Repair to the bowsprit

A couple weeks ago, David and I took Mahdee out for just a little Sunday morning jaunt between rain showers. Funny how a few minutes of inattention can turn into days of repairs later… Yes, somehow a bit of wood had managed to get beneath the shipping bowsprit in such a way that when the spar was lowered into position, the stresses applied managed to split the foot of the bowsprit. Is there a good thing? well, when the spar is in use, it is in compression upon a pin forward of the damaged area so the damaged wood isn’t loaded up at all. Bad thing? it added another repair to our list of “things to fix” and this one required sooner rather than later.

Before going further, let me get into a little discussion of the bowsprit’s purpose. Many people wonder why schooners tend to have bowsprits. So what is its purpose? To bring the effort of the furthest forward sail, the jib, the proper distance forward to get rid of any unbalanced helm–weather helm–caused by the schooner’s large mainsail but not so far forward as to create lee helm. That probably sounds like a bit of gibberish to some of our friends. For our non-boating friends, I’ll explain further: When sailing a boat with an unbalanced helm, it is somewhat like driving a car that needs wheel alignment. You can’t let go the wheel lest the boat quickly spin up or downwind depending upon the balance of the sails. The boat’s underwater hull shape, heel angle, as well as position of the sails in use at any given time can create the unbalanced “weather” or “lee” helm. The wind’s force on all the sails aft of the boat’s fore-and-aft center of gravity (CG, a pivot point and there are more than one CG since we have a fore-and-aft CG as well as a vertical CG and just to confuse things a bit further, sometimes people call the center of effort of the sails the CG as well) tend to point the boat up into the wind, to weather, whereas the wind force in the sails forward of the CG tend to make the boat fall off away from the direction of the wind, to lee. These windward and leeward tendencies are called “weather helm” and “lee helm.” When sailing downwind, we love to have lee helm as it keeps us pointed properly and so we can put lots of headsails up and leave the mainsail down, enjoying the ride. Other points of sail are not so easy for balance for most boats. On the day I videoed my solo watch (see embedded video here), you may note the wheel doesn’t turn at all — it is locked into a single position but we’re gloriously sailing downwind.  This is because I only have up the foresail and staysail, both have center of effort forward of the boat’s CG and creating just enough lee helm that when the waves push us around a bit, the wind in the sails keeps us pointed running downwind.

Since the hull shape makes a boat’s in-water resistance change the exact position of the CG, it isn’t really obvious and visible at all. The CG on an individual boat can vary with the boat’s loading.  Loading can move the boat’s CG fore and aft–a heavy bow with too much anchor chain or heavy stern with too many fuel tanks and batteries for example rather than exactly as the naval architect intended will change the fore-and-aft CG. Even before we load her, Mahdee tends to be a bit stern heavy and has a cutaway forekeel forward and a deep keel aft so her tendencies are a bit…aft…to start — Crocker’s calculations of CG show her CG a few inches forward of the aft-set mainmast — and then we seem to have a bad habit of loading her up with full fuel tanks aft, supplies midships, and while we try very hard to load up the forecastle with extra anchors and whatnot, we must admit we contribute to the weather helm situation if we’re not careful of how we load her pre-voyage. Her ideal load is with mostly empty aft fuel tanks coupled with a lot of spare water cans sitting in the forecastle. Note “forecastle” sometimes spelled fo’c’sle is pronounced “foksol” like… “folk soul” by most people.

When we use the foresail and staysail alone as we do in big winds when we’re trying to be cautious and importantly trying to not tire out our double handed crew, the jib on the bowsprit stays in the nets. But when we raise the mainsail, the jib is a requirement and the bowsprit a very important spar aboard Mahdee. So after the “crack” and “oops” sounded simultaneously, we knew we had to repair the bowsprit asap. I decided I would paint the ‘sprit while it is removed since it has a few rubbed spots and dents in need of care. It was painted in 2009 and the last time it was touched up was in 2012. After the damage, it rained all the following week. Good friends from DC visited the next weekend and we explored local house museums, eateries, and parks with them for three days. Then with Buttercup and Wesley vying for attention and smog checks coming up, time flew by with us elsewhere diagnosing car issues and focused on their needs. Buttercup’s smog check completed and Wesley stuck non-opp and waiting for parts, we were finally ready to do the bowsprit — three busy weeks had flown by and last Sunday evening was the first moment we could have at it with the bowsprit. The sun was setting and knowing the next few days would be very busy and then rainy, David said “now or never.”

Our rig has twin forestays at the stem, so taking the shipping bowsprit off doesn’t impact the rig as it does on many boats but it still was a bit of a jigsaw puzzle to bring the ‘sprit onto the foredeck without taking all the hardware off of it. I was game to remove the hardware, David, not so much. He dislikes doing anything he perceives “unnecessary” and he perceives removal of the hardware as that. Of course, as the person painting, I think of the ease of painting the ‘sprit with no hardware as much better than masking off hardware and dealing with wood-to-bronze interfaces. With time fleeting and the sun lowering, David’s method ruled because it really was a matter of doing it then or waiting for some indeterminate time before we’d both be available to do the removal together.

It took a bit of digging to retrieve the beat up plastic sawhorses from beneath the fenders, lines, oars, paddles, and other stuff we store in Mahdee’s forecastle. The 105 lb CQR was removed and the chain brought inboard — I ran the trusty electric windlass so it took up the load and kept me from having to do any heavy lifting. Then, the bowsprit shrouds called “whisker stays” were removed from the tip, the jibstay released, and netting released from a few spots. We’d lowered the bowsprit over the marina dock so this was all done by David working on the dock with arms stretched high overhead — almost not quite able to reach the fasteners and clips releasing it all but with no step stool or ladder, the only choice.

Then the bowsprit was swung up vertically again to allow us to remove the big bronze pin, a bearing surface, at the aft-most foot of the sprit. Pound, pound, with a hammer and old screwdriver used as a punch, the pin slid out of the bronze sleeve we’d made for it during our bowsprit repairs in 2009. With the jib halyard attached to the front and the staysail topping lift to the aft end of the bowsprit, David skillfully threaded the heavy bowsprit between the twin forestays and onto our wobbly plastic sawhorses while I cringed and kept the aft end from swinging wildly around. Once settled onto the sawhorses, an extra line was wrapped onto a cleat on it and attached to a nearby pin rack on the fore-shrouds to keep the ‘sprit from swinging inwards and smacking the foremast if the sawhorses failed, and we both let out a big “whew” and sigh of relief that we’d not damaged Mahdee while bringing the spar inboard and we still have a half hour of fading light.

It is bit over 17 feet from the stem to the breakdeck and the spar sits along the entire distance. Amazingly long. When shipped into the vertical position or lowered out the front of the boat to hang over the water, I never realize how truly long that spar is. The few times we’ve entered marinas without it shipped inboard, I’ve worried about thwacking a dockbox or another boat, of course!

David had a busy week away from the boat, so on Monday I glued up and clamped the damaged area and was quite pleased with the tight seam. On Wednesday I added a bit more waterproof wood glue–Tightbond III–to a couple small cracks and then ignored the spar during the winds and rains of Thursday, Friday, and Saturday. Now to sand and paint the bowsprit before re-mounting it on its hinge pin and attaching all the fittings to it so it can be used again while sailing.

Masts and Chocolate for the DIY-er

Trader Joe's Chocolate Cube Varnish Container
What do these two have in common?  Very little except those masts need “refreshing” aka repainting or at a minimum a good buff and wax and the chocolates are essential to successful application of paint and varnish.  See the connection? I’ll admit it’s pretty slim.  The masts get touched up with paint, buffed, and waxed next weekend since I completed the varnishing last week.

Now about the chocolate, you see, we tend to buy our chocolate in various forms from Trader Joe’s.  In these seemingly identical clear plastic cubes throughout the year.  If you don’t buy the chocolate, you don’t get the cubes. I keep the cubes because they make a great varnish container.  This one, from last year, reminds me that Trader Joe’s no longer sells the lovely Orange Sticks.  It was our favorite: orange jelly center covered with dark chocolate.  They tell us they’ll have it again someday.  We don’t believe them since it’s been a year now.

Actually, those cubes will give you pretty much a perfect varnish container if you take a couple Popsicle sticks…ummm…let’s digress a little bit more about where the sticks come from:  you get the Popsicle sticks in the summertime when it’s hot and you’ve just got to have a lime-bar.  You save the summertime Popsicle sticks for the fall varnish-fest.  You also save the plastic cubes that your Trader Joe’s chocolate came in for the same varnish-fest.  This really doesn’t take much space–even aboard a boat–just a tiny little spot in my project bin where the cubes can stack and the sticks can stand next to them.

Then, in the fall, you pull these things out because you’re ready for your paint and varnish-fest to protect all the exterior woodwork through a winter of rain or worse inclement weather.  You grab a cube and take a thin plastic baggie–of the sort that nobody buys because it doesn’t ziplock but somehow you’ve got a hundred of them and you’re not throwing them away–and line your cube with it.  After lining, you push the Popsicle sticks into the groove that once held the lid of the cube keeping the chocolate fresh.  The sticks make a press fit–and that’s the ticket to creating a wonderful self-locking-in-place drip edge that you can wipe a paint or varnish brush against as you work.  You’ll feel really clever that you found a purpose for your Trader Joe’s cubes, Popsicle sticks, and those non-zipping plastic bags that you really have no other use for but can’t seem to throw away.

At the end of the day, you let your cube sit so the varnish hardens in the plastic baggie.  In the morning, your Popsicle sticks will have a dry layer of varnish on them so you’ll remove them, replace the baggie with a clean one, push the sticks back in place on top and put your new varnish in your cube for the next day’s work.  Believe it or not, you can do this for days–or weeks in my case–as you work your way around the boat putting on your layers and layers of varnish.  No real cleaning required, either. If you’re really good, you only use one or two of your cubes and 4 to 8 Popsicle sticks.  If you’re a little messy, you might go through twice or thrice the quantity.  If you’re careless and you’ve been eating a lot of chocolate and lime-bars, well, it’s not that big of a deal to go through many, many more.  The baggie is the key to it all though.  A daily baggie keeps everything clean.  During my varnish-fest, I usually don’t clean my brushes but instead I store daily in a container of turpentine.  At the end of the -fest, I can do a cleanup of it or if I’ve been using an inexpensive chip-brush, I can throw it out. For painting, I tend to clean it or throw it out daily.

masts in the sky

The Power of Raspberry Pi–MythTV tweaks and techniques

This post continues my previous ramblings about using the Raspberry Pi aboard the boat.  To start this story at the very beginning, go to this post. To go to the previous post in this series, go here.

Screenshot of MythWeb running on Raspberry Pi 2

Now to discuss some lessons we have learned about using our RPI-2 with MythTV aboard Schooner Mahdee to record over-the-air TV broadcasts for later viewing: Why record when so much is available instantly over the Internet?  Four reasons:

  • we are often anchored where Internet access is unavailable, or the speed is too slow to stream video;
  • we pay for high speed (4G) access per gigabyte;
  • broadcast HDTV provides an effectively free source of additional bandwidth and the HDTV programming is often many times much higher resolution than via Internet streaming;
  • those shows can be saved on a hard drive for later viewing anywhere and anytime.

Stunningly beautiful full 1080 HDTV programming is often broadcast and can be saved for later viewing on a big vibrant HD computer monitor–even in places with no Internet at all.  Those very high resolution shows consume around 5GB per hour.  If using our 4G hotspot, at that rate, our entire monthly Internet bandwidth for work and pleasure is equivalent to a couple of HDTV movies.  By comparison, in some locations, we can record HDTV shows around the clock for free–an incredible deal!  In practice, each 24 hours of saved H-264 encoded HDTV recordings exceeds our total Internet bandwidth usage for the entire month. Our only cost is for the hard drives and each $150 hard drive can save thousands of shows and take up less space on the boat than a small paperback novel.  So, even when we could stream videos over the Internet, we rarely do.

Since we obviously travel a lot, our settings for MythTV are not set and forget–in contrast to more stationary users.  We use Antenna Web in each new location to determine where HDTV transmitters are relative to us and how well we can expect to receive different stations.  We have both an omni-directional and a directional gain antenna to choose from.  Spinning around on a single anchor makes the directional antenna unusable, but if the boat is fixed in orientation with multiple anchors or shore-tie, we can use it to increase reception of more distant HDTV stations.  Sometimes we can get great reception with the antenna below decks in a stealth mode.  For more challenging stations, reception may require an antenna be raised on a flag halyard–not so stealthy.

We have an inexpensive account at Schedules Direct which interfaces very well with MythTV.  With an Internet connection, we generally upload new schedule data every day or two.  There is limited (just the next 12 hours) program schedule data provided for free by the stations themselves on the transmitter frequency using EIT, but scheduling works best with longer range data and Schedules Direct provides about two weeks of scheduling. That data also includes lists of actors and other credits as well as descriptive information which we retain with our recordings and in a separate custom Ruby-on-Rails (RoR) web interface and database.

Schedules Direct also allows us to have four different locations in our profile.  Thus, we have one for each major city area we typically visit.  In those profiles, we can remove stations we do not want–such as those without English language audio–and our custom settings will persist until our next visit to that area.  I am constantly amazed at the number of over-the-air broadcast stations we can receive even when we are far from a metropolitan area.

With our large MythTV database of over 10,000 previously recorded shows, nearly 100 channels of available broadcast programs in many locations, and large number of rules and priorities about what we want to record, it can take several minutes after starting the MythTV back-end for it to figure out what to record. During that time, the MythTV front-end and MythWeb browser interface running on the RPI-2 will will show no scheduled recordings. Whenever possible, I use the command-line mythtv-status to see what is in the recording queue rather than running the more resource-intensive front-end. Even mythtv-status can take several minutes to complete and will show that nothing will be recorded until all of the data has been parsed and prioritized by the MythTV back-end.  Loading new schedule data from Schedules Direct can take nearly 20 minutes to process on our–admittedly overloaded–RPI-2. Sort of like sailing tack to tack to get to one’s ultimate destination, patience is required and one can not expect a newly added show to be put into the recording queue right away. I plan for the RPI-2 to take up to five minutes before a new recording is reflected in the queue.

With an Internet connection, MythTV gets program meta data for each recording so that we have images of cover art–which makes the front-end display nicer.  MythTV can also flag commercials so that they can be easily skipped during replay or even removed from the file entirely.  Commercial detection is very resource intensive, so we set MythTV on the RPI-2 to not do any commercial detection on the recordings. With this setup, the RPI-2 is also very useful as a desktop computer for me to browse the Internet using Firefox/Iceweasel, read and write email and other miscellaneous things all while displaying current weather data and monitoring anchor holding.

One glitch that I have encountered is that the MythTV startup script does not always work in Debian Jessie due to incompatibility with SystemD. The symptom is that the startup script completes with no errors, but the back-end is not running–starting and restarting MythTV using has no effect. The problem seems to be related to the init-functions command. Adding the following just before that call in /etc/init.d/mythtv-backend as follows helped:

_SYSTEMCTL_SKIP_REDIRECT=true
. /lib/lsb/init-functions

Then that fix failed so I am now manually starting MythTV using the old InitV command:

/etc/init.d/mythtv-backend start

It is also good to ensure that MythTV is not running before starting it and to make sure there is no file named /var/run/mythtv/mythbackend.pid. First kill hung processes and then check for the pid file and delete it if necessary before staring MythTV using the above command. Since I rarely reboot the RPI-2, manually starting MythTV works fine and the InitV command is trouble free.

Another glitch is that the HD HomeRun recordings sometimes fail leaving MythTV thinking the recording is still happening. After upgrading the HomeRun to the latest firmware, this situation happens less often. Still, every few days I need to stop MythTV and wait for all the threads to be killed and then restart MythTV.

Next, I will cover some system-wide optimizations that we have made that make MythTV more reliable given the highly loaded RPI2 we run it on.

Addendum: this conversation continues on our technology-focused website Windward Ho!

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