Batteries are the storage area for electrical energy for the vessel. The larger the storage the more efficiently you will be able make use of all methods of generation. The normal units for measuring you boat's capacity for storing electrical energy is amp-hours. A battery is usually rated with a 20 hour or a 8 hour capacity, with the 20 hour being the most common. A 20 hour capacity of 100 amp-hours means it can discharge continuously at 5 amps for 20 hours [5X20=100].
Our goal was 400 amp-hours. This meant we needed 4, 100 amp-hour batteries to meet this goal. That may not always be practical from a space point of view. We arrived at the 400 amp-hours by considering our daily electrical needs and multiplying by 4. The reason for this is a compromise between electrical energy requirements and battery conservation. If you discharge your batteries below 50% of their capacity you will shorten their life significantly. So, if we use 100 amp-hours per day a 400 amp-hour battery bank would only give us 2 days if we want to stay above the 50% level.
There are really 3 choices in batteries: inexpensive automotive/RV batteries, marine designed batteries; gel-cell batteries. We researched the advantages or all options. Gel-cell were eliminated for our purposes because of the special charging requirements and cost. After much deliberation we went with good quality, inexpensive 12 volt RV batteries for 3 reasons:
Care of Batteries:
This is an important issue for the boater. Here are a few suggestions for looking after your bateries so they will be there when you need them: [after all they are a part of your safety systems]
There are 3 ways to test your batteries
We use an "E-Meter" to measure the flow in and out of the house battery bank. This will tell us the number of "amp-hours" stored in the bank at any time. Over time it will pay for itself in battery conseration.
Alternators and regulators go together to provide power to charge your batteries when the engine is running. There are whole books on this subject. We upgraded from the standard 50 amp alternator that came with the engine to a 100 amp alternator with a "smart" regulator. The alternator size should be about 25% of the total battery capacity. Our target was 400 amp-hours therefore we needed about a 100 amp alternator.
The smart regulator provides a more efficient charging rate by holding the charge rate up at 14.3 volts longer than the less efficient automotive regulator. When the batteries are about 90% charged, it then drops the voltage to the "float charge" and keeps it there - about 13.2 volts. An automotive type regulator can lead to persistent undercharging in a sailboat and shorten battery life significantly.
We removed the 50 amp standard shore-power charging system and replaced it with a more powerful charger-inverter. This provided more efficient 110v charging as well as giving us 110v while underway from the 1500 watt inverter. We selected the Heart 1500.
Solar panels provide an battery charging method not dependent on the engine being able to start. They are essentially maintenance free but do demand some real-estate due to their size. We elected to install 2, 60 watt panels on the bimini allowing us to stay at anchor for a week without running the diesel. The cost of the panels will be offset by the lower engine running costs. The best for us was the Solarex with the pair giving us up to a 7 amp charge rate in full sun.
We elected to use the HAM radio as well as the VHF for communications. It has the following advantages:
Enchantment has an Icom 706MK II with an automatic tuner to tune the insulated backstay to the desired frequency. For email there is a Kantronics KAM'98 modem, which of course also does many other things. For weather fax we use "Weather Fax for Windows" from Coretex.
Enchantment has 2 GPS's, one as a backup, due to the importance of GPS to navigation and safety. The GPS is connected to a laptop computer running Nobeltec's "Visual Navigation Suite". This software is capable of handling all types of charts including vector, rastor and photo. In addition, it displays both tides and currents as an overlay on the charts.
Get a diesel!
The Aloha 34 has about 20 US gallon fuel capacity. We decided to try and double that to give us a greater range. After many mesurements and much head-scratching a "saddle tank" was purchased with a capacity of 18 US gallons. This was installed on a shelf, aft of the starboard quarter berth. Valves were added to enable the selection of either the original or new tank. The tanks are individually filtered to make allowances for cleaning up contaminated fuel.
Stainless steel is not recommended for diesel fuel tanks as it can corrode in a salt environment from within. The ideal material seems to be the "cross-linked" plastics.
A strap was installed to support galley slave whether cooking or cleaning up in heavy weather. It was simply an adjustable strap that could be connected across the open end of the "U" in the galley. The cook simply leans back into the strap allowing the use of both hands.
We installed a line from the pressurized water supply to pass through a carbon filter, through the fridge, to the countertop in the galley. The idea was to provided quality cold water to the crew without opening the fridge. "Brita water" on tap. This allowed us to mantain a higher level of chlorine in the tanks without having it in our drinking water.
To facilitate the raising of the anchor we added a manual windlass. Why manual? A couple of reasons; cost, size, lower maintenance. Since the roller for the anchor was a single and on the bow we also added a anchor platform or bowsprit made of stainless steel. The allowed us to move the anchors forward and keep the stocks off the deck. It also allowed us to place the windlass forward of the anchor locker and avoid cutting into the hatch cover.
The washdown pump was installed on a shelf under the vee-berth along with the macerator pump for the head [see photo]. The washdown pump provides easy access to sea water to facilitate anchor washing and deck rinsing. This required running a 12 guage power supply to the vee-berth to meet the necessary 15 amp rating. We found a construction rated extension cord met the needs at half the price of 12 guage wire. In the anchor locker we installed a 10' length of hose and a shutoff valve to aide in the delivery of the water. Great for water fights too!! Doubles as a firehose in emergencies.
Lazy Jacks are lines running from half way between the top spreaders and the mast head to the boom. They catch the main as it is lowered to help minimize the deck clutter and confusion when reducing sail.
They are easily installed as long as you don't mind climbing the mast.
We decided that jacklines - lines on to which you clip your life harness - were necessary but not all that frequently. We bought a flat anchorline on a reel and used it as jacklines as well. We installed "D" clips to the deck 5 feet from the stern and had a "D" built into our custom made sampson post at the bow. The flat web anchorline can be connected through these to make our jacklines. Note: the aft "D's" are mounted 5 feet from the stern to allow a person washed overboard to reach the ladder. At 6 knots not many could pull themselves up to the stern by their lifeharness line.
Not a pleasant subject, but in areas like the Bahamas where pumpouts are not available an alternative must be made to dispose of sewage. There are essentially 2 alternatives:
The first approach is less expensive; however, lacks the option of holding the sewage until underway in open waters or until the tide can help "flush" the sewage out of the anchorage. We liked the second alternative considering the stories of flushing heads on swimmer's "heads"!
In the photo the forward pump is the wash-dowm pump and the aft, larger one is the macerator. To the right you can see the "Y" valve alowwing the tank to be emptied by either the marina pump-out or the macerator pump.