Monday, May 30, 2011

Fossil Hunting in Fairhaven

rev. 5-30-2011

The Chesapeake Bay is famous for it's large, complete, and exposed Miocene Formation deposits, best know at the Calvert Cliffs, but extending from Fairhaven to St. Mary's. Since my daughter was small, we would walk these beaches, picking up shark teeth and molluscs and talking about what the Bay might have been like then. When she was very small, it was simple, fun talk of a time when the Bay was ocean, after dinosaurs but before people. Even a small child can see that shells belong to organism that are gone, and with a little explanation, to organisms that can't and don't live in brackish water.

Shark Toothed Dolphin  (Squalodontidae)

Some of our favorite places are the cliffs and beaches near Fairhaven. While the beaches are not littered with the large scallop shells that characterize Calvert Cliffs beaches, there are many small sharks teeth and other small shells, and occasionally something more interesting. Once, to our delight, a small section of vertebrae had been exposed by the passage of a tropical storm.

Thorasic Vertibrae

They were all broken up and scattered, and it took some time to assembly and identify the remains, not being a paleontologist and having only a rudimentary knowledge of mammal skeletons. A trip to the Smithsonian in Washington made it clear that it was a marine mammal, and trip to the Smithsonian Naturalists Center made it clear that it was a dolphin or small whale. Some reading about the formation and the discovery of a small whale skull by others, a short time later only a few feet away, makes it likely that this is from a small whale about 14 million years old.

Arrowheads are always tricky to date, even more so when found loose on the surface. Since there are no context or excavation clues, the best that can be done is compare this artifact to others that are better dated. This could be anywhere between one thousand and several thousand years old; I'm guessing Bakers Creek style, about 2,400 BCE since we have found others of that type in the area, but it's worn and could be older, perhaps 5,000-7,000 BCE.

Other times, it was evidence of our human past--and perhaps evidence that Fairhaven has been a nice spot for a long time. All I know is that my daughter could spot an arrowhead in a mall parking lot given time to look; she has found several on the beach.

Pretty neat.

Note: Since nearly all of the cliffs and beaches adjoin private property, stay on the beach and be a quiet visitor. Please do not dig anywhere as erosion is a serious problem. Additionally, that many of these cliffs are not too stable, and that after heavy rains collapses and land slides are common. There have been fatalities and some cliff beaches are closed for this reason (the cliffs grow progressively less stable, heading south). Do not climb on the cliffs.

Sunday, May 22, 2011

Don and Steve Round the Horn.

 Cobb Island Lifesaving Station. Cobb Island, VA.  
Although this trip deserves and will receive better description, Don delivered the above documentary evidence of sailing around the Delmarva, nearly halfway by now. This photo doesn't really do the scenery justice, an old lifesaving station beat down by storms. Neither does it do justice to the feeling of elation at entering the harbor after passing one of the longer stretches of uninhabited and shelterless coast. The entrance itself is potentially tricky, moving with the passage of storms and not always marked correctly. The Coast Pilot suggest local knowledge, so it's a definite milestone. I imagine the sailboats that have visited this harbor--in the past few decades at least--could be counted on your fingers. Adventuresome stuff.

Steve and Don have sailed their Starwind 223 from mid-Bay, around Cape Charles, some 175 miles to get this far, and will probably cover close to 500 miles by the time they return. I expect some tall tales and fine photos.

The station about 80 years ago.
What a great way to start the season. They probably even got a jump on the flies!

Sunday, May 15, 2011

A Minnow Trap from Recycled Flotsom

My back has flared up in annual protest for some perceived slight. I can't sail, I can't ride, I can barely walk. I can post something trivial.

Collecting critters and fishing may not be sailing, but I love them both. Even more, I love introducing my daughter to the natural world. Add to that father -daughter time the opportunity to teach a D-I-Y ethic, recycling and thrift all in one stroke; a bargain.

Any plastic bottle with a cap will do. Two are required. Any beat-up thing from the wrack line will do. 2-liter jugs are best, but even 12-ounce bottles do well.
  • Cut the bottom off one.
  • Cut the top off the other and insert it inverted. Leave the cap on the external neck only--it's handy for decanting the catch. The other neck, of course, is the entrance.
  • Secure them together. I've seen everything from staples to cable ties to bolts to bits of string.
  • Poke a few 1/8 holes near the neck to allow some water flow, carrying the scent of the bait our the inverted opening. Additional holes only attract fish away from the trap entrance.
  • Tie a string around the neck to orient the neck into the flow, if any.
  • Add bait. Bread is a good starting point.
We've caught minnows, spring peepers, small crabs, grass shrimp, and eels.

Something to entertain the kids and an idea to keep in your tool box for your next Cast-Away adventure.

 Post Script. We actually carry a commercial minnow trap, which gets heavy use, both at the dock and at anchor (use care at anchor not to wrap the line around the rudders--just enough line to get it to the bottom).

Friday, May 6, 2011

Aero Bars. Yeah, I'm off Sailing Topics...

Well, only for a while.

When I got back into riding I had carpal tunnel and the vibration was a killer. Aero bars were a life saver, worth sharing. I started with these:

When I got my new toy, I moved on to these:

The hinged model failed at the hinge from metal fatigue after only a few years of moderate use, which I reasoned was too little time.

Because I need a neutral wrist position I need a bar with an up-turned end. Would bar end shifters be better? No, I think I prefer brake lever shifters, since most shifting occurs on hilly terrain. The bars do add about a pound to the bike, but I don't live in the mountains, not any more.  

I think there is little question that aero bars are faster and more comfortable on the flats, racer or not. There is a learning curve: expect them to feel twitchy to start, but this soon passes; be careful on bumps; no, you can't reach the brakes, but you soon learn to switch one or two hands smoothly; set them high and wide when starting and stay far from traffic; if you're touring and value ease and comfort over speed, set them higher, further apart and not so far forward, and them leave them there. A little cork tape near the ends is nice too.

I'll repeat, they're not such a good idea in traffic. Moderation in all things.

Wednesday, May 4, 2011

A New Toy

I dreamed of something like this in college, when racing was a passion. Then I destroyed my knee in a crash and spent 30 years waiting to ride again. What a difference aluminum and carbon fiber make.
 Now I am old, crippled, and unworthy. Perhaps I'll look fast enough if I simply lean it against a bench, pretending I've come far; like Mark Twain, I suppose I have and should be glad to look the part. Perhaps I should paint it olive drab and scratch it up a bit.

I do promise that this will NOT be riding on Shoal Survivor's bike rack, dripping in salt. It's older sibling has inherited that chore.

PS. My wife tells me I have 2 mistresses now, both starting with "B": bike and boat. She's right. The past few nights have been consumed with tweeking and minor additions, just like the boat.

Solar Panels

Rev. April 20, 2014

Cruising farther means more nights on the road. Limited battery capacity flat means more nights in marinas. That's money, but more importantly, it means bending our plans to fit in marina stays, and I don't like that. We could go sans power, but when the mid-summer Chesapeake humidity hits and the wind fades, fans equal sleep.
The Choices
We could run a Honda generator or use a wind generator. Too much noise. I like passive and silent, so panels it is. We have a substantial deck, but we use all of it, either lounging or sailing. Only 2 small areas on our hard top remain low-traffic, no more than 15 square feet.

We have 270 amp-hours (AH) in nameplate storage  capacity from 3 x group 27 batteries, but realistically we can only use 140 AH without straining the batteries and shortening their life. We know from experience that we run about a 40-70 AH deficit each day, depending on use of lights, DVD, fans, and CPAP.

The available 15 feet square will fit 2 x 100-watt panels, or about 60 AH in real-world charging capability, if we consider shading and passing clouds. While this won't replace out entire deficit when we're energy hungry, it will stretch our battery life and may be enough if power is used responsibly and charging is supplemented with some coincidental engine time. For better or worse, this is our chosen compromise.

The Panels
Price matters. We also needed a specific shape. I hunted for something cheaper with good customer ratings and came up with these:
Renology 100W

They are of a simple design that appears to be well executed. I load tested them in the front yard, in the sun, and they were on the numbers. Nice wiring boxes; however, accessing an additional knockout required some very careful drilling (we padded and protected the back side of the cells with thin plywood over cloth), since smacking it firmly with a screw driver seemed unwise. Once inside, there are plenty of extra terminals.

(Note: to "yard test" the panels you will need a load close to the projected out put of the cells. Other wise, you will be so far from the maximum power point you will see a much lower value.Of course, without an MPPT controller in the circuit, this means running a bulb at 18 volts, so keep it brief!)

The Mounting
The adjustable feet used to compensate for the crown in the hard top may be handy any place a self-leveling or adjustable mounting is needed, just as threaded studs are used to mount and level engines, traffic signs, industrial equipment, and outdoor lighting poles; perhaps the only innovative part of this installation. they neatly address the recurring challenge every D-I-Y sailor faces who lives and hour from his boat but likes to tackle significant projects; how do I prefabricate as much as practical and insure it will fit easily and properly when I reach the dock? This was a true piece of cake.

The hard top is not flat; in fact, it domes asymmetrically about 3/4-inch over 3 feet. Additionally, we need to protect the panels from accidentally dropping of the boom and provide air flow under the panels (PV cells lose efficiency when hot--more on that later). I also dislike the idea of drilling holes in a foam core deck. The solution? A simple aluminum frame and 4 adjustable feet for leveling and load distribution.

The feet are 1 1/2" x 1 1/2" x 1/2" prelaminated FRP with 1/4" x 1 1/2" stainless threaded rods tapped and epoxied in place. This material holds threads very well, and even without the epoxy, any thickness over 3/8" will break the bolt or strip the nut before stripping the FRP threads (I tested a few trial pieces to destruction).

Note: remember to degrease bolts and rods before embedding in epoxy. Residual thread cutting lubricant will interfere with the bond. A little sanding is good too. In this case, however, because the nuts tighten against each other, there is little torque on the rod.

Installed with nuts and washers above and below the aluminum frame, these provide a solid mount that easily accommodates the curve of the deck. In my case I embedded the cut end of the rod in the FRP block, but in some cases it may be desirable to leave the studs very long and then trim after test-fitting. To insure that the threads are not spoiled when the rod is cut, be certain to thread the nuts on first. After cutting the rod, camfer the cut end and then remove the nut to straighten the threads.

These are another excellent choice, though less "trick" looking. I have used these for interior equipment mounting, including bolting down an air conditioning unit. From Duckworks.

The frame is nothing more than two  2" x 2" x 1/8" aluminum rails bolted to pre-drilled holes in the underside of the panel frame. These rails are as stiff as a pine 2 x 6 and are high enough to keep the boom off the glass. The slightly elevated mount allows free air circulation under the panels for cooling and drying. To insure good alignment...

Note 4-20-2014: The boom has contacted this frame numerous times, occasionally with considerable force (me winching, not realizing the boom is resting on the frame) with no damage. I think the design is about right and would not go any lighter in this location.
  • Drill the holes in the frame only slightly oversize (+ 1/32-inch) to insure good bolt alignment. Wobble the drill slightly to create an allowance for misalignment.
  • Dry-run the installation, adjusting the legs to the correct height.
  • Tape off the outline of each foot to minimize the epoxy mess. Sand the gelcoat surface.
  • Bond with thickened epoxy (West System with fumed silica/Cabosil). Tighten the nuts slightly to insure the feet are aligned vertically with the frame. Remove tape before the epoxy cures.
  • Be warned, the whole assembly will try to slowly slide off the deck. Temporary props and duct tape may be useful.
  • Remove the masking tape before the epoxy is set. It become very difficult later.
  • After final cure. remove the equipment and frame and re-drill the mounting holes about 1/32-inch larger to insure easy removal in the future. If there is significant crown on the deck, there may be some binding during this removal step because the studs will not be parallel to each other.
  • Reinstall and tighten the nuts.
Although this sounds convoluted, it is simple and fast and insures that the panels can be removed in minutes for for final wiring or any future trouble shooting. All parts are easily prefabricated at home, always a plus in convenience, time, and workmanship.

Pre-bonding adjustments were made.
The Charger
A 15 amp charger with an LCD screen is mounted in the starboard hull equipment bay, behind the steering gear and galvanic isolator. Short wire runs, out of the weather, and easily accessible. PDQ did a nice job with the access panels.
Morning Star 15 Amp charger

What about MPPT (Maximum Power Point Tracking) chargers? Photovoltaic cells (PV) don't simply crank out 12 volts of electricity and magically charge batteries; they put out something between 23V and 0V at variable current. The maximum power point, where V x I = W is at a maximum, is generally at about 16.4V. An MPPT controller senses this and keeps the panel output in the sweet spot while providing the battery the voltage it requires for proper charging. That is assuming cool temperatures and a blue sky.

For a little more on MPPT charging, Wikipedia is always a quick source: Wiki on MPPT chargers

If there are clouds or haze, or if the panel is heated above it's rated temperature, the maximum power point will shift left, to lower voltage. On the Chesapeake in mid-summer heat can easily shift the MPP from 16.5V to 15V. What is the actual required charging voltage? That varies with the state of charge; when near full charge 14.5V is a very good match, but when first charging a 50% discharged battery we may need only 12.2V and some efficiency will be lost, perhaps 16%. MPPT is at it's best when first charging deeply discharged batteries.

What does a power curve look like? The below table and graph are for a 1.1 watt panel, but you can easily scale it to fit your application. All 36 cell panels will have very similar voltages and power curves, regardless of wattage. This graph assumes 75F ambient temperature, a high sun and a right angle orientation, and NO shading or cloud cover.

How much does heat lower efficiency? the output voltage is lowered by about 0.041V/F, or about 1V lower on a scorching day than on the cool spring day when you did your installation (assuming you allowed good ventilation to the underside--it could be worse). In other words when it hits 95F, the MPP voltage will be about 16.4 - 1V = 15.4V. Since out electric load is maximum on a hazy 95F day, this is the most relevant MPP. (Some will argue that cool weather charging is more critical, since the days are shorter, nights longer--more lights--and the sun lower, but it is running the fans in the summer heat that always does us in. Plan according to your reality.)

Shading due to haze lowers the output amperage but does not significantly lower the MPP until severe (evening or heavy clouds). Spot shading (a sail or even a shroud) can be devastating, depending on whether it takes a portion of a column (small amperage drop) or a row (small voltage drop that effectively shuts the panel down). However, the reason we did not put a panel under the boom was not shading (if we want zero shading we take the boom far to the side); it was because we walk there when furling the sail and wanted to leave one free impact zone where we wouldn't worry over sailcovers and ropes and even loungers.

For some detail on panel output corrections: PV cell output

Series vs. Parallel Wiring
This has been debated to death on the web. When panels are wired in series an MPPT controller can deliver slightly more power during periods of low light; simply put, the voltage can stay at usable levels longer and resistance losses can be a bit less. However, if any shading occurs, the drop in output is much larger than it is in parallel installations, where only the blocked cell is depowered, not the train. For boats where some shading is likely, parallel wiring is more practical. For a terrestrial roof top installation, series wiring and higher voltages can be explored.

And I didn't even analyze the shading loss owed to seagull poop. It turns out we can't really see much difference when we clean the panels; I guess we're disgusted long before it is functionally too bad.

I've probably given up 5-10% in charging capacity on a typical day by using a simple controller. I suspect for most people, larger panels are a better investment at this scale, but it could go either way; for a project over 200 watts, choose an MPPT controller.

Wire Routing
I expected hiding the wires to be a battle, but pulling the wire took less than 30 minutes. Unique to the PDQ 32, but here it is:

  • The panels are connected to each other above the deck by hiding the wire (2 x 12 awg) in wire duct. The stuff is intended for hiding phone cables, is strongly self adhesive, and would probably fit 3 x 12 awg or 2 x 10 awg wires. It snaps open to the side, should you need to service the cable.
  • From the panel to the deck above the helm light is only ~ 2 1/2 inches; wire loom covers this.
  • From the light to an existing hole in the stainless hardtop support is only 2 inches. Again, a bit of wire loom covers this plus the existing wires nicely.
  • The wire runs down inside the support, forward across the aft cabin ceiling above the liner to the steering gear/instrument cluster access, and down to the charger, below the galvanic isolator.
  • From the charger to the main bus bars.
  • In-line 15 amp fuse between the bus and charger.
Total wire run, about 15 feet each side, 10 AWG.

Total Cost
With all materials (of course, the might-need stash coughed-up some bits an pieces, including the wire and FRP), about $700.00. I struggled with the decision, but if it becomes a 20-year investment and saves a few nights a year charging batteries for $1.50/foot + electric + taxes, then I come out ahead in only 2 1/2 years. Not too bad and better than my 401-K in the best of times. Installation only took 8 hours, including making the feet and frame at home, so not too bad. Time spent puzzling it through? We don't count that.

  • The birds love to poop on the boat, but unless the situation is awful, the amperage drop is only a few percent.
  • I've seen panels installed under impressive crash bar protection, but this amounts to permanent shade.
  • I've unplugged from shore power as there doesn't seem much use in running both (if I had a large sump pump I might reconsider this, but I have none). Moreover, both systems have charging algorithms the float and equalize, and they can easily confuse each other. One less thing to disconnect when day sailing, an advantage I had not foreseen. 
  • The panels easily manage any day sailing usage (1-8 amps) before we even return to the dock.
  • While sailing one panel is often shaded, while the other is almost always clear. When anchored, both are easily exposed by swinging the boom off and securing forward.
  • Summer charging has been great, but cloudy fall weather has been troublesome: shorter days, more clouds, and longer nights.
  • Typical output, with no shading: 9 amps at 14 volts on a sunny day, 0.8-2.5 amps in heavy clouds. The most I have seen was 9.6 amps, and by Fall 7.4 amps is good, given the lower sun angle. The reality is that without angling the panels toward the sun you will always see somewhat less than the rated capacity. While sailing everything depends on the course; both panels may be shaded, or neither.

Follow-up, March 25, 2012: Amperage on sunny day still tops out at 8 amps, about the same as day-one when corrected for sun angle.

April 20, 2014: Still charging at the original rate. No sign of water intrusion.

August 11, 2016: Still charging at capacity.

 After 5 years.