On The Hard Again: Getting it Straight - The Fix

Reader Note: This article deals with the resolution of the port running gear alignment problem. To fully appreciate the story you should read "Getting It Straight - Background" to understand the scope and complexity of resolving this problem.

The project's objectives:

• To achieve running gear alignment within 3,000th of an inch (.003")
• To determine, with certainty, the root cause of the coupling failure

Without finding the smoking gun that caused the coupling failure, the alignment problem is not likely to be solved. This was the case with the two haul-outs in March and April.

In order to achieve this objective, it was necessary to examine every component starting from the front of the engine and work backwards to the nut the secures the propeller to the shaft. This includes:

• The engine mounts
• The Evolution Marine Coupling
• The shaft
• The Tides Marine Shaft Seal
• The hull cutlass bearing
• The strut cutlass bearing
• The propeller

Along with that, I needed significant technical expertise. These are the key players: 

• Engineer Chris Murray from Soundown, the company that built the coupling
• Top flight Cat technician, Guy Crudele, from Guy Crudele Repairs, a Caterpillar Authorized Marine Dealer
• Rose Marine, a commercial boat yard capable of hauling the boat and supporting the project. 

Now to the story,

On Monday, June 12, I cruised the boat from Hingham to Gloucester arriving at Rose Marine's haul-out bay at 12:30 PM. The boat was immediately lifted, power washed and by 3:00 PM was blocked and sitting on the hard.

Guided Discovery on the Travel Lift ready for transport into the yard

Rose Marine Hardware and Office

Work began promptly on Tuesday morning. By the time I arrived on the scene the port propeller and shaft had been removed. The project was off to a good start. The shaft was on its way to the machine shop.  The propeller was awaiting transport to the prop shop. Guy was in the process of disconnecting the coupling while Jeff, his assistant, was starting the routine maintenance projects on the engines transmissions and generators.

Guided Discovery blocked on the hard early on Tuesday morning
Guy Crudele's truck is pulled alongside
Notice the port shaft is missing
Notice the white spaces along the waterline where the lifting straps prevented power washing

Removal of the shaft was necessary to determine whether it was "true." This crucial step was not done during the haul-outs in March and April. We assumed that if the propellers were not damaged, then the shaft should be OK.  In fact, Bob, at Admiral C&B Propeller, stated that upon arrival at his shop, "the props had no signs of a hard grounding." Admiral did perform edge work to remove minor imperfections and tuned the props to make them, to quote Bob, "better than new out of box props."

Explanatory Note: We had a VERY soft grounding in November 2015 at the Big Pass sandbar. I was able to easily back the boat into deep water. Because the props are positioned well above the keel it is unlikely that they touched the bottom. My divers at Sarasota, and next year in Hingham, reported no damage to either prop. They did report missing paint on the bottom of the keel but, fortunately, no damage.

63 profile showing propellers positioned well above the keel

If the props were not damaged by the grounding, then the question arises as to whether the engines were properly aligned during the build and whether the shaft itself was true at the time of its instillation. The Evolution Coupling started shredding rubber at approximately 1,000 hours. If the engines were slightly out of alignment or the shaft was not true, then the failure of the coupling was attributable to misalignment. 

Port propeller removed awaiting transport to the prop shop

Wednesday, a Rose Marine technician removed the cutlass bearings from the hull and strut. The bearings show a pattern of elliptical wear.  The elliptical wear confirms the motion Chad, Randy and I observed at the power takeoff and shaft seal along with the leak at the lip seal during the sea trial in April. This motion and the leak prompted Chad to declare failure with regard to the alignment.

Port strut and cutlass bearing prior to removal

Hull cutlass bearing prior to removal

Close up of the strut cutlass bearing
The wear pattern indicates a bent shaft causing an elliptical motion

View of the port transmission flange (just below the power take-off that runs the hydraulic system)
It's Tuesday morning. The coupling has been removed and delivered to Soundown for inspection

For comparison. View of the starboard side coupling, lip seal carriers and shaft seal

Coupling bolts, shaft seals and shaft seal carriers

View of the port shaft seal. Notice the brown trail caused by water leaking
The leak at the shaft seal was the tell-tale sign that Embree Marine Services' alignment in April was unsuccessful

Tool used to remove the strut cutlass bearing

The hull cutlass bearing cut out

New hull cutlass bearing installed

New strut cutlass bearing installed

Jeff from Guy Crudele Repairs working on the concurrent maintenance projects

Photo of a shaft being worked on at the Rose Marine machine shop

Dummy coupling fabricated by Soundown
This "tool" is the key to the alignment project

The propeller was sent to the shop for computer scanning
Guy Crudele was making sure that every component was machined to exact tolerances 

The port propeller was returned on Friday. The prop shop reports showed that the propeller met ISO 484 Accuracy Class of S - Very High Accuracy. ISO 484 defines the manufacturing tolerances for marine propellers. Both the "Initial" and "Final" Reports met the ISO "S" standard. The tolerances for the four blades were essentially unchanged from the prop work performed by Admiral in March. Bottom line. Damage to the propeller or torque distortion caused by blade misalignment ruled out the propeller as the cause of the misalignment or the damage to the coupling.

Frank Rose using a fork lift to assist Guy in positioning the shaft for installation
The 2.5 inch 15 foot stainless steel shaft weighs in excess of 300 pounds

Now, we come to the shaft. The machine shop reported that the shaft was bent 10,000th of an inch and that the bend was forward of the strut bearing. Since contact with the bottom or a foreign object was ruled out, the distortion in the shaft was the result of misalignment. Something caused the shaft to bend and the most likely cause is misalignment of the engine.

Guy Crudele installing the shaft

Frank and Guy pushing the shaft into position
This was the first big test of the alignment of the cutlass bearings
The shaft slid into place smoothly.  First test passed

Friday afternoon. Soundown has delivered the re-manufactured coupling
Chris Murray turned this project around in three days

Now let's talk about the coupling. Keep in mind the history here.

• October 2016. New coupling purchased from Soundown (Cost $2,760)
• March 2017: New coupling installed after the 2.75" flange is replaced with the 2.5" flange from the original coupling
• March: The original coupling sent back to Soundown for re-manufacture
• April: The re-manufactured original coupling is shipped to Embree for installation 
• April: The new coupling is removed and shipped back to Soundown
• April: The new coupling is checked for damage and a 2.5" flange is installed. Unit is tagged and stored atr Soundown for my eventual use on the starboard side.
• June 13: The original coupling shipped to Maine for examination.
• June 13-16: The original coupling is re-manufactured due to extensive damage sustained on the 200 hour run from Sarasota to Hingham

Recall that the coupling was removed on Tuesday morning and delivered to Soundown's manufacturing facility in Maine. Recall also that part of the coupling's job is to compensate for minor miss-alignment. The technician at Soundown reported that the coupling had been subjected to radical forces. A steel shaft within the unit that measures 2 inches in diameter by 4 inches long was bent 45,000 ths of an inch. Soundown had never seen such severe damage.

Special aluminum tool fabricated to lock the shaft in place when it is slid back
  in the water to swap out the Dummy Flange for the coupling

The shaft connected to the Dummy Coupling
The Tides Marine Shaft Seal is in the lower right hand corner of the photo
The Dummy Coupling facilitated a precise alignment.
The process of aligning the running gear involves physically moving the engine

The "shaft lock tool" is put in place
The shaft has to be moved backward in the water to remove the Dummy Coupling
The tool prevents the 300+ pound shaft from slipping backward and damaging the rudder

Jeff spray painting the port running gear on Friday afternoon

Remember the white patches along the hull where the slings prevented power washing
I had Rose Marine repaint the waterline and chines to get rid of the white patches (not yacht)

Guided Discovery being launched at 7:45 AM on a foggy Saturday morning

Guided Discovery operating on the starboard engine is en-route from Rose Marine to Pier 7 Marina
The aluminum  Dummy Coupling on the port side cannot deal with the torque needed to turn the shaft

Heading to Pier 7 Marina on a foggy Saturday morning on one engine

I pass the fishing trawler that was blocking the travel lift of Monday. Notice that it is listing to starboard.
Story I heard was that an engine had been removed. That would easily account for the starboard list

Jeff waiting on the dock at Pier 7 Marina
The final stage of the alignment occurs in the water

Guided Discovery at the dock at Pier 7 Marina
Guy Crudele is already hard at work completing the alignment
I spend 7 hours washing the boat

The last stage of the alignment occurs in the water. Once the Dummy Coupling, propeller, shaft and cutlass bearings are installed, the boat is launched and given time to "settle out." While on the hard, the hull is subject to forces from the blocking and jack-stands the substantively effect the alignment.

Now that we were in the water and tied to a dock the final phase of the alignment began. This involves performing the alignment with the shaft married to the Dummy Coupling. The initial reading according to Guy was that the alignment was out of tolerance by 27,000 ths of an inch. Time to move the engine.

All the facts thus far point to the alignment of the engine as the cause of the misalignment and the damage to the coupling, shaft and shaft seal. Remember, the engine is aligned to the shaft rather than the shaft being aligned to the engine. The Cat C9 engine weighs 1,500 pounds and is physically attached to other systems like exhaust and fuel (not easy to move). The process involves loosening the engine mounts, moving the engine with a pry bar and constantly checking tolerances with a feeler gauge as the mounts are locked down. 3,000 ths of an inch (.003") is within tolerance.

Guy achieved 2,000 ths on an inch (.002"). At that point, the Dummy Coupling was removed and replaced with the re-manufactured Evolution Coupling. We did a brief sea trial while tied to the dock. Essentially, the boat is put in gear and strains against the lines holding it fast to the dock. Believe it or not this actually works. Randy Cornett and I did this at Marina Jack. We could see the water leaking and the perceptible motion at the power take-off even with the engine at idle. Guy observed no motion or leaking. The final proof was the 4 hour run from Gloucester to Hingham. Upon arrival I checked the absorbent pad under the lip seal. It was bone dry. SUCCESS!

Illustration showing a rear engine mount in relation to the shaft and coupling

Rose Marine fuel barge approaching

Rose Marine fuel barge tied alongside after pumping 930 gallons into my tanks
Rose charged me $1,87 per gallon. The lowest price I've ever paid for diesel

Completed project after running 4 hours on Sunday back to Hingham. Notice that there is no water leak

The port engine starboard aft engine mount
Alignment required physically moving the engine
Notice that Guy has painted the engine mounts
Guy left the engine room spotless

Outside of some monumental expense, this has proven to be a very satisfying exercise. I worked with some phenomenal people, Chris Murray, Guy Crudele and Frank Rose who worked together to make this repair happen successfully. In total the boat was on the hard for 5 days. The entire project was completed in six.

Thank you to all!

Written by Les