Thursday, May 31, 2018

Crowd-Sourced Bathymetry Is A Reality!

I've written about this before here, and here.  But now...

It is a reality!

Today, NOAA announced the end of testing phase in the development of a new crowdsourced bathymetry database!

And some of the first application of data is of interest to PNW boaters - the Canadian Hydrographic Service used this dataset to update several charts of the Inside Passage!


Saturday, May 26, 2018


Blind Bay peace
It's later than many years, but we are, finally, off the dock.  I am typing this at anchor in Blind Bay, one of our favorite anchorages.  It is another wonderful, sunny, quiet day here.  In order to get here tho, this list had to be accomplished:

  • Change the oil in the main engine
  • Change the pencil zinc in the main engine heat exchanger
  • Change the oil in the genset
  • Top up the water in the batteries
  • Locate, acquire and install a replacement fitting for the main engine expansion tank.  It seems like most years there is a major winter project - this was this year's.
  • Dive on the prop and clean it; change the prop nut zinc
  • Clean up the dinghy from the winter
  • Clean up the boat from the winter
  • Remove and store the extra "winter" fenders and lines that we install to weather the winter storms
  • Fill the water tanks (300 gal)
  • Check the fuel (we're good - both are half full)
  • Test the anchor windlass
  • Check the dinghy motor fuel
  • Reinstall and test the dinghy motor
Oops... Tho we had all winter to do it...

Typically, we remove the dinghy outboard and store it in my shop over the winter.  And then getting ready for the season, I clean it up, paint the rusty spots and test run it.  But this season?  Well, I never seem to have gotten around to taking the motor home.

When I tried to start the dinghy outboard, it was dead.  A preliminary investigation showed that there was no spark.  Installing a new spark plug didn't fix it, leading to pretty much the only other likely conclusion: the points in the magneto are fouled.  To get at them, the flywheel must be removed.  Tho I have a lot of tools aboard, I don't have what it would take to do that.

So: decision time... do we go even tho we don't have a functioning motor on the dinghy?  Well of course!

So here we are, peacefully at anchor, with a rowing dinghy!  And tomorrow we will fulfill our annual tradition of listening to the Indy 500 at anchor.


Monday, May 14, 2018

Runaway Starter

Starter motors are not designed for continuous service - they are not provided with any cooling capabilities.  This is because the design expectation is that they will see only intermittent service.  They are high-current, high-power devices however, especially the ones that are expected to crank diesel high-compression engines.  Now hold that thought...

A recent discussion on The Retirement Project bears review here.  It seems that when TJ went to start his engine, the engine start push button stuck, leaving the starter motor running continuously after the diesel had started.  Because of the lack of cooling, a runaway starter motor is a serious problem - aside from destroying the starter, a fire could result.

I recall an incident where a young woman pulled into a gas station where I was refueling my car, and proceeded to fuel hers.  Her starter motor was running, after she shut down her engine (presumably it had been running since she started her car...).  Running, but running poorly - the heat buildup had caused the armature to swell and it was dragging on the field poles, creating more demand for electricity and even more heat.  I opened her hood and found the battery lead to be red hot, smoking, with all the insulation burned off.  Remember, this was at a gas station, where this car (and mine!) were actively taking on fuel.  I shut off the fuel feeds to both cars and then used a tire iron to break the red-hot wire (easy - copper is soft when it is red hot).  The cause?  Welded contacts in the starter solenoid.

One time when driving (I was 17 at the time) my father's 1959 Oldsmobile, the same thing happened to me.  Again, the tool of choice was a tire iron, and I used it to try to pry the battery connection off of the battery.  And failed.  Instead, the post and part of the battery plates came out of the top of the battery, complete with plenty of sparks and acid.  In retrospect, it is lucky I didn't get to experience a hydrogen explosion.  Again:  the cause was welded starter solenoid contacts.

I guess it is not surprising that this happens - these contacts carry prodigious current - 75 - 100 amps in a car engine and more for a diesel, and are connected to a very inductive load.  When they are asked to open, the magnetic field in the starter collapses, boosting the voltage at the contacts, keeping the current flowing for an instant even tho the contacts are open: an arc occurs.  Most of the time, the contacts continue to open, extinguishing the arc.  But if the contacts are already damaged from arcing, the arc gets a head start because the contacts are already hot...

In TJ's case above, the cause was not welded contacts in the starter solenoid, but rather a stuck starter button.  But in my experience, this is much rarer than welded contacts in the starter solenoid.  Regardless of the cause however, the remedy to a runaway starter is the same:  Disconnect the battery.

Easier said than done.

All cars, and almost all boats have a hard-wired connection between the battery and the starter.  In boats, the usual case is that that "Off-1-Both-2" battery switch is only carrying the house loads - the starter is hard-wired.

I believe that this is a pretty serious safety hazard.

Blue Seas M-Series Mini Selector Battery Switch
Those big battery switches can easily carry the starter current load.  Even the smallest ones have tremendous current carrying capabilities. Here's a mini Blue Seas one:
  • Cranking Rating: 10 sec. 1,500 Amps
  • Intermittent Rating: 5 min. 500 Amps
  • Continuous Rating: 300 Amps
For comparison, cranking Eolian's starter (Perkins 4-236 diesel) draws 200 amps - I know this because everything on Eolian goes thru the shunt for our Link2000 monitor. And everything also goes thru the battery switch on the power panel. Including the starter.  I can't take credit for this - Downeast (Eolian's manufacturer) built her this way.

If the starter on your boat does not go thru a battery switch (or THE battery switch), I'd sure try to find a way to make it so...


Monday, May 7, 2018

Expansion & Bubbles

Everything gets bigger when you heat it.  Fact of the universe.
Water is one of "everything", so when your engine warms up, the cooling water in it gets bigger - it expands.

In older cars, space was left at the top of the radiator for the water to expand into.  In newer cars, the radiator is filled to the brim, and there is an external expansion tank.  There is always one somewhere in the system - there has to be.

Expansion tank on Eolian's engine
It is no different for boat engines.  But.  No radiator, no expansion space in the radiator.  But there has to be an expansion space somewhere in the system.  Right?

OK, now second thought:  air bubbles.  Where do they collect?  Yup, you got it in one - at the highest point in the system, eventually.  In a car, we're back to that space in the radiator.  It's easy to replace the air bubbles in the system with more coolant if they collect in the expansion tank.  It's a good combination of uses.  And in any modern car, the expansion tank or exit to the external reservoir is at the highest point in the system.

Ah, but in a boat.  In a boat, the "radiator" (there isn't one - it's a heat exchanger instead) is unlikely to be the highest point in the system...  Do you have a water heater that gets its heat from engine cooling water?  I'll bet it is mounted considerably higher than the engine.  How about a Red Dot heater (Eolian has both)?  Same question.  So where do the inevitable air bubbles accumulate?

Well, at the highest point in the system.  Always.  On Eolian, that was the water heater.  So, guess how effective the heater was, given that the hot water coils were filled mostly with air?  Yeah, not so much.

Expansion tank, above the water heater

It's been years now, but I installed an auxiliary expansion tank/reservoir at the inlet for the engine cooling water at the water heater.  And collected a lot of air in it.  The expansion tank on the engine simply got filled completely with water - an ineffective and irrelevant (and now removed) bulge in the system.  I put a 14 lb radiator cap on the engine expansion tank, and moved the original 7 lb cap to the auxiliary expansion tank by the water heater.  That way the cap on the engine would never release, and the one on the auxiliary tank would.

Big change in water heater efficiency!

So where do the air bubbles in your engine cooling system accumulate?

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