Finding the Engine Overtemp Problem

Engine Gauge Display after Engine Warmup

Removed some paint between the engine block and it's ground wire.  Then applied aluminum antisieze to all the surfaces.  The water temperature gauge now reads  (sort of) correctly 190°F vs. 180°F.

Fuel Injector Leak

Looking Up from Underneath the Fuel Injection Pump

Nellie has been leaking a little fuel (enough to wet-out a napkin in a 50 mile run) somewhere near the injection pump's distribution lines.

A small drop of fuel can be seen hanging from the injector tube support bracket.  The likely culprit is a loose connection or bad washer between the injection tube and the pump.

Cummins 4BT Water Pump

Telltale of a Leaking Water Pump 

During the morning engine check I found that the water pump's shaft seal had started leaking.

I replaced the pump with a used spare we had on board. A few days later I purchased a new one at NAPA for $54.

Trying to find a water pump for your 4BT3.9M? At an autopart's store tell them you've got a 1991 Dodge D250 w/ 5.9 Cummins turbo.

The Cummins parts catalog for the 4BT3.9 lists the following for water pumps: 3802004 and 3913432.

3802004 crosses to a NWP 557145 in NAPA numbers.

3913432 crosses to a TFP 41181 in NAPA numbers.

Conductive Grease

Years ago a friend at the Long Beach Naval Station gave me some conductive grease.  He said it was commonly used to both seal out salt air and improve the conductivity of electrical contacts.  I've been looking for the stuff ever since.  

Today, while putting (aluminum based) antisieze on the raw water pump's bolts it dawned on me that this is what the Navy electricians were using.  I put an Ohm meter across some of the stuff and sure enough, it's conductive.

A Closer Look at the Rudder Post Cutless Bearing

I've been wondering why there's a cutless bearing, or what at first glance appears to be a cutless bearing, in the rudder post.  Perhaps the yard's purpose wasn't additional support, but rather to aid in the installation of the rudder post tube.  Specifically, they wanted to keep the post centered, within the post tube, while the post tube was being fiberglassed into the hull.  Here's a picture of an installed post tube.  It's 7" long (1" of that protrudes outside the hull), with a 2" ID and 2-1/2" OD).  

The Fiberglass Post Tube Penetrates the Hull and is Fiberglassed Into it.  A 7-1/2" x 2-1/2" Hose (Not Shown) Connects the Post Tube to the Packing Gland.   The Metal Retainer, Seen above the Post Tube, Keeps the Lower Part of the Packing Gland From Moving When the Upper Part of the Gland is being Tightened.

I imagine the yard installed the rudder posts something like this.  Drill a hole in the shoe and install the gudgeon.

The Shoe's Gudgeon (or Lower Rudder Post Bearing)

Next, mount the rudder post's upper bearing in the lazarette.  

The Upper Rudder Post Bearing

Next, drill a 2" hole through the hull on a line between the upper and lower bearings.  

Next, slide a 1-3/4" rudder post through the upper bearing and then through the hole in the hull.  Before seating the post into the gudgeon, slide the post tube onto the post.  Push the post tube against the hull and draw a line on the hull at the intersection of the post tube and hull.

Remove the rudder post and cut along the line on the hull.  Now, finally, install the rudder post and post tube again.  Slide all but 1" of the rudder tube into the hull and fiberglass it into to the hull.  And there you have it, a perfectly aligned rudder post and rudder post tube.

A Piece of Rubber Emerging from the Rudder Tube

In conclusion:  The rubber that we've seen coming out of the post tube for years isn't part of a cutless bearing.  The rubber was there to make sure that there was a tight fit between the rudder post and the rudder tube during construction.  Once the fiberglass had set the rubber was superfluous.

Rethinking the Intermediate Bearing's Barbed Fitting

Here's what Nellie's fitting looked like after it was removed for inspection.

Nellie's Barbed Intermediate Bearing Fitting

They say a picture is worth a thousand words.  Well, here's a picture.

Nellie's Barbed Intermediate Bearing Fitting

The fitting crumbled yesterday during reinstallation.  Mike McCoy, Tug E. Bear 37VT62, warned that these fittings might be brittle.  How right he is.  

For the record, the fitting is 3/4" NPT and 3/4" barbed.

It was replaced with a poly fitting of the same dimensions.

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."