Update: April 6, 2003  0504 CDT

No pretty 3D images resulted from this week's effort ... just a LOT of research and number crunching involved.  A recent nautical periodical had a side-bar regarding alternative electrical generation devices utilizing Stirling-cycle engines.  One day of intense investigation convinced me that THIS was the optimum choice for SEDATION 4.  The specific unit, WhisperGen, comes from the Netherlands and is an amazing example of elegant engineering.

The WhisperGen, manufactured by Victron Energy, is a compact (17.7" W x 19.7" D x 25.6" H) and lightweight (198 lb.) unit which operates silently (44 dBa) and requires practically no maintenance.  This remarkable power plant produces 1600 Amp-Hours (Ah) of 12 volt electricity  plus 8 kilowatts (kW) of hot water using only 0.2 gallons of diesel fuel per hour!  A sophisticated microprocessor controller senses demands for electricity and hot water and responds automatically.

My previous generator choice, the Fischer Panda AGTPM4/12, is considered state-of-the-art in its class.   Smaller (25.2" W x 15.5" D x  15"H)  and lighter (185 lb.)  with considerably more noise (68 dB) and fuel consumption, the internal combustion diesel engine produces "stinky" exhaust with soot and annoying vibration.  This was the primary reason I designed a sound-proof machinery room in the aft port hull.  Maintenance requires oil-changes every 200 hours of operation (messy!) and routine engine service.  Admittedly better than most diesel gen sets, it is still a noisy beast.

A comprehensive treatise on efficient power generation, "Electricity on Board",  is available at the Victron web site.  This is NOT light reading but VERY eye-opening for the technically inclined.  After several thorough readings, I decided to perform an energy-consumption analysis of the electrical systems aboard SEDATION 4.  Wow!!!  All those amenities suck a LOT of power.  The bottom line indicated that my projected energy demands were in excess of the output of the WhisperGen :(   Back to the drawing board ....

Seawater cooling of the many refrigeration compressors (2 refrigerators, a deep freeze, air conditioning and custom dual ice maker) involves numerous pumps in traditional multi-vendor  installations.  These suck power and require a variety of service/replacement parts in onboard inventory.  I remembered the quiet, low maintenance air conditioning cooling pumps aboard SEDATION were manufactured by March Pumps, so I researched their product line and found these wonderful devices:

Two 809 series pump models are appropriate for these applications.  The 809-BR-12 provides 5.5 gallons per minute (GPM) using only 1.5 amps (16 watts) while the 809-BR-HS-12  provides 7.5 GPM at 3.8A (48W) for more demanding applications.  These are magnetically-driven units so there's NO seals to wear out or leak.  If (when) service is required, the motors can be removed from the pump housings without disconnecting water lines!  Maintenance requires adding 4-5 drops of SAE 20 oil to the motors' oil cups every 6 months.  No seals to stock or replace, no impellers to wear out, no messy service ... no-brainer to select.  By combining coolant-supply functions, based on projected duty cycle, I was able to eliminate the need for 3 pumps.  This helped lower my total energy demands.

Supplying both fresh- and sea-water to the 2 showers, 4 sinks, 2 heads, washing machine and other usage points aboard also requires pumps.  My analysis of on-board water requirements served to verify sufficient capacity of the watermaker and provide design criteria for the plumbing systems.  These applications require higher pressures but, usually, lower flow rates than the aforementioned cooling applications.  The SHURflo "Aqua King" line of pumps is standard in the marine industry.  I've had them aboard SEDATION 2 and will attest to their reliability but they are NOISY and suck energy.  Servicing or rebuilding these 3-stage piston pumps is not a pleasant chore ... been there - done that.

Now SHURflo offers the Extreme series of centrifugal pumps.  These are less complicated, quieter and require less power.  They cost a little more, of course, but the benefits are justifiable.  I've selected the Smart Sensor 5.7 variable speed model for SEDATION 4.   Since the WhisperGen provides copious quantities of hot water, there will be hot water tanks for both fresh- and sea-water.  The pressure wash system will use hot seawater to enhance removing seagull guano and other nasties from the boat's exterior.  I've designed an anchor-wash system that automatically cleans the ropes and chains as the anchors are hauled-in by the electric windlasses. Having lots of hot water available is a real luxury.  Long, hot showers are nice too :)

With energy consumption now reduced to a manageable level, it's time to design the boat's electrical system.  The necessary house battery capacity, 1600 Ah, requires massive heavy batteries.  The high-current draw of 12V anchor winches, heads, stereo amplifiers and the SSB mandate large cables.  The 110VAC inverter also requires huge battery cables to meet the load demands of  household appliances like the espresso machine, washer/dryer,  trash compactor etc.  Copper wire is heavy!  This weeks' project is to optimize placement of electrical components for minimal wire-run length with emphasis on weight-distribution to enhance vessel's balance.  Several distribution panels, located closer to the loads, should help.