Conference unifix::sailing

    Why don't you consider solar panels ????
    
    Bob Thuet
    

Never fearing to be opinionated .....

First, I'd suggest a masthead tricolor light for sailing at night. Most 
units use a 25W (2A) bulb and are much more visible than the usual deck 
level lights. A tricolor will both reduce electrical consumption and 
increase your safety. 

Next, the amount of current you are using is really quite substantial
(even for a larger boat with an inboard engine), and I would suggest
finding some way to reduce that consumption. If you are 10 miles
offshore, you don't really need to have your loran on continuously. You
could turn your VHF on only when you see another boat. (If you don't see
them, then they probably don't see you.) 

While a small gasoline generator will certainly keep your batteries 
charged, do you really want to listen to a generator running many hours 
a day? The quiet of sailing is one of the joys of sailing (for us). 

How about (yes, all expensive):

  An outboard engine with an alternator?

  A third battery?

  Solar panels?

  A towed water-driven generator?

My guess is that a standard generator will not be terribly reliable in 
the marine environment. One other worry (besides the gasoline): I'd be 
reluctant to have 110VAC running around my boat at sea. Unless the 
wiring and grounds are done right and everything is kept dry, this could 
be quite dangerous. 

Assuming you use a 400W generator and a 110VAC battery charger and 
assuming an overall efficiency of 75%, you could expect a battery 
charging current of perhaps 25A. Since battery charging is less than 
100% efficient, you will have to run the generator at least 4 hours per 
day to keep your batteries charged. 

Sophisticated marine battery charging systems are capable of 100A of 
charging current. Much of what I have read about marine electrical 
systems would suggest that your battery capacity is marginal at best, 
even with an inboard engine for charging. 

You have an interesting problem. 

Alan

    Re: .1   Solar Panels
    
    The problem with solar panels is that they need light to operate, and
    my peak power drain is running through the night when solar panels
    would be fairly inefficient :^) 
    
    In addition solar panels for re-charging batteries during the day are
    no easy answer either. A 42 watt ARCO panel (at a cost of $369 at West
    Marine) only delivers 15-25 ampere hours/day or one third of my night
    time consumption. For this it consumes 42.5" x 13" of deck space or 4
    square feet. The write up in Practical Sailor called into question
    their durability/reliability. For topping off the batteries solar is
    probably a good idea, and maybe daytime operation. 
    
    On a boat outfitted for long distance cruising, I would have a wind
    vane, not an electrical based steering, and VHF would not be an
    issue, then my consumption during the night could be offset by the
    charging from the day.
    
    
    Re: .2
    
    Alan;
    
    Yep a tri-color would reduce the light draw from 2.7 amps to about 2
    amps for a saving of 7-8 ampere hours. It's a good idea but a lot of
    time when we run distance at night we have to resort to the iron jib.
    Under those circumstances we have to use the deck mounted running
    lights and a steaming light. Again not having generation on the
    motor, when we motor we are still a net consumer of power unlike
    the in-board engine case where you output would probably cover the
    power drain.
    
    As far as reducing the power drain, we could run with less, but the
    biggest offender, the Autohelm, still needs to be run for long periods
    with short crew (and a 1st mate who can't stay awake at night very
    well). VHF could be turned off, LORAN only used for spot checks,
    instruments turned off, Autohelm used sparingly which could probably
    result in a lower power drain. We've made the trip back from
    Provincetown to Newburyport during the day with only half a battery
    drained.
    
    The costs for an outboard with generator run about $1500 (new) and
    $1000 used.
    
    Third battery only increases our capacity but still doesn't give
    us generation capability. (We are probably adding a third battery
    anyway). 
    
    Solar panels as related above would cost about $750 and consume
    8 square feet of deck space to give me 30-50 ampere hours.

    The safety is probably not too bad. I would connect directly from the
    generator to the boat's electrical system, and the generator is fused
    with a GFCI. Of course one wouldn't use it in foul weather because that
    would be begging for a disaster. 
    
    The smallest generator they make is a 500 watt model, with little
    difference in price up to a 1 KW model since the engine sizes are are
    about the same. Figure about $300-$450. 
    
    As far as battery capacity we are using two 105 amp hour batteries
    (Group 29) which is bigger than the normal size (Group 26 - 85 amp hour
    battery that they usually build battery boxes for. The only thing we
    could do is go to the largest size of commercial batteries they have
    (Group 32 - 120 amp hour) or start wiring things in series.
    
    As far as the noise at night, I agree it is a pain and a detractor to
    the serenity of the night sail, sitting there watching the
    phosphoresence of the wake, but this great high tech gadgetry must
    be fed.
    
    /jim
    

    
    I've seen boats with shroud-mounted (or spreader mounted?  I didn't
    see it too close) windvane generators.  Does anyone have experience
    with or thoughts about these?
    

    Last year I bought a small Tenaka generator from Boat US.  This
    unit is tiny (about 14" x 6" x 6") and produces 20 amps 12VDC. 
    The motor looks and sound like a well muffled small chainsaw engine.
    The unit cost about $250.  It DOES NOT product 110VAC.  When I use
    it, I just hook it up to the charging circuit on the DC side of
    my consta-volt.
    
    I bought the unit because I often cruise off shore and was worried
    what would happen if my main engine bought the ranch on a passage.
    As my boat was working under sail and consequently leaking when
    worked hard (fixed now), I was concerned about having power for
    lights, instruments and pumps (mostly pumps).  The unit does certainly
    shatter the quiet of the night and does have to be set up on deck,
    however, it is not too noisy and is a nice saftey measure.  BTW,
    it burns only 4oz of 1:50 gasoline/oil mixture per hour.
    
    

    Jim,
    
    The ideal would be an outboard with generator built in, since then
    whenever you've got the motor on, you're charging.  (No way do you
    want to listen to the o/b AND a generator while heading across Mass
    Bay at night.)
    
    So, have you considered the amount you could sell your present o/b
    for against the cost of a used one w/generator?  It might only be
    a little more than the cost of a new generator (well, a few hundred
    dollars is a little to us nautical types), and could be a lot more
    useful depending on the usage of your boat and motor.
    
    Travis

    Don't know what you requirements are for engine size, but many times
    you will find something like this in the Want Advertiser magazine.
    There is a section in there on boat equiptment, and often times
    you can find someone that just want to get rid of their engine,
    or someone that bought a new one.  A couple of years ago I bought
    an Avon Dingy and Motor at about 20% of the price of a new one.
    If you give me your requirements, I'll look to see what is avail.
    
                                         Bob
                                         264-8376
    

    Have you checked into retrofitting your outboard with a high-amperage
    alternator?  I know for a fact that OMC has them available for
    outboards of 8 h.p. and up.  

    what about belting a generator off the main engine?  If it was setup
    so you can connect/disconnect it quickly you could use main engine
    for creating electricity or motion in dead air (not both). the
    alternators that come with the main engines take too long to charge
    the batteries. They are not designed to put a load on the engine.

    Due to other reasons, we ended up buying a new Evinrude Sailmaster
    9.9 with electric start and a generator.
    
    The interesting thing is that the generator only provides about 4 amps
    which again really isn't enough to recharge a battery (i.e. 50% of a
    105 amp hour battery @ 90% charging efficency would take 15 hours).
    So it looks like we may still think good thoughts about a generator.
    
    /jim

    
    fyi, our Yamaha 9.9 puts out 13 amps, if I remember correctly. 
    It is also a 4-stroke and very quiet, although substantially
    larger and heavier than some of the Evinrude models, in particular
    the 'Yachtman', which appears much smaller and lighter (or was
    that a Johnson?)
    
       -Jim-->
    

    
    	As a matter of curiosity;  What do tow behind generators typically
    cost ?   How does this compare to the alternatives on a dollars
    per watt basis ?

    	Reg