=> I was wondering about using one of those small DC power converters on a
=> small, 20', power boat. You know the type that comes in various watt
They work :)
They also suck battery power in devistatingly high amounts well beyond 
the item they are driving.  If you are running a laptop off of one, 
expect several hours from a normal Deep Cycle batt..  If you run anything 
over 300 watts, best leave the motor running, anything over 500 watts, 
best check the size of the alternator on your engine.
Most I/O's of the past several years have alt's much smaller then their 
auto counter parts for reasons unknown to me..  In my case, I have an old 
1978 Camaro in storage.  It comes with an 80 amp alternator.  My 1985 
Regal with 2 GM engined I/O's totals 70 amp between the 2! (35 amps each 
engine).. 
Wattage is roughly amps X volts in a DC enviroment, ie a 55 watt 
headlight buld uses about 4 1/4 amps at 12 volts DC.  
Expect an inverter to be pretty inificiant, maybe 50 to 70%?
Assuming 50%, a 500 watt inverter at full load is draining 1000 watts of 
DC battery power.  That hits about 80 amps of draw.  Assuming your boat 
even has a 90 amp alternator, you would require that engine to running 
and running at 2800 RPM or higher, just to keep up.  SInce most have 60 
amp or smaller, even at cruising speeds, you will steadly be loosing 
battery power.
Sorry for the complex answer, but I looked into a bigger inverter to 
allow me to run say a coffee machine on my little cruiser.  The fact that 
I would have to run both engines for about an hour to recharge from a 10 
min brew, not to mention the size of the battery required killed the 
idea..  On the other hand, I do have a little 50 watt job for a laptop 
that works great :)
Given the costs etc, I am seriously thinking about one of those little 
Honda or Yamaha 800 watt portable gennies, small, quiet, light and very 
portable, and big enough to brew a pot of coffee or run all but stoves 
and hair dryers etc.  Store it in the engine bilge then strap it to the 
swim platform once anchored at the destination and run it when required.
Those little ones are quieter sitting on the platform then many built ins 
are!  They are also quite a bit cheaper then even a little 350 watt 
inverter, at least here in Canada they are..
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 * Fidonet:  Greg Moore 1:2424/222
 * Internet: Greg.Moore@Sbbs.gryn.org
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