I think all of the analysis here misses three important nav light
issues:
1) Are all the lights working?
2) Are they running overvoltage and therefore underlife?
3) KISS

1) Most larger vessels (including Fintry and her sisters) have nav
light control boxes that allow you to turn on any combination you
want, bulb by bulb. Their magic is that they sound an alarm if any
light that is turned on isn't lit. This is fairly easy with a current
operated relay. The watchkeeper then switches the box to the other
light of that type (yes, two of everything) and logs the event. In
Fintry's current state the second light runs on a different power
supply (normal is 220VDC, emergency is 24VDC).

Ever been up the mast to replace the tricolor bulb at sea?

2) The life of an incandescent bulb varies as the inverse 12th power
of the voltage difference. Running at 14.5 volts, normal charging
voltage, a 12 volt bulb has a life expectancy only 10% of normal.
Rather than worrying about voltage drop in wires back to the cockpit
-- easy to cure with slightly bigger wire -- I'd spend time
automatically reducing voltage when the house bus is high (not hard --
a relay drops out at 13 volts and puts a diode or two in series with
the supply.)

3)KISS. I'm no Luddite -- we'll have all the bells and whistles on
the bridge, but for nav lights I'll stick to wires and switches,
albeit with a current operated relay in the middle. Even with best
practice wiring on Swee****er, we couldn't operate the LPG stove when
using the sideband, which triggered the gas alarm. And, even with
heavy filtration and shielding, we had trouble with one VHF radio
picking up SCR noise from the autopilot. I have no desire to have my
nav lights flickering as I key a mike.....

By no means would I want a panel that prevented my turning on any
combination that my little heart desired -- strange situations
sometimes require strange solutions. At the very least, if you
normally use a masthead tricolor, you'll want to turn on the lower
red, green, and stern lights, without the steaming light, if the
tricolor goes out.


Jim Woodward
www.mvfintry.com



"Zenny" wrote in message ...
Why not completely automate the system??

1. light/night sensor for tri color sailing activated via relay (on with no
power)power use = lights/sensor only
optional switch setup for no battery power use is as follows:
solar panel to energize relay off during day hours(you prob will have a
panel anyway)
under motor power ignition will switch relay

2. under motor power ignition switch activates tri color relay offpower use
= relay and lights
(under motor you are re-charging via alternator power use is no issue)

3. switch (which is also master light power disconnect) which turns on
anchor lights

I also have a "project boat" powerboat that I like to "trick out as well
and use a similar system on it, to date it has worked flawlessly

it does not have all your bells and whistles but it is rugged and
inexpensive
(maybe a combination of both...lol)

Rob Sacco



"Glenn Ashmore" wrote in message
...
You might remember my efforts to control the nav lights from the cockpit
without paying the voltage drop penalty of long wires. It started off
as a simple little idea using relays and wire loops over reed switches.
Weeelll... it has gotten a bit past that. Now it is a surface
mounted solid state, shielded, isolated, waterproofed and
microprocessored box about 3x3x6 that fits right at the mast base. It
can support up to 4 control stations, each with an LED field indicating
which lights are on, which are burned out and which are short circuited
or drawing more power than allowed.

Now I have a couple of questions:

I have to say it is a lot more rugged than I expected. First of all the
central unit and the control stations are totally waterproof. I ran a
station cable along side my antenna coax and transmitted at 150W on
various frequencies with no effect on the system. I zapped it with a
Tesla coil and it just reset, turning off all the lights but causing no
damage. Can anyone think of a valid torture test short of conjuring up
a lightning bolt?

I programmed the microprocessor to recognize and prevent conflicting
light patterns like steaming light on with sailing lights, anchor light
on while any light patterns indicating headway are on etc. Then I got
to thinking that it might not be a good idea to design a switch system
that was smarter than the operator. This leads me to several
programming options:
1) Dumb it down so that each button turns on a specific light without
considering navigation rules.
2) Leave it like it is with discreet buttons for each light and have the
logic prevent conflicting lights.
3) Make it smarter so that one button sets a pre-defined pattern for
sail/masthead, another sail/deck level, another steaming and lastly
anchoring.

There are advantages and short comings for each. The dumb version gives
full flexibility but the smartest one takes less thought.

I sure would like some different opinions.
--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com