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2013-04-11

Swinging the lead as little as possible

We are choosing to call that dark debris "silt". It's not silt.
A "winter storm in spring" is currently battering Toronto, increasing angst and frustration with our rehab pace and, because there is actually ice on the sidewalks, roads and Alchemy's decks, increasing the danger of even going up the ladder.

It is also 10 degrees too cold to paint. Argh.

So readers get an update today that combines a limited amount of actual progress with some anticipated directions that progress will lead.

That's "lead" as rhymes with "bleed", not "lead" as in "red".

The author demonstrates the hazards of working with power tools.
The first photo is the freshly removed section of Ghost Tank top plate, which ate about three 3/32 inch cut-off disks as spun by my venerable and compact 4-inch Makita grinder. That is,  until I switched to the beefier 4.5 inch Mastercraft "expendable" grinder and its 1/4 inch disks. The second photo shows what happens when a contra-rotational "skip" of the grinder shatters the disk and sends the pieces, Enter the Dragon-style, into flesh. The pants, they did nothing!

However, the plan to leave a five-centimeter "lip" around the tank means my clown shoes can still fit on the remainder of this tank, and I can access the debris and rust successful. When it warms up enough to paint, that is.

After much dithering and cross-eyed readings of MSDS sheets, I chose Metal Prep Rustlok 6980, a product that combines the "rust conversion" I desire to lock up the existing poo-tank corrosion and the primer function necessary for whatever topcoat I choose.

Requires a roller, a brush and 10 degrees Celsius
I've used Metal Prep before, primarily to remediate dings on the hull, which are subsequently coated in two-part barrier coat (Interlux, for those keeping notes), and the Endura two-part topcoat that most closely matches the hull colour (number 92, "cream"). Metal Prep covered by Endura and then skinned with very thin HDPE strips and butyl tape sealant is how I intend to both seal and electrically isolate the aluminum roof from the inward-turning mild steel flange of the pilothouse enclosure.

More china than steel plate. A sign you've failed to stick to the maintenance sked.


Back to the ghost tank: We can now scrap the surface of the plate and the more egregious flakes away from the surface and can lower a fan and/or a heat gun to dry out that fairly grim layer of "deposits" at the bottom. I even have a pretty powerful vacuum aboard for that last bit, but it remains to be seen how dried out that layers needs to be to allow full access. And the point of all this? As related previously, THE RUST MUST BE STOPPED on any steel vessel, for fairly obvious reasons relating to sudden onset of non-buoyancy, not to mention beverage spilling and day-spoilage. So the bare minimum for the Ghost Tank is a physical removal of the loose stuff, and a "push brush" technique of slapping on the Metal Prep. Metal Prep likes to be not quite dry when the second or greater coats are applied and that goes for the barrier coat. Whether we will get that period of sufficient warmth prior to launch is still a Known Unknown.

As previously related, it would be nice to have this low and capacious hole filled with fuel, either as a integral tank, or as a box in which a plastic fuel tank squats. An alternative course would be to fill that space with ballast.

It is a somewhat odd fact that 2,000 year old Roman lead ingots are nearly identical to ones smelted last week.

I'm going to assume that most readers grasp the function and desirability of ballast in a sailboat. Alchemy's ballast is internal, unless one considers the solid "box keel" as a sort of elongated fin-thing. The "movable ballast" or "trim ballast" is currently represented by about a half-ton of lead ingots sitting either side of the forward collision bulkhead in the form of what I'm guessing are 50-kilo bars.
Not precisely as pictured, but a potential outcome for the Ghost Tank in one manner or another.
They are where they are because the full weight of tools, spares, lumber, anchors, not to mention the full length of anchor chain are not there. The ingots are to keep the boat on her lines. Throw in two ingots' of tool or spares mass, and logically two ingots can be removed from the forepeak, and either removed or repositioned beneath the center of effort. The salutary effect of ballast here would tend to "stiffen" the boat, make it more resistant to heeling or less "tender".


One could even go for a blend: Coat the tank throughly, lay down a "floor" of lead ingots and lay over that a smaller "daytank" made of HDPE. You would get the weight in the best place, and still have a nice extension of the fuel supply.

Picture this, only better secured and under a set of saloon companionway stairs.
Of course, batteries, being largely made of lead, are heavy, too. It's desirable, therefore, to have them low and, ideally, on the centerline to minimize the chance of spillage of the highly acidic electrolyte.

So it doesn't make sense, nor do we have the time, to make this call before we install the weighty battery bank. Committing to adding ballast aft of the mid-point of the hull, as is this tank space (although not by much) would be unwise. Better to move those lead ingots about (and the tools and forepeak gear in) once the batteries are in place in order to determine further ballasting and trim possibilities. So rust-proofing it is. I doubt I will even restore a new lid...it's just part of the hull, after all.

Regarding the batteries, I've mentioned seemingly crazy numbers of the things we wish to install in the past. It's not particularly crazy, especially if you wish to follow "best practices" in battery reserve power management. One of the best resources I've yet found is at John Harries' superlative Attainable Adventure Cruising website, which has a comprehensive series on the topic. The link is to how best maintain a whack of AGMs, but it's applicable to all boat battery banks and is a good lead-in, no pun intended, to the topic of battery selection, care and usage.

Not to scale, but there are going to be certain similarities to our house bank.


Now, we am buying and installing this summer what would seem to be a coastal cruiser or weekender an insane amount of batteries. We want the ability to run LED lights, our NovaKool reefer, an SSB radio and some occasional (10 seconds of coffee grinder, 90 seconds of microwave, say) inverter-supplied AC loads. I want to be able to do this, at anchor, during five cloudy, windless days during which I can't get much from the wind genny or the extensive solar panels I already have, and during which I do not wish to run the diesel for power or fire up either of the Hondas to charge the house bank.

Of course, I can always do this, or run out 12 NM under engine (and therefore spin high-output alternators for battery "topping up" purposes) and the likelihood of windless, clouded-over days in the tropics are a "worst-case" scenario, but it's a good example of how you wish to think. So, if I use 100 Ah/day, which is pretty low and requires solar showers, foot pumped water and forethought to install micro-draws like LEDs everywhere, in order to draw down 500 Ah over five days, I need a 1,000 Ah bank, which is about 4 x 8D batteries or the equivalent in smaller 6VDC ganged to form 12 VDC "sub-banks". After five days, they would be at 50% state of charge (SOC).

Not good.

Better to have that 1,000 Ah bank and draw down between 100% to 80% between charging opportunities, although it takes some doing to bring a large bank to full 100% SOC, the last few percent being the time-consuming part.

So even though I am proposing a "non-amp-greedy" boat, I am also disinclined to run the engine to make power (but I am entirely happy to make power when I need to motor somewhere) and I am also disinclined to dock for shore power unless it's free/reciprocal, and I don't want more fuel-drinking generator capacity than the Hondas I want to use in place of the inverter for when I want to use a nice, torquey AC-powered tool. Even the ones that can give me vivid injuries.

The battery dimensional have to relate to the carpentry and the need for ventilation, cabling, etc. This is quite preliminary.


That implies a big bank in which the "usable draw-down" is, in fact, a fairly narrow band of potential amp-hours. If you dock or don't mind a genset and have a "diesel fuel credit card", an investment in lead and acid isn't a pressing concern. But it's the admittedly preliminary amp-draw calculations I've made that have driven every other systems decision, down to second pickups in the water tanks to bypass the pressure water in favour of Whale foot pumps.

The big bank is therefore part of the ship-wide internal ballast considerations, just as much as the lead ingot and "diesel tank in the keel" considerations. Or, to take it out of the hull, are the decision where to put the reef points in the main sail.
Basically, ew.
And that's enough blather for a bad day for boat refitting.

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