Front Row Seat

Marathon, Florida
24 42.40 081 N 05.68 W

Friday night sunset looking West.

Friday night sunset, looking Southeast.

Saturday morning sunrise, looking Southeast.

Friday and Saturday have been mostly cloudless days.  Why then the heavy bank of clouds seen in the above two photos looking Southeast?   The answer is that it is a nearly perpetual bank of clouds directly over the Gulf Stream.  That's how close we are here in Marathon.  

I'm a power engineer by background.  Therefore, I love it having a front row center street watching the biggest power engine in the world.   What I'm talking about is the Gulf Stream.  

The Gulf Stream moves 30 million cubic feet (850 thousand cubic meters)  of water per second past me here in Boot Key Harbor.  Off the coast of Newfoundland, the flow is five times larger. Compare that with 0.6 million cusec as the total flow of all rivers emptying into the Atlantic Ocean.     

The water is also warm, so energy in the form of heat is also transported.  Energy transport per unit of time is defined as power.  The Gulf Stream carries lots of power.  Lots and lots.  The total power in the Gulf Stream is 1.4 petawatts.  That's the equivalent of the power generating capacity of 1.4 million of the largest nuclear power plants.  It is 100 times more than the total power demand of men on the whole planet.  Wow that's a lot of power.

That much power is enough to give renewable energy enthusiasts wet dreams.  However, the power is not so easy to exploit for our own purposes.   The water in the Gulf Stream is only a few degrees warmer than the ambient water or air temperatures.  Therefore the Carnot efficiency of a heat engine using that temperature difference would be so low, that such a heat engine would be impractical to make.  (For the benefit of those who never had a course in thermodynamics or who slept through their course, the Carnot efficiency is the maximum theoretical efficiency.  Any real life engine is necessarily worse than a Carnot engine.)

There could be another problem.  If we extracted a large fraction of the Gulf Stream's power, or if we disrupted the flow it would cause global climate changes so big as to make the current greenhouse gas caused changes seem like child's play.  Actually the Gulf Stream is only part of a global circulation pattern of ocean currents that transport heat and salt through all the world's oceans.  Especially in the Northern Hemisphere, all the coastal climates in all countries are heavily dependent on those currents.  

Anyhow, if we did have a practical way of extracting even 1% of that power, we could replace all other energy sources.   If we could do it, we would, but we don't, therefore we can't.  (Ugh what an ugly sentence, but it speaks precisely to my point.)

But for me, as a power engineer, it is a wonderful privilege to be able to sit here and see the visible evidence of nature's colossal power plant at work.  The word awesome is much overused in today's world, but it applies here.

Florida is Big

Marathon, Florida
24 42.40 081 N 05.68 W

Florida is a very big state.  So big, that there seems to be ast least three climate zones.  Look at the three weather forecasts below.  Marathon/Vero/Fernandina   south/mid/north.

Nighttime temperatures here in the keys are significantly warmer than in Vero.  Up in Fernandina, both  day and night temperatures are lower.  Indeed, it even freezes up there.  We heard that in December 2010, the fountain in Saint Augstine froze.  Brrrrrrrrrrrrr.

It reminds me a big of living in Sweden.  There, the weather reports have to give sunrise/sunset times in three north-south zones.   Kiruna, the northernmost big city is above the arctic circle, so for portions of the year, their sunrise/sunset times are listed on the weather report as ---

I learned to sail in Sweden.  In the summer it was great.  I could work a full 8 hour day, then go out and sail for 10 hours, and still be home before dark.  In June, Libby and I could sit on our balcony with a drink.  We could see the sun go down and back up again before we could finish the drink.

The Vergennes Story

Marathon, Florida
24 42.40 081 N 05.68 W

I never told the complete story about Vergennes and Hurricane Irene from last summer.

Just to review; the free docks on Otter Creek in Vergennes is one of our favorite places to visit in summer.  Everything about it is nice.  The ride up Otter Creek.  The picturesque setting, and the charms of Vermont's smallest city.  It is also well sheltered with towering hills surrounding in all directions.  I think I remarked before that a hurricane could pass overhead and we would hardly notice it in there.

However, in face of the approaching storm, we decided instead to ride it out at anchor in Porter Bay nearby.  That worked fine.  There was only one other boat within 1/2 mile of us in Porter Bay.  We were perhaps the safest people in the whole state.   Other boats chose to seek shelter in the "hurricane hole" in Vergennes.  Big mistake.

Why was that a mistake?  Because Otter Creek extends another 100 miles or so upstream of Vergennes.  It drains an enormous basin of mountainous territory.   Thus, soon after the storm passed, the flood waters reached Vergennes.

We visited there, 10 days after the storm, and took the pictures below.  That was just a day or so before Tropical Storm Lee dumped more rain and the creeks swelled once again.  I think the trawler was stuck there for three weeks.

We  talked to the boaters there and this is what they told us.

All the places at the docks were taken by boats seeking shelter.  Several had to be turned away as nobody was willing to raft.  One such boat was the Lois McClure, an 88 foot replica of an 1862 canal schooner.   The boats were tied up to the floating docks provided by the city.  These docks and their fittings are home made by locals who are not experienced in salt water environments.   In one place they are attached to vertical pipes bolted onto a steel wall.  In other places they are tied to posts driven into the mud.  Attachments to the pipes or posts is done by chains, secured by padlocks.

The first problem was that the floating range of these docks was designed to be only 4 feet.  The creek rose more than 10 feet at the crest.   Therefore, the docks and boats attached to them threatened to be pulled under water, if they didn't break loose. However, a heroic city worker came three times in the next few days and at great risk to himself, he loosened the chains to prevent a disaster.

The next problem was that the creek widened until the people on the boats were separated from dry land by 50-60 feet.  At first they used planks as bridges.  When that became overwhelmed, a nearby homeowner lent his row boat and they started a ferry service.  The fastened a line to the base of the flag pole, and the other end to the large trawler in the picture below.  Then they could ferry people back and forth in the row boat while holding on to that line.

It took a long time to drain all that water from the mountains.  On the day we visited, 10 days after Irene, the boats had just started leaving.   That was the first day currents had slacked enough that they felt safe.  


We heard stories from Catskill Creek and Rondout Creek on the Hudson River after Irene.  In those cases entire marinas with boats still attached to the floating docks were ripped loose from the shore and floated down stream.



So, bottom line: Creeks and rivers that drain mountainous watersheds are the last place you should go to seek shelter from a major rain storm.  The post-storm floods can be much worse than the storm.

Tarwathie was docked at this exact spot several weeks ahead.

This Krogen 49 trawler is from Vero Beach.  We recognized it.

The Lois McClure departs with the aid of a tug boat (not visible).
It was touchy, she almost ran into the river bank.

Temperature

Marathon, Florida

24 42.40 081 N 05.68 W

A strong cold front came through here last night.  It didn't bring any rain, but it did bring lots of wind and cold.  Cold is relative; and that's my subject today.

Last night in other parts of Florida the temperature dropped to the 20s.  Here in Marathon the low temperature was only 60.  Nevertheless, the cold is the major topic of discussion on the Cruisers Net this morning.  Nobody is leaving the harbor, and many people are planning to stay on board all day rather then venture out in their dinghies.   Libby and I aren't much different; although Libby was brave enough to go out for groceries first thing.

I remember when we used to sneer at Floridians who complained incessantly about cold temperatures. Well, we are now like them.  Some people would say we're spoiled.  Others say our blood has thinned.  I won't argue. Another word for the same thing is adaptation.

It is pretty amazing how fast we adapted to balmy temperatures since we started cruising.  Our migration habits keep us in the balmy zone.  Basically, 25 degrees north latitude in winter and 45 degrees north latitude in summer.   In spring and fall as we migrate, we tend to follow the balmy temperature band without specifically trying to do so.  

In the past, we've been well adapted to cold.  Both of us grew up in upstate New York where there's plenty of cold and snow to go around.  I remember playing hockey on the river in -45F (-42C) weather.  I felt fine.  However, we never did adapt to excessive heat.  Most of our lives we've lived in places where we did not have air conditioning, nor was it needed.

I wonder if our preferences for moderate temperature played a role in choosing the cruising life.  Down here in Tarwathie's cabin, the water line is up to our hips.  That moderates extremes naturally because water temperature does not go up and down as much as air temperature.  Never once in 7 years have we had a night on Tarwathie when it was too uncomfortably hot to sleep.  On nights when it's cold, we simply add another blanket; that's much simpler.  We do have a cabin heater, but we've never run it through a night.

We've been talking lately about how nice the Rio Dulce in Guatemala sounds.  It would be very nice to spend a summer there.  Before doing that, we would have to find a way to get air conditioning.

Our Next Big Project

Marathon, Florida
24 42.40 081 N 05.68 W


Regular readers know of our persistent problem with vibrations.   We've had the problem since buying the boat nearly 7 years ago.  We had it when the surveyor inspected the boat.  We had it both before and after installing a new engine.   We thought it was normal and something to live with until it chewed up two sets of motor mounts.  We posted the question to this blog and got back a dizzying array of helpful comments.   Here is a list of things we tried or considered.

1. We realigned the engine with the propeller shaft (5 times!)
2. We replaced the motor mounts (2 times)
3. We sent the propeller shaft to a machine stop to check straightness.
4. We installed a new flexible shaft coupler.
5. We put in a new cutlass bearing.
6. We removed, aligned and re-bedded the shaft log. (We don't have a shaft tube, but rather a bronze shaft log.)
7. We hired diesel mechanics (4 times)
8. We considered the thrust bearing.
9. We considered changing to a stiffer or less stiff transmission damper plate.
10. We considered insufficient clearance between the propeller blades and the hull.
11. We considered the propeller pitch. (Too much pitch runs the engine at too low RPM.  It would be like driving a car up hill in 5th gear.  The engine lugs in too high a gear.)
12. We considered getting bigger tougher motor mounts.
13. We considered modifying the engine pan that the motor mounts bolt to to make it stiffer and more stiffly bonded to the hull.  That would be a fiberglass modification.

None of the above changed anything and none of the things only considered seemed likely to lead to a cure according to my expert advisers.


Missing from the above list is having the propeller balanced.  We have a Maxprop.  It is a so-called feathering prop.  The blades reverse the engine is in reverse and the blades feather when we sail without power.  The prop has many moving parts.   We sent it to a prop shop as a box full of loose parts, but there wasn't much they could do with that.  


We asked the Beta engine manufacturer for advice.  He had us run a test with the engine and shaft decoupled.   The result was no vibrations.  The test seemed ridiculous to me because we reported that there were no vibrations with the engine in neutral.  Their conclusion: nothing wrong with their scope of supply; align it yet again.


All that had me pulling out my hair.  I visualized a future spending thousands of dollars every year trying and retrying various solutions and testing numerous theories; with no results.


Finally, almost by accident, I stumbled across one diagnostic test never tried before.  I ran it full speed in reverse.  WOW, no vibrations!   Nobody thought before to try that.  What difference should it make in forward or reverse?   Besides.  backing up a sailboat with tiller steering at 6 knots is difficult and dangerous.  It is like backing up in your car at 40 mph. In normal circumstances, one would never attempt it.  None of the four mechanics, nor Beta, nor our Westsail expert Bud Taplin, thought to run a test in reverse.


Note that all of the possible causes listed above would produce the same vibrations in forward or reverse.  This simple diagnostic test eliminated all of them.


With that additional bit of diagnostic information, it took only a few minutes and one phone call to home in on what I think is the real explanation.   Some of the internal gear teeth in the Maxprop propeller are worn out.  99% of the time when the engine is in forward, all the load wears on the same teeth.  Different teeth are engaged when in reverse or when feathered.  Of course there is no significant load anyhow in reverse or feathered. So only the forward teeth wore.  Worn teeth allow play in the blade position and they shake.


Now we've ordered a new fixed propeller. It has no moving parts.  It is just a solid block of passive bronze.  As soon as it comes, we'll go up on the hard and install it.  No more complicated feathering prop for us.  I've decided that owning and maintaining such a device is above my pay grade.  Let the KISS principle rein.  


Wish us luck.