused the strut to bend or bow.  We dropped the strut and straightened it in our machine shop (see prior post).  Re-hanging the strut in the right aligned position requires a level of precision to get it right.   Once the strut pocket was cleaned and the strut was dry-fit for a test alignment we realized that the imperfections in the original strut casting left humps and hollows.  The high points contacted the hull in the wrong spots and prevented us from adjusting the strut to the right position.

The solution – mill a small amount off the strut pad – approximately 0.050-0.075″.  Not enough to cause any concerns with the integrity of the strut.  As you can see in the picture the original pad had plenty of beef.

Once properly aligned and assembled the vessel was launched and we went for our traditional sea-trial.  I always like to sea-trial a vessel to make sure it is vibration-free and the customer is satisfied.  It is also the right time to ask for a reference, which this Captain gladly allowed.

During our disassembly we measured the distance from the single cutlass bearing in the strut to the coupler on the transmission.  We found the distance far exceeded the recommended distance between bearings as calculated in the Aquamet Crucible guide.  Any vibration from a misalignment or bent shaft would be exaggerated by a shaft whip condition.  Our solution – straighten the shafts, align the motors and add a half cutlass bearing in the stern tube.  Not a complicated or expensive solution.

The results speak for themselves.  It only took a few minutes of sea-trial running the boat at cruise and WOT to feel a big difference in the smoothness of the ride.

Another happy customer and problem solved.