Intermediate Bearing's Hose Fitting

As this LNVT blog post states, several tugs have found their intermediate support bearing's hose fitting to be badly corroded.

Tug E. Bear 37VT62's Badly Corroded Fitting

Today I inspected Nellie's.  It looks old but there is no evidence of corrosion. So, it's serviceable.

Nellie's Intermediate Bearing Hose Fitting

 I suspect that Nellie's is a factory original part as it's made the same (unusual) way as Tug E. Bear's.  Removing it will require a plumber's wrench and some luck.

It is curious that the intermediate support bearing isn't bonded.  Perhaps the shaft's bonding protects all the metal in the intermediate support bearing.  

Did LNVTs Come with a Rudder Post Cutlass Bearing?

A Bit of Black Rubber can be Seen just Above the Rudder Flange

The LNVT community has reported odd bits of rubber emerging from inside the rudder post's tube.  I've seen the same thing on Nellie.  

This Large Piece of Black Rubber Came Out

of the Rudder Post Tube

In fact, the last piece of rubber to emerge from Nellie hints at what it was used for: a cutlass bearing.  The evidence?  The rubber's crenellations.

The rudder post is firmly supported on each end: at the top by a roller bearing just under the stern deck and, at the bottom, by a seat in the shoe.  Hai-O and OEY also fixed the packing gland rigidly in place (akin to the intermediate bearing on the prop shaft).  Now it appears they also included a cutlass bearing.  One thing is for sure, with all these supports the rudder post isn't going to wobble.

In a conversation with a builder I was bragging about how overbuilt our house is; double sized beams and rafters are used throughout.  He looked at me nonplussed and said, "Good engineering is about using the minimum material to do the job."  Ouch.  This statement is equally true for an LNVT's rudder post supports.

The upper and lower supports alone are enough to do the job.  Add in the extra support offered by the packing gland and the cutlass bearing really is superfluous.  

Thoughts on Bottom Paint

2017 Bottom Paint

We painted the bottom today. Last year we painted it a not-so-yar baby blue. What can I say, I got a good deal on the ugly on the ugly color.

2018 Bottom Paint

This year we wanted to revert back to good ol' black. I ordered 3 gallons of black Interlux ACT from Overtons.com. Guess what? In lieu of black they sent me, drum roll please, blue! At least it's not baby blue.

For 2019 I'm debating whether to put on any new bottom paint.  Here's the thinking.  We'll haul Nellie in September 2018 and not power wash the bottom.  The first layer of ablative paint will be dust by the Spring of 2019.  Wipe it off (or don't) and go cruising.  According to Interlux, ACT has a "flexible application schedule--paint in the fall and launch in the spring."  So, as long as there's paint, let it keep doing its job.  Worst case is we haul somewhere along the line and do a bottom job.  

Missing Barrier Coat on the Rudder

The stainless rudder has a tendency to sluff off its barrier coat.  Fortunately, it's a simple matter to put more Interlux 2000E back on.  I put barrier coat on the tug's underwater metal surfaces (rudder, propeller, and thru-hulls) because it insulates them from the copper in the bottom paint.  This keeps the bottom paint's copper from reacting electrically with the underlying surfaces and thus gives the bottom paint better longevity.

Bottom Paint Covers All the Metal Surfaces

New VDO Coolant Temperature Sending Unit

Installed a new VDO coolant temperature sending unit.  This one both measures the water temperature and sets off an alarm above 205°F.  The sensor is grounded to the engine through the threads so no teflon tape was used.  Hopefully the MPT fitting alone is enough to stop any leaks.

VDO 323-098 - 1/2-14 NPT - Spade - 205F+/-5F - Single Channel 250F / 120C Temperature Sender

The cooling system was drained of about four gallons of antifreeze before the old sensor was removed.  Removing this much antifreeze and then replacing it is invariably a messy job.

The new sending unit is about 1/2" longer than the one it's replacing.  It's long enough that I worried about it bottoming out on the thermostat.  A few measurements showed that as long as four threads could be seen on the installed sending unit, there would be clearance between the bottom of the sending unit and the thermostat.

All that remains now is to start the engine, check for coolant leaks, and confirm the temperature gauge works.

Reflections on Power Washing the Bottom

Seven Months Later No Green Slime

Last fall, after hauling, I elected not to have the bottom power washed.  Not because I have anything against power washing, but rather because I object to paying $200 for a 15 minute job.  I had second thoughts, however, shortly thereafter because as the green bottom slime dried it curdled the ablative bottom paint into a dried-mud-looking patchwork.  Attempts to scrape the bottom clean were futile.  With visions of having to sand the whole mess off in the Spring we left Nellie for her Winter hibernation on the hard.  The intervening seven months gave me plenty of time to ponder the fateful no-power-wash decision.  The saying "penny wise and pound foolish" came to mind.  It was thus with some trepidation yesterday, after returning to Nellie, that I surveyed the hull.  To my great relief the dried-mud-looking patchwork had turned to dust.  Nothing more than a light washing will be required before applying the new bottom paint.  This whole ordeal brings to mind another saying, "Worry is a down payment on a bill that may never come due."  

Revisited: Cummins Water Temperature Sending Unit

I ordered and installed the following:  

VDO 323-478 - 1/2-14 NPT - Single Channel - Floating Ground Ground 250F / 120C Temperature Sender

It works fine but, it doesn't support an over-temperature warning alarm. 

The unit below reads temperature and grounds-out the alarm lug when the temperature exceeds 205°F. 

VDO 323-098 - 1/2-14 NPT - Spade - 205F+/-5F - Single Channel 250F / 120C Temperature Sender

Since 'grounding of the alarm lug' is exactly how the Cummins 4BT low oil pressure alarm works, we can connect the over-temp lug to this circuit.  Now the low oil pressure alarm will also sound when the engine's cooling water goes over temperature. 

VDO Sending Units

Nellie's water temperature gauge has recently started reading 210°F when the IR temperature gun is reading 180°F.  To say this is disconcerting is an understatement.  Here's my temporary solution.

Yep, just cover the darn thing with a piece of paper. 

Another anomaly has to do with the oil pressure gauge, it's reading about 5 psi low and the needle is quaking.

The Cummins 4BT-3.9M came equipped with VDO instruments.  Among Nellie's spares is a VDO water temperature gauge.  I suspect it's there because a former owner bought it while diagnosing a sender unit/gauge problem.  The sending unit was at fault so the gauge became a spare.

I've ordered new water temperature and oil pressure sending units in the hope that they'll fix Nellie's problems.  

eGauges.com

P/N 360-009 VDO Oil Pressure Sending Unit
P/N 323-478 VDO Water Temperature Sending Unit