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Voyagers analyze their energy impact

Oct 3, 2008
Even though solar panels can’t provide for all the needs of a voyaging boat, a panel or two can make a difference in reducing your fuel budget.  (Photo: Dick deGrasse)

Even though solar panels can’t provide for all the needs of a voyaging boat, a panel or two can make a difference in reducing your fuel budget.  (Photo: Dick deGrasse)


To the editor: There is a great deal of talk these days about being environmentally green. Kathy and I have been voyaging for more than 25 years on the same boat. In the past we’ve lived full time on our 35-foot sailboat Endeavour. More recently, the two of us have lived aboard the boat six months of the year.

We provide for our own energy needs, we either make fresh water or carry it aboard; sewage is pumped into a holding tank then into a pump out boat and we recycle everything.

What troubles us is when land people blame voyagers for various environmental infractions when just the opposite is true: we are the most environmentally conscious people imaginable. We can attest to the fact that the vast majority of voyagers practice strict environmental conservation and are as green as possible.

Electric energy
Our total daily electric energy usage averages approximately 55 amp-hours without either heat or air conditioning. To be certain, there are a few days each winter when heat or air conditioning would make our boat more comfortable; thankfully, most times local breezes lessen the need. Voyagers who anchor out sometimes have diesel or propane space heaters; very few have electric air conditioning. Boats tied to marina slips are frequently shielded from local breezes and, as a result, resort to electric heat and air conditioning. Living on a marina boat is much less green and uses resources more closely approaching land dwellers.

We moor or anchor most of the time and have all the necessary modern conveniences except heat or air conditioning. Our daily 55 amp-hour usage is for refrigeration, laptop computer, SSB radio, stereo, lights and computer DVD viewing. Most voyagers we know use more electric energy than we do: about 100 amp-hours each day depending on the size of their refrigerator/freezer, watermaker, microwave oven, SSB radio usage, computer use and hours of TV and DVD viewing. Our daily use of 55 amp-hours is equivalent to 1,320 watts per day or 40,000 watt-hours (40 kilowatt hours — kwh) of electricity each month. One hundred amp-hours is equivalent to 2,400 watts per day or 72 kwh per month. An average house on shore uses between 200 to 300 kwh of electricity each month not including electric hot water heating. Even at 100 amp-hours per day the modern voyager uses about one-third of the electricity of homes on land.

Sources of energy
There are five sources of energy on voyaging boats: gasoline, diesel, propane, solar and wind.

Solar: Our 64-watt solar panel provides 15 to 20 amp-hours of electricity each day in southern waters. We plan to exchange our present panel for a 130-watt panel because the new higher output panel will fit in the same space as the 5-year-old, 64-watt panel and provide twice the electric energy.

Wind: Wind generation contribution to battery charging is always an unknown. Most days our wind generator’s daily energy contribution is less than 10 amp-hours unless the wind blows continuously over 15 knots. A few days each season our 400-watt Ampair wind generator will top off the batteries when the wind blows 15 knots or more for at least 24 hours.

Gasoline: Gasoline is used to power our 3.5-hp 4-cycle outboard motor and our 2,000-watt Honda generator. Since solar and wind systems can’t meet our daily electricity budget we rely on the gasoline generator. The Honda runs approximately one hour each day and produces 35 to 40 amp-hours via our Heart 1000-watt battery charger/inverter. We make at least three trips ashore each week in our 9-foot inflatable dinghy using the 3.5-hp outboard. The Honda uses about 0.5 gallons of gasoline each day to top off our 330-amp-hour battery bank. Occasionally, we use the Honda to power our vacuum cleaner, heat gun to strip varnish, and other applications we do not wish to run through the DC to AC inverter. The outboard and the Honda generator use about 20 gallons of gasoline each month.

Diesel: Diesel fuel is used to power our 30-hp inboard engine. We no longer use the diesel engine to charge house batteries even though we originally installed a 130-amp alternator for this purpose. The diesel engine is used exclusively to move the boat from place to place. We average 100 engine hours each winter. Before acquiring the Honda 2000 generator we averaged 300 engine hours each winter (mostly to charge batteries). Diesel fuel consumption, efficiency and charging rates and the Honda are about the same. The Honda is far more cost effective considering replacing or repairing it compared with repairing or replacing our 30-hp 3-cylinder inboard Westerbeke diesel. At a rate of 0.33 gallons per hour we consume about 30 gallons of diesel each winter. At $4.00 per gallon we spend about $120 each winter for diesel.

Propane: We have two aluminum 10-lb tanks located on the transom. On average a single tank will provide fuel for the two-burner Tasco stove and oven for five to six weeks. We typically use four tanks per winter. At $9 each filling we spend about $36 per winter for propane.

Our total energy costs for six months: $636.             

—Dick deGrasse is a USCG veteran and holds a USCG master license for power and sail. He and his wife Kathy live on the 34-foot sloop in southern waters in the winter and summer at their home on Islesboro, Maine.