WPSU

Monday, June 7, 2010

A Tale of Two Batteries



It’s Monday, June 7, and we have been docked in Owsego, NY, since Saturday afternoon. How we got here on Saturday is a tale of two batteries.

(WARNING: This is a long post, with lots of technicalities. If you are a boat person, or an engineering person, or Cap’n Bill and you see that I got something wrong here, please let me know!)

We left Fulton, NY, on Saturday under lightly cloudy but bright skies with a light wind. Our solar system had still not fully recharged, so we were running on diesel.


The fun began at Lock 6 on the Oswego Canal. Lock are described in terms of their “lift,” or how high the waters will lift a boat going upstream, and this lock is very deep, with a lift of 18 feet.

We were going down, not up. It was awe-inspiring down at the bottom of the lock—we were BELOW the level of the lock gates, which are enormous in their own right. (See photo above.) It was also was extremely windy at the bottom of the lock. We were having a hard time holding the boat to the wall, so, as soon as Bill saw the lock doors start to open, he cast off.

But—just like Thursday on Onandaga Lake--the diesel did not start. And still not enough juice to run on electric.



(Don Heller asked: “Whatever happened on Thursday, when the diesel failed on Onandaga Lake?” We tried the diesel again later in the day and the engine started right up. That suggested to Bill that the cranking battery (original to the boat and not part of our half-ton array of batteries to store solar power) was starting to fail.

Anyway, back to the bottom of the lock, where our 14 tons of steel was floating fast toward the opposite lock wall, also made of steel. We hollered for the locktender, who threw us a line and singlehandedly hauled our boat out of the lock. (Holy cow, Batman! Was that locktender superhuman? Well, no, Robin—but he was strong--and a very good sport, since this WAS quite a grunt. But you CAN drag this boat around, VERY SLOOOOWLY)

The locktender maneuvered the line across the little footbridge that crosses each lock, and helped us secure to the opposite wall, outside of the lock, away from boat traffic.

Somewhere in all this excitement, we heard an unfamiliar noise: the bilge pump. Bill went below (the engine room is below the stern deck; you get access to this space by removing a large square of deck flooring made of VERY heavy marine plywood, which the deckhand always obnoxiously reminds the captain to stow on the far side of the boat, so it won’t fall on the captain’s head just as he is exiting the engine room and knock him senseless into the bilge below) and discovered we were taking on water.

(Who would have thought that, so soon into our voyage, we would get to test this principle we learned from reading books about the good old days on the Erie Canal: “Canal boats take a long time to sink”?)

A bit more exploration revealed the cause of water in the bilges: Our propeller shaft had come loose.

In this kind of a boat, the propeller shaft (photo above) runs from the engine, through a hole in the hull of the boat (below the waterline), to the exterior—where, of course, the propeller shaft powers the propeller.

Naturally it's a bad thing to have a hole in your hull below the waterline. So, at the interface between boat hull and propeller shaft is something called the “stuffing box,” which keeps water out (well, mostly; the stuffing box is designed to let a little water in order to cool the propeller shaft, which generates heat through friction as it turns.) In really really old boats the stuffing box was just that—a box stuffed with oily rags and other junk to keep the water out.

During the boat re-fit, before we left, Bill had pulled the propeller shaft out of the boat in order to install the new electric motor. He says he recalled leaving off a tiny piece of wire, kind of like a cotter pin, when he put the shaft back in place, because, he believed it wasn’t necessary-- if the prop shaft were to come loose, he thought the enormous gear he had just installed would do the job of preventing the shaft from backing completely out of the boat. Which it did!

But apparently that little wire was needed to prevent the problem we were having—the prop shaft loosening up and backing a few inches out of the boat, letting water in.

Anyway, the prop shaft clearly needed to return to its rightful place before we could proceed, and it’s not like we were anywhere near a boat lift capable of lifting our 13 tons up out of the water for repairs. It was time for the captain to take another swim.

Luckily we have an enormous mallet on board and, working underwater (with the crew hovering anxiously on deck, life ring and radio in hand), Bill was able to put the propellor shaft back in place. And our repair stop took long enough that we built up enough charge in our solar array to power the boat.

We proceeded through three more locks over the course of Saturday afternoon, and, well, locktenders talk to one another on the radio. So news of Bill’s repair work proceeded us. We are simultaneously lubbers for screwing up in locks and heroic figures for the way the cap'n can fix up his boat singlehandedly.

As for that cranking battery; well, this IS a tale of TWO batteries. Besides the cranking battery, the boat came with what you call the “house” battery, which can power things like the fridge and the lights IF the boat is not plugged into “shore power,” i.e. an electrical outlet at a marina.

(What about that half-ton of batteries stashed under the seat in the workroom?you ask. Well, Bill is continuing the refit as we go, and within a week or two all our battery systems will be interconnected and we’ll be able to operate everything on solar-generated power--providing we get enuf sunshine).

But the big question right now is, why would the cranking battery be failing? Bear with me.

For navigation purposes on our trip, we purchased a “chart plotter,” which is a marine version of a GPS—it's a Garmin Nuvvi for your boat. With a chart plotter, you can purchase and load marine charts that show you how deep the water is, where the navigational buoys are, and where the dangerous rocks are, useful stuff like that—features lacking on an ordinary GPS).

Our chart plotter is made to be hard-wired into the boat’s electrical system, but on OUR boat, doing that would mean permanently mounting an expensive device outside on the stern deck. It would also mean using the plotter only ouside, in a place that is open to the wind and the rain. We thought it might be nice to be able to take the plotter inside, out of the weather, for route planning on bad-weather days.

So Bill spliced some wires and rigged the thing so it can plug into a 12-V outlet on the stern pedestal (the pedestal is the device that supports the throttle and other controls). You know how a portable GPS system can plug into your car’s cigarette lighter? It’s the same kind of outlet and plug.

Bill believed that, with this set-up, the chart plotter was drawing power from the “house” battery—which is bigger than the cranking battery (both get recharged when we are underway, just like your car battery gets re-charged when you drive.

Anyway, Bill now concludes that the chart plotter must have been drawing from the cranking battery. And the chart plotter draws a LOT of power—enough that, when we were running on solar-electric AND using the chart plotter, we must have drawn the cranking battery dangerously low, possibly damaging it.

So today, under the sunshine at our safe harbor between Locks 7 and 8 (just below Oswego Harbor), our solar panels are working away, stashing juice in our half-ton battery bank; a new battery is on order from the local auto parts store; and Bill is re-checking the propshaft fittings. Meanwhile we are carefully watching the weather forecast to see when conditions will be favorable to venture out onto big water: Lake Ontario.

12 comments:

  1. Wow -- never a dull moment on the Dragonfly! Actually, this was a very interesting explanation of what was going on. Keep up the great detail!

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  2. Check out this lock I was on in Portugal -- don't remember the exact height, but much taller than 18 feet!
    http://www.facebook.com/photo.php?pid=31170217&l=fd45afea8b&id=1507988370

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  3. Oh, and how do I post comments on Dad's sunboat blog? I can't seem to figure it out.

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  4. All I can say is WOW! You are going to have some wonderful tales to tell your grandchildren one day. Keep the great stories and pictures coming. I had a good laugh. Have a sunshiney day!!! Love you both. Aunt Mary

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  5. To blog followers: Glad to get your questions, I'll do my best to answer, and THANKS for your forebearance if I don't answer right away. "How we get internet access" is a story almost as complicated as my tale of two batteries!

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  6. To blog followers: Glad to get your questions, I'll do my best to answer, and THANKS for your forebearance if I don't answer right away. "How we get internet access" is a story almost as complicated as my tale of two batteries!

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  7. You know there's a super hero story in there somewhere. The captain swims underwater armed with a heavy mallet! Seems like at the end of this trip you two should be given doctorates in marine, electrical, solar and diesel engineering!

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  8. Wow, what a story. When you first mentioned the propeller issue I was hoping an underwater repair would be in order. Very theatrical.

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  9. Newsboy said, Bill was earning a doctorate in electrical engineering on this trip. . .The funny thing is, when Bill was getting his Ph.D (in Education) he was very interested in using computers in the classroom in innovative ways. He wanted to minor in computer science, but in the mid-80s at Stanford, EVERYBODY wanted to minor in computer science, so the university stacked the deck to put extreme limits on how many people could do that. But by diligent study of the course catalog Bill learned he could minor in (wait for it) ELECTRICAL ENGINEERING and take the specific computer science courses he wanted.

    Of course throughout the re-fit of the Dragonfly we have had many many occasions to say, "Bill! Thank goodness you minored in electrical engineering!"

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  10. Newsboy said, Bill was earning a doctorate in electrical engineering on this trip. . .The funny thing is, when Bill was getting his Ph.D (in Education) he was very interested in using computers in the classroom in innovative ways. He wanted to minor in computer science, but in the mid-80s at Stanford, EVERYBODY wanted to minor in computer science, so the university stacked the deck to put extreme limits on how many people could do that. But by diligent study of the course catalog Bill learned he could minor in (wait for it) ELECTRICAL ENGINEERING and take the specific computer science courses he wanted.

    Of course throughout the re-fit of the Dragonfly we have had many many occasions to say, "Bill! Thank goodness you minored in electrical engineering!"

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  11. Sounds like a whole lot of fun -- but then I have a strange sense of fun.

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