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Lovell: "Ah, Houston, we've had a problem. (pause) We've had a main B bus under-volt."

CapCom : "Roger. Main B under-volt. Okay stand by 13, we're looking at it."

Haise: "And we had a pretty large bang associated with the caution and warning there."

Haise: "Yes, we got a main bus A under-volt now too showing."

CapCom: "Main A under-volt."

Lovell: "Okay. (pause) And it looks to me, looking out the hatch that we are venting something."

CapCom: (over Lovell) "Roger."

Lovell: "It's a gas of some sort."

CapCom: "Power down until you get an amperage of 10 amps less than you have now."

Swigert: "Roger, Jack, we're doing it right now"

Extract of the actual transmissions (not movie dialogue) of Apollo 13 on the failure of their electrical system

Judy and I strongly identify with the aborted Apollo 13 moon mission, not so much because of our years of work in the aerospace and defense, but rather because we had a moment not unlike the crew of Apollo 13 in June of 1990 during our participation in the West Marine Pacific Cup race from San Francisco to Hawaii. Four days out, 300 miles offshore and about 300 miles south of San Francisco, just as we were getting ready to catch the trades toward Hawaii, during the middle of the night the lights on our instruments began to dim. Although not as dramatic as the explosion on Apollo 13, the importance was no less significant. It turns out that our fairly new Alternator (which charges the batteries) had internally failed and had not been charging our batteries. We had loaned our old one (read spare) to a fellow short-handed racer and our batteries were nearly depleted. The result was not only had a year of preparation for the race ended but we actually found ourselves in a fairly dangerous predicament.

Appreciate in 1990 there were no magic hand held battery powered GPS units that give you your exact position, no power efficient LED lights, and no battery powered Iridium satellite phones for communication. Perigail was a modern boat for the time, she was equipped with Transit Satnav (a predecessor to GPS), had the best Shortwave Radio money could buy, and even the propane for the stove was controlled by an electric solenoid. Without power we didn't know where we were, we had no light and we couldn't even heat up our food which was mostly frozen. Not a good situation.

Although it was one of the most physically and mentally challenging times of our lives, we did make it safely back to San Francisco through a combination of good luck, good seamanship, and the sound hull of our beloved Perigail. Although it was a hugely painful lesson (to this day Judy and I are still deeply disappointed we did not make it to Hawaii on Perigail), it was an incredibly valuable one that has made us insistent that “Failure Is Not An Option” when it comes to the electrical system on Makara.

The subject of boat electrical systems is one of the most passionately discussed subjects within the cruising community. The choice of battery construction alone (Lead Acid, Gel Cell, AGM) is a subject debated with religious fervor. It is also an area where some brilliant books have been written, most notably Nigel Calder’s classic “Boatowner's Mechanical and Electrical Manual”. I would be incredibly arrogant to debate a subject that others much better qualified that I have written about. I will tell you, however, what we have decided to do on Makara, with the understanding that we have taken the “Failure Is Not An Option” mindset to some extremes.

Makara’s electrical system has been designed to be highly redundant. We have LOT’s of batteries using the mindset that we will rarely have the big yellow cord (Dock Power) hooked up, and when we do we have to accommodate power from anywhere in the world, and that Makara’s systems need to be protected from that power. We have also taken the mindset that we need to be able to charge all those batteries in multiple ways. Last, because of some of the marvelous advances in lighting and power conversion technology, we are designing Makara as a VERY energy efficient boat.

Batteries
I have done a huge amount of research into batteries, and as I mentioned the subject area of battery construction is debated with zealous passion. Our choice of battery type has actually little to do with the subtle advantages of one type of construction over another. What I care about is if a battery fails (remember Failure is Not An Option), what battery can I most easily get a replacement for ANYWHERE in the world. As a result we have chosen to use the lowly lead-acid golf cart battery (specifically a T-105 6V battery) as the main house battery on Makara.

Battery Type	T-105 6V	4D 12V	8D 12V
Amp Hours	225	183	225
Weight	64 lbs	130 lbs	161 lbs

Why the golf cart battery?  Well, golf carts (not necessarily golf courses) are pervasive around the world, and in the most isolated place you can imagine, if there is civilization there, I can probably find a golf cart battery. A second reason I have chosen this particular battery (versus a 4D or 8D) has to do with our physical strength. I can lift a 64lb T-105 battery up and out of the battery well. I can’t lift a 130 lb 4d or a 161 lb 8D.

Another reason I like this particular type of battery is that it is designed for true cruisers who will be constantly cycling the batteries. This requires a bit more maintenance (you must top them off with distilled water occasionally), but you can expect a long service life out of them versus other higher tech options which are great for dock "Queens" (whoops, I am stepping into religious territory here).

We have also decided to use a very common Group 31 deep cycle battery for starting the engine. In fact we will have two of them, a primary and a back up. If worse comes to worse we can even start the engine with the house bank – belt, suspenders and a second pair of suspenders.

Size Matters
Neither Judy or I like the sound of an engine – we are SAILORS after all. As a result we don’t want to have to spend hours charging our batteries every day. Further it is VERY difficult to fully charge a battery bank, however it is very easy to get a battery bank charged to about 80%. Given that we have conservatively estimated that our power usage will be about 250A/hrs per day, we have sized our house battery bank at  900A hrs – or eight, yes count them eight, T-105 batteries independently isolatable in 4 sub banks. With this much energy stored, we expect that under normal circumstances we may be able to go three or four days without needing to charge our batteries – usually enough power to get us to shore from most anywhere. For those "in the know" we are treating all the batteries as one large bank under normal conditions. The sub-banks are to allow disabling a bank if a faulty battery is suspected without physically rewiring the batteries like the bilge rats you see in old submarine movies. Bear in mind that after our Pacific Cup experience and our objectives for Makara we don’t want to find ourselves in a situation without power. Unlike Perigail where we were in a relative controlled situation, we don’t want to be, for example, in very high latitudes without power as this could truly create a life-threatening situation.

Charging
Makara is very much like a space ship. She is a self contained world designed to go for months, or years, without the Big Yellow Cord, connected. As such her ability to generate her own power has to be reliable, redundant, and efficient. Our approach to this has led us to a somewhat unusual choice (but based on an idea we got from Nigel Calder when he was building Nada, his Malo 46) which is to install a DC generator on Makara. Many boats have AC generators to power all the conveniences of the modern world from Air Conditioning to Washers and Dryers. We have designed Makara as a “green” boat with very few AC needs and as a result we don’t have a need for an AC generator. This has given us the opportunity to install a DC generator whose singular purpose is to be the primary means to charge our bank of T-105 batteries. The advantages of this are several fold: The DC generator is VERY efficient – generating nearly 200AH of power on only 0.2 gallons of diesel fuel. It is also very simple – basically a highly reliable single cylinder diesel engine (6 hp Kubota) and an alternator. Lastly, by comparison to Makara’s engine, or a normal AC generator it is much more quiet when properly installed.

In addition to the DC generator, we can also charge the Makara battery bank from the 75HP Turbo Charged Yanmar diesel engine. In general, because it is inefficient and doesn’t make the engine happy to be run without being under load, we would only do this while motor-sailing, or in the event of a catastrophic failure of our DC generator.

Judy and I like the idea of also having non-fossil fuel based alternatives to our primary power generation systems. After all diesel is at $3 a gallon and rising, and there are occasionally spot shortages. As a result Makara is being built with THREE separate non-fossil fuel charging systems. The first, fairly common among cruisers is an Air-X wind generator which is capable, when the wind is blowing and mainly while at anchor, of generating upwards of 4+ Amp hours of power under fairly normal 15 mph wind conditions. The second, also fairly common, are two 45 Watt solar panels which conservatively should generate 7 Amp hours of power on a sunny day – enough to run our lighting for an evening or to keep the batteries topped off while we are away from the boat for a few days. The last, and perhaps the coolest, is a towed generator which while Makara is underway will generate 1 Amp of power for each knot of boat speed, which for Makara is about 7 Amps or enough during long passages that we should be able to largely avoid using our fossil fuel generation capability at all.

In total we have 5 independent sources for generating power on Makara.

AC/DC
For those rare occasions when Makara is hooked up to dock power with the BYC (big yellow cord) we have done something a little unusual to make sure that Makara’s can feast on the wide range of voltages and quality of power from around the world and to insure Makara is protected from those variations. Makara, unlike most boats of her size, is being built with only a single 30A inlet (most boats her size have dual 30A or 50A inlets). That’s because the only thing that runs directly off dock power on Makara is the Water Heater and the Battery charger. All the other AC outlets on the boat a supplied by a Charles Industries true sine wave 3200W DC to AC inverter. I know this may seem a little funny but it allows me to insure that my AC outlets are always clean US style 120V 60Hz AC power – not the voltage and frequency du-jour of the country we happen to be in.

Dock power first comes through a large 3.5kW Mastervolt isolation transformer that allows us to both isolate the AC power from the dock (preventing electrolysis and other really bad things) and to convert the power to something approximating 120V (actually 90v-140V) at whatever the local frequency is (50-60Hz). That power then supplies our Charles Industries 30A battery charger. Sure AC to DC back to AC conversion is a little inefficient but it allows Makara to safely hook up to dock power EVERYWHERE in the world – and if you want to see the variations in power check out the links at the bottom of this article.

Building Green
Oddly enough during the melt down of our power system on Perigail many years back the one key safety item we really sweated we needed power for was also one of the most power hungry – the Navigation lights (those red, green and white lights that theoretically tell other vessels not only that you are there, but what kind of vessel you are at night). Conventional navigation lights during 10 hours of nominal darkness will consume 30Amps of power – that is huge. When we were specifying Makara Judy came across a new generation of LED navigation lights that only use 1/8th that power yet meet all the requirements for visibility.

In addition to Navigation lights some remarkable advances in white LED cabin lights have occurred – mainly in brightness and color, in just the last year. As a result Makara is being built with LED cabin lighting (both conventional white and red for night usage) throughout.

One of the other power hungry items on a conventional boat is the autopilot– which drives a very power hungry hydraulic RAM to steer the boat. Although this may seem like a luxury, bear in mind no sane person actually steers a boat 24 hours a day during a long passage. Judy and I got introduced to something called a Monitor Wind vane two decades ago which uses the power of the boat moving through the water and a very clever mechanical mechanism to steer the boat on most points of sail. As a result under most circumstances rather than spending 120 Amps a day running the autopilot we don’t have to use any power at all.

A summary of our Makara’s power budget versus a “conventional” boat can be found at the below.

Item	Hours/Day	Conventional	A Hours	Makara	A Hours
Nav. Lights/Lighting	10	8	80	1	10
Appliances/Refrigeration	24	10	240	6	144
Instruments	24	3	72	3	72
Autopilot	24	5	120	0	0
Total		26	512	10	226

Dealing With Failure
I can remember that the night the power failed on Perigail that we were almost in a panic trying to figure out what was wrong. Documentation of the electrical systems was poor, really just a collection of manuals, the primary wiring was unlabeled and difficult to access and I honestly really didn’t understand the systems at a detailed level. The bottom line was that if we were on Apollo 13 we would not have made it back home.

As redundant as the systems on Makara are, we are also considerating how to deal with failure. We are thoroughly documenting the systems, we are insuring that every wire is labeled, we are insuring that there is easy and straightforward access to it’s components, that systems can be isolated from one and other to aid in diagnosis and repair, and lastly that both Judy and I understand those systems as thoroughly as we do the things that make her sail.

I know from decades in technology, that Murphy is always present, and that NOTHING is fool proof. We can protect against it, but in the end if something does go wrong, I want to be able to either fix it or mitigate its’ effects. Last, if something catastrophic happens (a lightning strike comes to mind), unlike Perigail, one of the first things that gets installed on Makara is a kerosene lamp – I really hate the dark.

If you want more detail on the electrical system of Makara follow this link to a set of PDF schematics of Makara’s electrical systems: AC System, DC System

Copyright ©2005-2010 N. Daniels & J. Edwards, All rights reserved.