Roger H Strube, MD




A successful (comfortable) cruiser understands and manages resources well.  One of the most important resources is the Ampere.  The cruiser does not live by Amps alone but they are right at the top of the list.  All other aspects of a cruiser’s “activities of daily living” are controlled, regulated and/or facilitated by “Amps”.  Proper collection, storage and frugal usage of Amps will make an extended cruise a pleasure and are absolutely essential for living aboard.  Nothing on a cruising or live aboard boat works without electrical power with the exception of a diesel motor or generator and even those need electrons to power their starters.  Extended cruising and living aboard is like living off the “Power Grid” with a chance to drown.

For design and planning purposes the place to start is usually to determine how much of what kind of “juice” you will be using and then work backward to determine your required input.  As Millennium Dragon is a real functioning vessel it may be easier to understand the system if we start at the input and follow the flow of electrons to their final use.  The Dragon uses 115 volt AC for some devices and 12 volt DC for most.  The AC supply has two sources, although only one is, technically, an external source.

AC 115 Volt 30+ Amp Supply for Extended Use

Shore Power


The first and only external AC source is simply SHORE POWER.  A heavy duty 30 amp marine electrical cord is connected to the inside of the port hull at the bow and the other end is plugged into an outlet at the dock.  The port hull electrical deck fitting is connected to a 30 amp power source switch.


AC 115 Volt 30+ Amp Supply for Extended Use

The Generator

MillDragEntecGenInstal 005s

The 30 Amp power source switch mentioned above selects between Shore Power (red handle up), disconnect (red handle center) and generator (red handle down).  This switch is directly connected to a GE outdoor plastic circuit breaker box mounted in the Port Head Medicine Cabinet.  The circuits are discussed in detail in the attached pages.


The GE plastic circuit breaker box in the starboard head medicine cabinet controls the remaining outlets including the one used for the Microwave on the counter near the stove/oven.  With shore power connected or the generator running power is simply passed through this starboard breaker box to these outlets.  When at anchor, the generator is used to power all 110 Volt AC devices. 


12 Volt DC 400 Amp Hour House Battery Bank

Charger & Solar Panels


The 12 Volt DC “House Battery” system has two main inputs and several minor inputs.  Four (4) Siemens 100/90 solar panels are mounted between the Bimini/Traveler and the Radar Arch.  While at anchor this system is the ONLY PASSIVE INPUT to the DC battery power storage system.  At the dock while using shore power small smart trickle chargers keep the Batteries topped off.  Each Volvo Penta MD22 S120 diesel motor has it’s own starting battery.  The port engine battery powers the port engine starter and the Lewmar #44 electric winch at the helm station (raise main & control traveler).  The starboard engine battery powers the starboard engine starter and the Lewmar #44 electric winch at the aft cross beam (roller furlers & dingy lift).  The engine alternators charge these batteries.  Secondary charging of engine starting batteries is done using “Smart Trickle Chargers” when at the dock using shore power.

Complete descriptions of these systems may be reviewed  by clicking on the appropriate tabs at the upper left of this page or by clicking on the following links below:

1.  AC 115 Volt 30 Amp Shore Power for Extended Use

2.  DC  12  Volt 400 Amp Hour House System

Still interested?  Need more information?  Contact me at:
Captain Roger Strube
2560 Rio Palermo Ct
Punta Gorda, FL 33950
Home:    941.639.6232
Cell:       941.661.4579


[Ocean Catamaran] [Cruising Log] [Your Desires, Your Budget] [Specifications] [Hull Design & Construction] [Sail Controls] [Sailing the Dragon] [Interior] [Steering] [Water] [Waste] [Electrical] [AC 115V 30Amp] [DC 12V System] [Heating Cooling] [Mechanical] [Electronics] [Dragon's Lair]