What comes in must go out

A sailboat is a small, self-contained world.  Because of this, the consequences of the lifestyle decisions we make on a daily basis are much more in-your-face than when living ashore.

As an example, think of a sailboat as a closed system (that's actually pretty easy to do).  Everything that comes aboard will eventually need to be removed.  Unless, that is, it is destined to become part of the boat, and this has to be a very limited set of things, or we will sink! 

I think I first had this realization early in my liveaboard career, when I was cleaning the floor.  Anything I missed was eventually going to find its way into the bilge, and then overboard via the bilge pump.  But bilge pumps are kind of finicky - for example, they don't like hair at all!  It gets wrapped around the driveshaft and the impeller, eventually bringing the pump to a halt.  I started viewing the cabin sole as the last-ditch bulwark keeping hair out of the bilge.  The hair still must leave the boat, but hopefully now via a full shop vac.

The closed nature of a boat system is nowhere more obvious than with garbage.  Every bit of packaging (and make no mistake - packaging is by far the bulk of it) must first be carried down the dock to the boat, and then carried back up the dock to either the garbage dumpster or the recycling dumpster.  Why do we have so much packaging?  Cellophane wrappers over cardboard boxes over plastic internal bags. 

(Aside:  Thank heavens our marina provides a recycling dumpster.  It seems that it fills up nearly twice as fast as the garbage dumpster.)

It seems that every time we head up the dock, there is something to be carried up to the dumpsters.  There is no dockside garbage service - there's just us.  More than once I have wished that there was a sheltered station by the recycling dumpster where I could remove the unnecessary layers of packaging before hauling things down the dock.  There would be less to haul (two ways!) and there would be more room aboard.  Or better yet, how about locating that station at the grocery store?

This is another instance where living on a boat brings the consequences of your lifestyle decisions directly to you.  Realizing that I've come at this obliquely in some other postings, I have created a new tag, footprint, to flag them.

What comes in must go out

Watt's Your Energy Budget?

Now that we have common ground on the meaning of energy, we can discuss an energy budget. In this discussion we will use the "bastard unit" of amp-hours as a stand-in for energy.

Why not use the real energy unit: watt-hours? Because it is easy to say something like: "My refrigerator draws 30 amps, and I need to run it for about 2 hours/day. Thus it uses 60 amp-hours per day." In the real energy units of watt-hours, the refrigerator uses 30 amps x 12 volts x 2 hours = 720 watt-hours. Tho this is correct, it is one step removed from those things that are easily measured, and differs from the amp-hour value only by a constant: the system voltage.  So we take a step back from correctness in favor of transparency.

So let's run thru an analysis. On our hypothetical boat, Hypothesis, we find these things which use electrical energy:

12 Volt Consumer	Amps	Hr/day	Amp-Hr/day
Refrigerator	30 amps	2 hours/day	60 amp-hours/day
Water Maker	6 amps	4 hours/day	24 amp-hours
Autopilot	6/0 amps under way/at anchor	?	24/0 amp-hours (est) under way/at anchor
Instruments & GPS	2 amps	24 hours/day	48 amp-hours
Interior Lighting	5 amps	4 hours/day	20 amp-hours
Anchor Light	2 amps	0/8 hours/day under way/at anchor	0/16 amp-hours under way/at anchor
Navigation Lighting	4 amps	8/0 hours/day under way/at anchor	32/0 amp-hours under way/at anchor
VHF	0.5 amps (RX)	24 hours/day	12 amp-hours

Wow. Hypothesis shows a total daily consumption of energy of about 220 amp-hr while under way, and about 180 amp-hr while at anchor. These are substantial numbers. If Hypothesis carries (let's say) 600 amp-hours of battery capacity, her owner might still be feeling pretty smug. But most experts seem to agree that regularly drawing down your batteries more than 50% will severely shorten their lives. Uh oh... now we are looking at a daily energy consumption which runs 60% to 73% of the available storage capacity.

So unless we replenish energy, we'll run out sometime in the second day. Not looking good for that long cruise at all. Here are some ways to replenish that 180-220 amp-hours every day:

Run the engine.

If you have a 180 amp alternator, you'd think that an hour would do it. But the alternator won't be delivering energy at it's rated output for that full hour - it will fall off as the batteries charge up. Figure two hours at a minimum

Solar Panels

Assuming that Hypothesis owner bought 4 large panels that are rated at 15 amps, all she'd need is 3.6 hours of sunshine per day. But that rated output is at "full sun", which you can read as "noon in the tropics". If Hypothesis were in the tropics, those 4 panels would probably take care of her pretty well, given that she will have a lot more than 4 hours of fairly direct sun and even more hours at a less than optimal angle. The crew's job would be to keep adjusting those panels so that they are perpendicular to the incoming sunlight thru the day, and to make sure that nothing shadows a panel. Cloudy days present a problem, of course

Wind Generator

Most of these are rated at 300-500 watts - let's convert to our units: dividing by system voltage, 25-42 amps. Now that rating is probably at 25 kt, which we hope Hypothesis is not spending days on end in. So let's cut that in half for a more realistic estimate of power output - say 10-20 amps. The beauty of the wind generator is that it continues day and night, as long as there is wind. The wind generator could easily handle the load.

But the first thing that should be done aboard Hypothesis is to try to reduce the energy consumption.

• Replacing all the lights with LED bulbs will make a very significant dent in the budget.
• Drink warm beer and turn off the refrigerator. The refrigerator is the largest single energy consumer on this boat.

Many cruisers seem to use a strategy employing all of the above: They reduce consumption as far as possible. They run the engine occasionally. They have solar panels, and they have a wind generator. Hypothesis should be able to make her cruise after all.

Note that in all of this, I have purposely left out mention of an inverter. Inverters are wonderful inventions, allowing use of 120V appliances with a 12V energy source. But here is where our "bastard unit" of amp-hours can get us in trouble. Remember I said that we could just ignore the system voltage because it was constant? Well with the inverter in the equation, that is no longer true. Here's how to figure your 120V energy usage:

1. Look for the tag on the 120V appliance where it's rate of energy consumption is specified. It will most likely be in watts (or kilowatts: 1000 watts). Sometimes it is stamped or molded into the bottom or back of the appliance.
2. If the tag denotes watts, just divide the wattage by 12, and you will be pretty close to the 12V amperage required to feed this 120V appliance thru the inverter.
3. If instead you find a rating in amps, multiply it by 10 and use that as the 12V amperage required.

(Here, near the end where most people will have given up reading this, I shamefacedly admit that Eolian's energy budget includes 16 amp-hours/day for the making of lattes in the morning, using the espresso machine thru the inverter.)

Also note that an inverter draws power all the time it is on, even if there is no 120V load. But most likely there will be a few "wall bricks" plugged in somewhere, increasing the load. Turn off the inverter when it is not in use.

If you are doing an energy budget (or cruising!), there is one instrument you will want to install: an amp-hour meter. These directly read out the amp-hours consumed from (or fed into) your batteries. Having one on a cruise is having a "fuel" gauge for your electricity storage. And having one before the cruise allows you to get a firm handle on your consumption. I highly recommend it.

Those 600 amp-hour worth of batteries on Hypothesis could store a total of 600 x 12 = 7200 watt-hours, or 7.2 kilowatt-hours. You could buy this energy from your local power company for about $1. Instead, managing it yourself onboard is a *BIG* deal. Life is sure easier ashore.

But life offshore is well worth it.

Watt's Your Energy Budget?

Project: Replace the Holding Tank

(Project from 2003)

Now here is a project you never want to do.

This is an uncomfortable subject, but then living aboard forces you to come face to face with most of the aspects of your existence, many of which are "out of sight, out of mind" on shore.

I don't know how long it has been illegal to discharge sewage into Puget Sound, but it has been a long, long time. Accordingly, boats are required to retain sewage and carry it around in a holding tank. I want to invite the folks on shore who are always saying that people who live on boats are polluting the Sound with raw sewage to my next "Replace the Holding Tank Party".

Our holding tank was made of aluminum and was 20 years old. It had begun to seep, especially where someone screwed a bronze fitting into it, causing galvanic corrosion. It needed to be replaced.

First: accessibility. The holding tank is in a small bilge compartment amidships. There are two hatches into this compartment, but neither is very large. Initially, I carefully measured up the space and the hatches and sent the measurements to Adam, who put them into a fancy CAD program. I then gave him a tank catalog (Ronco Plastics has a great catalog!) which he then used to determine which tank(s) might be able to fit thru the hatch, and could then be rotated into position. As it turned out, only very small tanks (less than 20 gallons) would work. So we bit the bullet and cut out the section of floor between the hatches and removed the supporting 4x4 teak beams underneath (the aft beam is still in place in the picture). Now the opening is large enough to accommodate a tank of realistic size: 45 gallons, the same as the existing tank.

Thankfully, there are no pictures of the next step. As preparation, we pumped and rinsed the tank repeatedly, then dumped a gallon of bleach into it and filled it again and left it to steep. Then another pump out to get rid of the bleach solution.

Now the steps were these:

• rent a SawzAll (not gonna use any of MY tools for this...)
• put on old clothes
• climb down in the hole
• cut the tank up
• hand the pieces to Jane

Now mind you, there was only a little smell initially, but after the coating on the inside walls was disturbed, and after the 2" of sludge in the bottom started sloshing around, it was a totally disgusting job. After all the pieces were out, I sloshed bleach over everything and then scooped up the remainder into a bucket. Yes, there was a lot of misc. "stuff" around, behind and under the tank. Then hose out the area after the bleach swab-down. Then shower. Shower. Shower again.

There is a lot more room down there now...

When the custom-manufactured tank arrived (only a week after ordering - Ronco is great!), it barely fit into the back seat of the Fox. It is a rotationally molded polyethylene tank, with 3/8" wall thickness.

The new tank goes on the port side of the compartment instead of the aft bulkhead. In order to keep the tank in place, a substantial framework had to be built and fiberglassed to the hull. One should remember that when full, it will weigh over 400 lb, and will attempt to jump around down there in a seaway. A loose, full holding tank is a thought I really don't want to contemplate.

As the construction proceeded, lots of trial fittings were required, each a fairly major ordeal. For the final fitting, the plumbing was attached (it couldn't be done when the tank was in place), and the tank was installed.







For completion, 2x4 keepers were screwed in place trapping the tank. You can also see that we gave the entire bilge compartment a couple of coats of white paint, which improved appearances immensely.

Final steps: I cut thin (less than 1/8") teak strips and attached them to the raw edges where the floor panel had been cut out. I reinstalled the floor panel, plugged the screw holes, and applied varnish to the unfinished wood. And then finally, sand/refinish the entire floor in the office area to incorporate the newly finished areas.

Project: Replace the Holding Tank

Conscious Consumption: Living on 30 amps

The yellow shore power cord that connects Eolian to the dock power is an electrical umbilical cord - it brings in all of the electricity we use at the dock.

Now, it has been a long time for most of you since you had to think consciously about how much power you were using in your house. Household power systems have been upgraded to the point where the supply almost always exceeds the possible demand.

Not so here. The shore power cord, the power panel and all the circuitry onboard are designed to handle 30 amps maximum. So how much is that, really?

• Heat pump: 12 amps
• Refrigeration: 5 amps
• Water heater: 10 amps
• Interior lighting: 4 amps
• Battery Charger: 15 amps
• Espresso maker: 10 amps
• Microwave: 15 amps
• Vacuum cleaner: 10 amps
• Hair dryer: 15 amps

Well. You see the problem. Before you do anything which uses a lot of power, you have to take a look at the power panel, and see what the boat is drawing. You may have to turn something else off. So, for example, when you ladies want to use the hair dryer, it is typically right after taking a shower - which means the water heater is running, since it was depleted supplying hot water for that shower. It is cold outside, so the heat pump may be running too. That is 22 amps, just for those 2. Typically, I shut off the water heater while the hair dryer is running. Of course, the trick is to remember to turn it back on when you are done.

Off the dock, the equation changes. The limit doesn't change, but the supply does. Most of the boat is set up to run off of 12 volt power, and we have 8 large batteries onboard to supply that power. To use battery power to run standard 120VAC appliances, we have a large inverter, which transforms 12VDC into 120VAC. A 100% efficient translation of power like that says that (volts x amps) on the input side of the inverter must equal (volts x amps) on the output side. Therefore, since we are stepping up the voltage by a factor of 10 (12V -> 120V), the input current must be 10 times the output current. This means that your hair dryer, which pulls 15 amps at 120VAC, is pulling 150 amps out of the batteries. This is a huge load - twice what the starter in your car pulls when starting it, if you have a V8. Imagine cranking two recalcitrant V8-equipped cars continuously the whole time you are running the hair dryer. So running big loads off the inverter is possible, but uses prodigious amounts of battery power. But running the espresso maker every morning is not optional on Eolian.

Therefore, we also have a generator onboard. It is diesel fired, produces 30 amps at 120VAC. But it disturbs the serenity of a quiet anchorage, so I try to minimize its use. It is the choice if we need the hair dryer (its noisy too...). It also supplies the battery charger so that when the generator is running, the battery banks are recharging.

So, typically the electrical budget when we are off the dock requires about an hour of generator in the morning and 30-60 minutes again at night. The output is essentially directed into the batteries to replenish what has been taken out by the daily operation of the boat. You learn to think in terms of amp-hours at 12 volts. Refrigeration uses 60-100 amp-hours per day. Making the obligatory two rounds of lattes in the morning uses about 20 amp hours. Running the anchor light all night used to use about 15 amp hours, but now we have an LED anchor light that uses about 1/10 of that - small enough to be ignored, and a blessing.

If we run the engine that day, the engine alternator will typically eliminate the need for running the generator

Its a lot easier when you just have to pay the power bill once a month, isn't it? Living on a boat is a lot like that in many ways: You are, and must be consciously aware of things that are invisible, behind the scenes, ignored, on shore.

But being conscious is a good thing, I think.

Conscious Consumption: Living on 30 amps