Most boat horns run off of 12 VDC. The sounding mechanisms they employ are an electrical diaphragm (like a car horn), a piezo (like an emergency buzzer) or an air diaphragm with a compressor (like a truck or ship horn).

A horn is a crucial safety feature when a sudden warning needs to be given, to signal trouble, or when underway with low visibility such as in fog.

Boat horns are available from several well known suppliers, the most famous in marine being the AFI division of Marinco. As the say on their website, they are

…the leading supplier of horns to the marine industry, with over fifty years of experience in designing and manufacturing sound devices specifically for use in harsh marine environments. Stainless steel is used for all critical components such as trumpets, motor cover, diaphragms, and assembly and mounting hardware. In the case of the XLP trumpet horns, the horn is given extra protection through the complete over-molding of the internal motor cover housing. It is this extra process that provides the added protection needed to back up the five-year warranty. AFI offers a complete line of marine horn products designed to meet almost any need, including electric and air trumpet horns, compact horns, electric and air below deck horns, and a comprehensive line of drop-in horns with a wide assortment of grill options.

These inexpensive but often powerful pumps are expected to perform in often varying (and occasionally severe) conditions. Not only are they required to function while a boat is cutting through heavy waves, but also in the middle of the night after a rain storm when the boat is docked and the owner is gone.

The pumps come in a variety of pumping capacities, stated in gallon per hour (GPH), and are usually powered by 12V DC. The methods of wiring them for switching on can be for manual or automatic operation, and most often is for both. Manual switching typically uses a switch on the dashboard. Automatic operation involves the use of a float switch that senses the water level in the bilge. Once a level is reached that can be pumped out, the switch turns the pump on.

Bilge pumps are manufactured by several well know companies, including Attwood Marine. The Attwood Tsunami Series features innovative engineering and compact design, that delivers high output from a small package. Attwood bilge pumps are famous for using the most advanced material available, including the best quality bearings and state-of-the-art brushes, alloys and magnets.

They offer three high-efficiency pumps that move water at output capacities of 500 gph, 800 gph and 1200 gph.

The “prime directive” of marine electrical battery management to to avoid the overuse of this finite power supply, which may eventually compromise an important function, like starting your engine.

Marine electrical battery management can be as simple as monitoring a voltmeter to determine battery voltage; to the use of switches to turn on certain batteries, while isolating others from use ; to having sophisticated voltage sensitive relays that will do the job of monitoring levels and switching batteries on and off automatically – often called a Smart Battery Switch.

Any boater that will be spending time at anchor running electrical accessories, like stereos, will need to maintain some awareness of the condition and level of their battery supply and life. The inability to restart an engine (which is a key source of recharge for the batteries), or to lose the use of a boat’s navigation lighting, boat horns or bilge pumps because of dead batteries is a situation to be avoided. Thus the importance of battery management.

The foundation of the entire 12 volt marine electrical system is the batteries – both for energy and grounding, which are equally important. For each, the battery cable is a pivotal link.

Because of the nature of DC power and the easy potential for current loss over distance, battery cables are constructed of thick heavy duty copper and highly insulated. This makes them not only bulky, but expensive.

Good marine electrical design will use the optimal thickness (gauge) of the cables to provide the most current, while attempting to limit the distance they run, as longer runs necessitate increasing the gauge. Typically the cables will be terminated with either battery lugs (for the battery connection) or ring terminals, or most commonly a combination of the two.

Battery cables are available from many sources, although several websites now offer completely custom battery cables. The flexibility of these configurations allows boaters to get precisely the length, color, gauge and end-fittings that their boat wiring project requires.

While batteries may sometimes be mounted on trays, they are more often stored and held in marine electrical battery boxes, which, besides keeping the battery in place, also protects it from exposure to outside elements like moisture while also containing the corrosive acids of the battery.

Battery boxes also make moving and transporting the battery safe and easy. Battery boxes normally include a box with molded handles, a lid, a strap to hold down the lid and mounting hardware.

Battery boxes are available from several marine manufacturers, although the most well-known are built by Attwood Marine.

Part of a livewell system, in which a fisherman keeps his catch alive, the aerator (or livewell) pump helps to “aerate” the water and put oxygen into it. This is most often done by re-circulating the water in the livewell through the pump and back to the well via a sprayer that agitates the water and induces oxygen. These are typically known as “recirc” pumps.

Another use for this pump can be as a “pickup”, where it draws in the outside water to fill the livewell or refresh it. The pumps come in a variety of pumping capacities and are powered by 12V DC.

Aerator pumps are manufactured by several well know companies, including Attwood Marine. The Attwood Tsunami Series features innovative engineering and compact design, that delivers high output from a small package.

Attwood aerator pumps are famous for using the most advanced material available, including the best quality bearings and state-of-the-art brushes, alloys and magnets.

They offer three high-efficiency aerator pumps that move water at output capacities of 500 gph, 800 gph and 1200 gph.

What’s solar power?

Solar energy is radiant energy which is produced by the sun. Every day the sun radiates, or sends out, an immense quantity of energy. The sun radiates more energy in a single second than people have used since the beginning of time!

The energy of the Sun derives from within the sun itself. Like other stars, the sun is a big ball of gases––mostly hydrogen and helium atoms.

The hydrogen atoms in the sun’s core combine to create helium and generate energy in a process called nuclear fusion.

During nuclear fusion, the sun’s extremely high pressure and temperature cause hydrogen atoms to come apart and their nuclei (the central cores of the atoms) to fuse or combine. Four hydrogen nuclei fuse to become one helium atom. But the helium atom contains less mass compared to four hydrogen atoms that fused. Some matter is lost during nuclear fusion. The lost matter is emitted into space as radiant energy.

It takes an incredible number of years for the energy in the sun’s core to make its way to the solar surface, and then just a little over eight minutes to travel the 93 million miles to earth. The solar energy travels to the earth at a speed of 186,000 miles per second, the velocity of light.

Only a small part of the power radiated by the sun into space strikes the earth, one part in two billion. Yet this volume of energy is enormous. Daily enough energy strikes the usa to provide the nation’s energy needs for one and a half years!

Where does all of this energy go?

About 15 percent of the sun’s energy that hits our planet is reflected back into space. Another 30 percent is used to evaporate water, which, lifted in to the atmosphere, produces rainfall. Solar energy is also absorbed by plants, the land, and the oceans. The remaining could be used to supply our energy needs.

Who invented solar energy ?

Folks have harnessed solar energy for centuries. Since the 7th century B.C., people used simple magnifying glasses to concentrate the light of the sun into beams so hot they’d cause wood to catch fire. More than a century ago in France, a scientist used heat from a solar collector to produce steam to drive a steam engine. In the beginning of this century, scientists and engineers began researching ways to use solar power in earnest. One important development was obviously a remarkably efficient solar boiler introduced by Charles Greeley Abbott, a united states astrophysicist, in 1936.

The solar water heater became popular at this time in Florida, California, and the Southwest. The industry started in the early 1920s and was in full swing just before The second world war. This growth lasted prior to the mid-1950s when low-cost gas took over as primary fuel for heating American homes.

People and world governments remained largely indifferent to the possibilities of solar technology prior to the oil shortages of the1970s. Today, people use solar technology to heat buildings and water and also to generate electricity.

How we use solar power today ?

Solar energy can be used in several different ways, of course. There’s two simple forms of solar power:

• Solar thermal energy collects the sun’s warmth through 1 of 2 means: in water or in an anti-freeze (glycol) mixture.
• Solar photovoltaic energy converts the sun’s radiation to usable electricity.

Here are the five most practical and popular methods solar energy can be used:

1. Small portable solar photovoltaic systems. We see these used everywhere, from calculators to solar garden products. Portable units can be used for everything from RV appliances while single panel systems can be used traffic signs and remote monitoring stations.
2. Solar pool heating. Running water in direct circulation systems through a solar collector is an extremely practical solution to heat water for your pool or spa.
3. Thermal glycol energy to heat water. In this method (indirect circulation), glycol is heated by natural sunlight and the heat is then transferred to water in a hot water tank. This process of collecting the sun’s energy is much more practical now than ever before. In areas as far north as Edmonton, Alberta, solar thermal to heat water is economically sound. It can pay for itself in three years or less.
4. Integrating solar photovoltaic energy into your home or office power. In many parts on the planet, solar photovoltaics is an economically feasible solution to supplement the power of your own home. In Japan, photovoltaics are competitive with other kinds of power. In america alone, new incentive programs make this form of solar energy ever more viable in many states. An increasingly popular and practical way of integrating solar energy into the power of your home or business is through the use of building integrated solar photovoltaics.
5. Large independent photovoltaic systems. For those who have enough sun power at your site, you might be able to go off grid. You may also integrate or hybridize your solar energy system with wind power or other kinds of alternative energy to stay ‘off the grid.’

How can Photovoltaic panels work ?

Silicon is mounted beneath non-reflective glass to produce photovoltaic panels. These panels collect photons from the sun, converting them into DC electrical energy. The power created then flows into an inverter. The inverter transforms the energy into basic voltage and AC electrical power.

Pv cells are prepared with particular materials called semiconductors such as silicon, which is presently the most generally used. When light hits the Photovoltaic cell, a particular share of it is absorbed inside the semiconductor material. This means that the energy of the absorbed light is given to the semiconductor.

The energy unfastens the electrons, permitting them to run freely. Solar cells also have one or more electric fields that act to compel electrons unfastened by light absorption to flow in a specific direction. This flow of electrons is a current, and by introducing metal links on the top and bottom of the -Photovoltaic cell, the current can be drawn to use it externally.

Do you know the benefits and drawbacks of solar power ?

Solar Pro Arguments

• Heating our homes with oil or propane or using electricity from power plants running with coal and oil is a cause of global warming and climate disruption. Solar power, on the other hand, is clean and environmentally-friendly.
• Solar hot-water heaters require little maintenance, and their initial investment could be recovered within a relatively limited time.
• Solar hot-water heaters can work in nearly every climate, even just in very cold ones. Simply choose the best system for your climate: drainback, thermosyphon, batch-ICS, etc.
• Maintenance costs of solar powered systems are minimal and also the warranties large.
• Financial incentives (USA, Canada, European states…) can reduce the cost of the initial investment in solar technologies. The U.S. government, for instance, offers tax credits for solar systems certified by by the SRCC (Solar Rating and Certification Corporation), which amount to 30 percent of the investment (2009-2016 period).

Solar Con Arguments

• The initial investment in Solar Hot water heaters or in Solar PV Electric Systems is higher than that required by conventional electric and gas heaters systems.
• The payback period of solar PV-electric systems is high, as well as those of solar space heating or solar cooling (only the solar hot water heating payback is short or relatively short).
• Solar water heating do not support a direct in conjunction with radiators (including baseboard ones).
• Some ac (solar space heating and the solar cooling systems) are expensive, and rather untested technologies: solar air conditioning isn’t, till now, a really economical option.
• The efficiency of solar powered systems is rather influenced by sunlight resources. It’s in colder climates, where heating or electricity needs are higher, that the efficiency is smaller.

About the Author – Barbara Young writes on RV solar panel kits in her personal hobby blog 12voltsolarpanels.net. Her efforts are centered on helping people save energy using solar power to reduce CO2 emissions and energy dependency.

What a VSR does

The VSR is installed between two batteries. Many people are surprised to learn that it is NOT connected to either the alternator or charger output wires! Its setup is much more clever.

• If either battery goes above 13.7 volts (due to either alternator or charger output), the VSR connects both batteries together. Both batteries are now charging – without the boater ever having to throw a switch.

• Alternately, when the system voltage drops back below 12.6 volts, i.e., no more charging, the relay opens and the batteries are separate. This means that both batteries now discharge independently.

How a VSR changes real world boating

Let’s say that a fishing boat has a two battery setup. As is often the case, one of the batteries is dedicated to an important job – starting the engine. The other battery is used for other operations, including trolling.

• As the fisherman runs the boat from hole to hole, the engine alternator elevates the voltage to the cranking battery above 13.7 volts. This triggers the VSR to automatically connect the starting battery and trolling battery together. Both are now charging.
• Upon reaching his destination, the boater kills the engine – and, the alternator output – and begins trolling. Because of the lowered voltage, the VSR now disconnects the batteries. Because he is now discharging only one battery, our fisherman is going to have starting power when he needs it later – no matter how long he uses the trolling motor and depletes that trolling battery.
• Once underway again, the alternator power causes the VSR to reconnect the batteries and begins replenishing the trolling battery.
• Back home, the fisherman powers up his onboard battery charger. This increased voltage causes the VSR to once again link the batteries. This means that even a single output battery charger would now be charging both batteries!
• Our fisherman has had a great day on the lake, getting to and from his fishing hole, trolled for hours without killing a battery and never once had to worry about the settings on a manual battery switch.

Alternator II

More charge needs either a bigger alternator, or better yet, a second alternator which adds significantly more potential to the boat than only increasing the amperage of the original alternator.

The math is easy. Imagine a typical diesel with a 55 amp alternator. If the alternator is removed and replaced with a 100 amp model, we gain 45 amps. If you add a second 130 amp alternator to the original 55 amp system, you instantly send a battery-boosting 185 amps into the electrical system.

Higher charging also increases the vessel’s safety margin. Single alternators may fail due to overwork – the constant heavy load to recharge the boat’s electrical demand takes its toll. This could lead to discharged batteries, with all electrical systems shut down. I’ve encountered many boaties who’ve spent an uncomfortable night in the shipping lanes alternating the last of the battery power between radar and navigation lights…

Many consider the decision to fit a second alternator a no-brainer. The only question is: how do you install one easily? This article discusses a technique to mount a second alternator on almost any inboard engine. And it’s worth noting that the process can be used to belt drive more than just an alternator – a hydraulic pump, dewatering bilge pump or anything else you might need to turn are also possibilities.

SIX STEPS TO ALTERNATOR II

1. Design and planning
2. Mounting a second front pulley
3. Making a base plate
4. Building a bracket from the base plate
5. Installing a belt tensioning device
6. Bolting in the alternator

DESIGN AND PLANNING
Start the design process by taking an alternator in hand and holding it next to the engine with the pulleys aligned.

There should be 12 possible positions: starboard low, starboard high, port low, port high, and above or below the drive pulley.

Face the alternator aft and you have six more possible locations – for a total of 12.

Hold the alternator in all 12 positions. Pick the best two or three positions and compare the possibilities. Choose a mounting position with the alternator as close to the engine as possible. Look for access, wire runs, mounting bolt holes in the engine and cooling air.

MOUNTING A SECOND PULLEY
We need to spin the second alternator from a second drive pulley at the front of the engine. Your engine may already have one, but usually you’ll have to add one, bolting it to the front of your existing engine pulley.

First, choose a pulley size. For a typical 30 to 75hp engine with maximum rpm of around 3600, a good drive pulley diameter is about 175mm.

I’ve experimented with larger pulleys (up to 230mm) but it’s not effective as most engines begin to hunt at low rpm. Conversely, if the pulley diameter is less than 150mm I often have to run the engine up to 1200rpm to get a good charge.

If in doubt, duplicating the original pulley size is usually a good bet.

There are two easy methods to fit a spare pulley to the front of an engine:

1. Have a machine shop make the new pulley; or,
2. Modify an existing pulley.

METHOD 1
A machine shop makes the new pulley, the simplest but most expensive option.

The machine shop will need the bolt pattern and centering ring measurements from the existing drive pulley on your engine. If you can take the measurements from the manual, the machine shop should have an easy job. If you have to take the measurements yourself, use digital calipers. Be sure to scrape away any old paint so your measurement is metal to metal.

Note: If the alternator is to produce more than 80amps, you should use a dual belt drive. You’re pushing the limit with a single belt – it will often slip, leaving gobs of black, sticky dust in your engineroom.

METHOD 2
Buy an “off-the-shelf” pulley at your local hardware store and have a machine shop make a new centering ring that fits your engine. You can even use an old car’s sheetmetal “stamped” pulley. The machine shop will combine the pulley onto a centering ring and you’re ready to install.

This option has the advantage of knowing the pulley face angles are going to be correct and smooth. It does not take much angle error, a nick or lathe marks left in the pulley face to make the belt begin to “dust”. Belt dusting is the major problem in building a dual alternator system. Twist, misalignment, rough surfaces, and drawing too much load all add to the amount of the belt dust. Commercial pulleys help solve this issue.

MAKING THE BASE PLATE
The base plate is a steel plate that gets bolted to the engine, and it becomes the base which holds the soon-to-be fabricated alternator bracket. The bracket is typically welded to the base plate.

Look for flat areas on the side of the engine block near where you want to mount your alternator. You want the plate to cover a minimum of three bolt holes – five or six is better.

Cut a piece of steel to cover the bolt holes. Using 6mm plate is the minimum – 8mm is better. Test fit the piece of steel over the area of the engine block. If it all fits and covers the bolt holes, you’re ready to start marking and drilling the holes.

Marking where the holes are to be drilled can be challenging, especially if the plate is in a difficult to reach location. Here’s an easy trick – it’s what I call the “sneak and tap” approach, and involves using a sharpened bolt screwed into each of the engine bolt holes (one at a time) to serve as a “reverse punch”.

Leave just enough bolt thread (the sharpened point) showing so you can use a pair of pliers to remove the bolt. Lay the base plate in the exact final location. Now for the tricky part – strike the steel plate with a single sharp blow from a hammer directly over the punch. Once marked you are ready to drill the hole.

Remove the bolt/punch and shift it to a new hole. Fasten the base plate (with a bolt through the newly-drilled hole) in position. Another sharp tap, remove the plate and drill the new hole. Repeat this process until all holes are drilled. This method is fast and easy and leaves no sloppy holes. If you make the base plate perfect, the rest of the job becomes much easier.

BUILDING A BRACKET
The bracket is the metal frame that holds the alternator, allowing it to pivot for tensioning the belt. I like to use a 50mm piece of 6mm flat bar. Cut two ears and weld them on the flat bar at a 90º angle (see photo).You should now have a base plate and bracket all made up. They may need to be connected with a strut (depending on the position of the alternator) to get the two pulleys in alignment. It’s usually the simplest to weld the plate, strut and bracket together.

ALIGNMENT
To find the correct alignment for the alternator, lay a wooden dowel rod in the drive pulley of the engine. Let the rod find its natural centre. You can now simply lift the rod up and down to show where an exact straight line to the slave pulley will fall. Reverse the procedure until the slave pulley is pointed directly at the drive pulley.

Remove all parts and tack the strut into position.

Replace and see if it all fits. If it does it’s time to weld it up and paint. Use this dowel rod method anytime you want an easy check of belt alignment.

MAKING A BELT-TENSIONER
Turnbuckle tension arms are an easy solution for making an alternator adjusting arm, and you only need simple tools – a hacksaw, welder and a drill. If you were making a conventional car-type tensioning arm, you’d have to cut an arc in the flat bar with an oxy-acetylene torch. Many boaties fit this turnbuckle swing arm to their existing alternator just to solve adjustment problems.

Begin with a half-inch or larger open barrel turnbuckle, and remove the studs from the barrel.

Cut the centre out of the barrel, leaving leavening 120 to 150mm of turnbuckle barrel.

Weld the barrel back together. Put the studs back in place and cut them to the length you worked out for the project at hand. Weld a flat plate to the end of each stud, drill a hole in the plates and mount to the engine.

STOP ENGINE BEFORE TURNING “OFF”
Ever notice what battery switches have printed on their faces? We all know not to disconnect the batteries while the engine is running, but what would happen if we did?

An alternator diode would fail – and that’s not good.

The reason is buried in Ohm’s Law which lays out the relationship between volts, amps, and watts. An alternator’s total power output is measured in watts. A typical high-output alternator might be charging 100amps at 14V – 100 x 14 = 1400 watts. If we had a 24-volt system, the alternator would be producing 50amps at 28 volts to make 1400 watts.

So, when we have an alternator producing 1400 watts and someone turns off the battery switch, the 1400 watts is already in the pipeline, so to speak. But the load (or current or amp draw) just dropped to zero because of disconnection to the battery.

Ohm’s Law tells us 1400 watts divided by zero (our new amp load) equals infinity. In other words, the voltage inside the alternator will climb toward infinity till it finds an escape route (the path of least resistance). That’s the shortest path to ground and typically, that’s the thin film inside a diode. Pop! The diode shorts.

Quickly switching the batteries back on might save the situation, but usually the damage is done. The boat owner may see the output of the alternator suddenly drop by a third. A typical complaint from boaties is: “My 100amp alternator is now producing 66 amps on the meter.”

This is because the alternator stator is really three-phase, and has three separate windings combining to produce 100amps. Since only the diode was ruined, each phase of the stator is still producing 33amps. If all three phases of the alternator are still producing 33amps each, why is the boat’s electrical meter only showing 66amps?

The “lost” 33amps are still being produced, but they’re not being rectified because that is the diode’s job. And un-rectified means alternating current (AC) is entering your DC system.

This is bad. At the same time that we are charging at 14 volts DC, we are also sending a battery-destroying AC “charge” into the boat’s electrical system. And because the boat’s electrical charge meter does not read AC, the owner has no clue something has gone wrong.

Those 33 AC amps are destroying the boat’s battery bank, electrical boards, and maybe even the hull zincs.

DIODE TEST
To check whether your alternator has a shorted diode you can clamp the positive alternator output lead with an AC/DC “clamp amp” meter. Switch the meter to DC amp and read the charge rate. Switch the meter to AC and we should see three or four amps.

A reading half of the DC charge rate indicates a bad diode. For example, if we were to see 66amps DC and 33amps AC, this would tell the technician it’s time to pull the alternator and change the diode pack.

Although not as accurate, we might also take a high-quality digital volt meter and measure voltage at the back of the alternator. We should see around 14 volts, but switch to AC and we should see around seven volts. Reading 14 volts AC could also indicate a faulty diode.

Adapted from Scott Fratcher’s How To Make Money With Boats, available at www.yachtwork.com

AUTO TENSIONING ARM
An automatic tensioning arm is another easy solution for a DIY installed alternator.

You can buy a “rasta” or LoveJoy arm for automatic belt tensioning from a good bearing supply house. Check out http://www.lovejoy-inc.com/

The device costs about $100. Simply mount the roller inside the unloaded belt between the drive pulley and alternator. In the photo above, the pulleys turn clockwise. Adjust the tension and ignore it for the life of the belt.

The second advantage of using a “rasta” or LoveJoy tensioning arm is the alternator does not have to rotate away from the engine to adjust the belt. This may mean a lot if you have a tight space to work in. You simply mount the alternator as close to the engine as you can manage and let the tensioning arm take up the belt slack.

AUTHOR PROFILE
Scott Fratcher has designed and installed more than 100 dual alternator systems. More photos can be found at www.yachtwork.com

Mr. Fratcher’s highly regarded books include

• How to Make Money with Boats
• Metal Boat Repair and Maintenance
• How to Buy Your Cruising Boat Now
• Earthrace – First Time Around

Mr. Fratcher also has an excellent website that is highly recommended to all easyacdc.com readers. Please be sure to visit Team Yachtwork and thank him for his thoughtful generosity.

The boat (Hammer P) is a 1966 -35 ft. OWENS flagship. She is double plank mahogany on oak frames, Teak decks and fiberglass cabin shell and fly bridge.

Equipment when we got her included mismatched and somewhat tired For V8 engines, Borg-Warner Velvet Drive transmissions all fresh water-cooled. Also outfitted with a 6.5 KW Kohler Gen- Set.

By mid 2006, I had decided that re-powering was essential. Having toyed with the electric idea for a year or so, I finally decided- "Just Do it" and began the search for a supplier for all the components. After considerable browsing catalogs and online information, this is what I chose for our application: (This is basic electric stuff)

2-Advanced DC Motors-L91-4003-13hp-72Volt

2-Curtis-PMC Motor Controllers- 72Volt-400amp

2-Merritt Inline Joystick control

2 -Albright Main Contactors

2 -Albright Reversing Contactors

3 -400 amp Ferraz/S'mut Safety Fuses

1-Link 10 E Meter

1-Onboard Charger 48-108 volt

2-Deltec Amp meter shunts

2-Westberg Ammeters

180 Lin. feet 2/0 Welding cable

90 Cable Lugs

24 -L16H Trojan Batteries

That is pretty much the electrics of the system, plus misc. hook up wire, etc.

The Mechanics portion needs some thought: Motor to shaft reduction, belt tensioner and battery placement. As you will see by the photos, I had to lengthen the propeller shaft to accommodate the larger pulley for a reduction ratio. I chose a 4:1 reduction because the motors need to turn fast enough to run cool and I need 1000rpm at the shaft to match our previous cruising speed. The rest of the mounting hardware is like a big erector set. All bolted parts were pre-drilled except for bolting to the original engine bunks. These were bolted in place after shaft augment. Motor mounts are adjustable for belt tension and tracking.

There are two flange bearings each side, and opposed for thrust bearings. This all makes a fairly compact package and we can now decide on battery placement. In our case, we are designing a 72 Volt system. Battery placement is somewhat a balancing act. Original components, (fuel) was stored behind the drive train and of course, motors amid ship. Fuel weight (160 gallons) was about 1300 lbs. Motors and transmissions about 1500 lbs. New battery pack weight: about 3000 lbs. To best balance the boat, I put 8 batteries forward and four behind each motor. With motors, batteries and electrical equipment we have an approximate weight gain of 1000 lbs.

Now, looking at performance. First we need to consider the boat Shape and Hull design. As the professionals see it, this is the second poorest hull design for electric power. Only a barge with square ends is worse. The ideal craft would have a sharp entry, a long waterline length and the transom out of the water. Boat design is always subject to compromise and the ideal form is not always practical. In our case, we will work with what is at hand and improvise, compromise and succeed.

Operation of the boat has not really changed. Still have twin props, still a hull speed just short of 6 knots (6.9 mph). What has changed is the planning and navigation. Without regenerative power we have to plan with power consumption. With batteries one should not run them totally dead. Always plan for about a 20% 'no touch' area to protect the battery life. In our case, we have about 670 usable amps that are available. Our "E' meter tells us exactly what power we have used and how long it will last based upon the rate of discharge over the last 10-12 minutes. It's nice to have that information available at the touch of a button.

For our longer distance cruises, we have adapted a temporary generator that run our battery charger at about 10 amps at best. Hi tech. chargers and modified sine wave generators are not very compatible for high output.Even the 10 amps will help some to increase longer distances. Over a 6-hour cruise, those 10 amps will return 60amps. Ifwe are traveling at 60 amps this has gained an extra hour of travel time. Of course now that we have made the trip, if it was one way, we need to allow adequate time to recharge. If we have used 550 amps and the charger output is 20 amps, potentially it could take 30-36 hours to recharge. Discharge rate and your speed are directly related and the need for speed shortens the trip. Here are some discharge rates that will help:

40-amp draw will run about 12.5 hrs.

60-amp draw will run about 8.5 hrs.

80-amp draw will run about 6.25 hrs.

Needless to say, the faster you attempt to travel, the shorter your travel time will be. This is where hull speed, weight and power storageneed to be considered.