We have been a bit quiet–but busy–during our stay here in Annapolis. A couple significant projects were done, and a bunch of minor ones.
Avoiding Weak Links
The road trip project was our anchor chain. It was inexpensive chain when we bought it, primarily (we have since learned) because the galvanized surface was applied by electrogalvanizing instead of hot dipping. After two and a half years of service, the galvanizing was gone from much of the length of the chain, and it was actively rusting. The rust was not (yet!) severe enough to impact the strength, but is was certainly bad enough to make a mess on deck every time we hauled the anchor.
Electrogalvanizing is the process of using an electric current to plate a thin layer of zinc onto steel. It gives a nice smooth surface, and is quickly and easily done, but the layer of zinc that results is very thin. The resulting product is generally not recommended for highly corrosive environments. Certainly there are not many environments that are more corrosive to plain carbon steel than soaking in salt water! “Hot-dipping” is literally soaking the clean steel in a vat of molten zinc. It results in a much thicker, although rougher and less attractive surface. Live and learn: Do not consider anything except the hot-dip process for galvanizing anchor chain.
When we bought the existing chain about two and a half years ago, I had looked to find a place to see if we could have the old chain regalvanized, but had no luck with finding an economical source. This time I found Baltimore Galvanizing. In their shop 300 feet of chain and the anchor would be priced as a “small job” and be charged the shop minimum of about $300. Compared to $1800 for new chain, this was sounding pretty attractive. Especially considering we could throw in the anchor and have it done as well.
We were lucky enough to have a friend visiting us who had that most valuable of things a friend can have: A pickup truck! We loaded the chain and the disassembled anchor onto Aras’ truck and drove the 45 minutes to the back corner of an industrial section of Baltimore and left the chain with them, and were promised about a week’s turnaround.
A week (and a day) later… it was done. By this time Aras has left, so we needed to rent a truck to pick up the finished project. Back to the marina, and we load it into the dinghy so we can easily load it back onto Harmonie.
The anchor did not really require regalvanizing yet, having been hot dipped when it was made, but it was showing some wear, and we could add it to the job for no extra money, so why not? On the anchor, we decided to replace the bolts rather than have the old ones reglavanized. The original bolts from Mantus were Grade 5 galvanized bolts. We replaced them with “structural bolts,” also galvanized, and Grade A325. A325 steel has the same strength specifications as Grade 5, the primary difference is the bolts have an unthreaded shoulder, which increases their shear strength.
There were about a dozen places along the 300 foot of chain where the zinc coating had “glued” together the links enough that they had some trouble going through the anchor windless. A couple whacks with a hammer, and those came free easily. The significantly rougher, lumpier surface of the hot-dipped chain compared to its old electrogalvanized finish means the chain does not “flow” as well and makes a significantly taller, steeper pile as it comes into the chain locker. This really isn’t an issue on Harmonie because the Amel Super Maramu has almost 4 feet of fall beneath the chainpipe. This should get better with use, as normal friction in handling wears off the larger lumps and bumps.
Overall, this was a very satisfying project. We spent less than 25% of the price of a new chain, including the truck rental, and we have a chain that should give us years of service before needing to repeat the process.
Keeping the Cold In.
The most time consuming of our projects was a complete replacement of one of our old chest freezers. The original box as constructed by Amel was not very well insulated to start with and after more than 25 years the insulation was saturated with water from condensation. The result was we consume a lot more power keeping it cold than we should and we also had problems with keeping food fully frozen.
The new freezer compartment was insulated (mostly) in vacuum panels, and was basically constructed of a box of 5mm epoxy coated plywood, a layer of insulation, and a second inner box of more 5mm epoxy coated plywood. Easy to build with strong, inexpensive, good looking, and readily available materials. Hinge and latch hardware were reused from the original.
The vacuum panels we used for insulation are made by Panasonic for high tech building and refrigeration insulation. Panasonic claims they will have at least half their insulating capacity remaining 12 years out. One inch thickness of these panels is rated at R60, roughly the equivalent of a FOOT of high quality polyurethane foam. The do require care in installation to be sure they are not subject to any kind of mechanical damage that could puncture the skin. Also, they are available in a limited range of sizes, and can not be cut or trimmed, so designing something to fit in an existing space can be a challenge.
In addition to the greatly improved insulation, we designed a double gasket system to make sure the warm air stays out, and the cold air stays in, where they belong. A system of plastic baskets also helps organize the food storage, and allows excellent circulation of cold air helping to avoid the warm spots that plauged the old box.
As cooler autumn weather takes hold, it is time for use to begin our southern migration. We will start moving in four or five days down the Chesapeake Bay. We will most likely pause at Norfolk, VA and hold for weather. From there, to Hilton Head, SC, then to Brunswick, GA, then to Fort Lauderdale, FL, then to the Bahamas at the end of December. From there, we really do not yet have firm plans.