Conference unifix::sailing

    I would suggest that for a knot meter you use a towed 
    instrument, for an echosounder you can buy one fron Seafarer 
    that sits inside the hull ie no hole.......you simply glass in 
    the sensor. Fitting VHF , Decca or Loran is also moderately 
    simple. To pay for someone to fit instruments can add 
    significently to the cost......
    
    Pete

    You don't have to buy a special brand to mount the depthsounder inside
    the hull. mine is in a pvc 6" "cleanout" that I got from the plumbing
    supply store, and is filled w/ mineral oil, and epoxied to the hull. 
    There is some theoretical loss of signal strength. I say theoretical, 
    because mins still reads 199' when appropriate, which is the maximum the 
    display can handle.
    
    Just be sure it is not a cored hull - solid fiberglass needed, and that
    its signal will not hit the winged keel.

    If cutting large holes in your bulkheads makes you squemish, consider a
    bracket mounted compass.  Some of the high class bulkhead types like
    Path's and Ritchies can be fitted with a mast mount bracket which fits
    under the gooseneck.  These have an advantage over normal bulkhead
    mounting in that they're equally readable on both tacks.  Figure on
    about $160+ to buy both the compass and bracket.  Installation is DIY.
    
    Cheaper yet are some models of Silva and Airguides which can only be
    bracket mounted.  These have smaller cards than the above and are most
    readable if mounted close to the user.  However, four screw holes will
    be required at the mounting site.   The Silva is around $70 and the
    Airguides can be had for as little as $15.  Despite the price, the
    Airguide works better than one would expect.  I have one in my car and
    it hasn't boiled off its fluid despite years of sun.  It's kept me from
    getting lost on more than one occasion.  Beware that bracket mounts are
    vulnerable to knees and elbows.  If it's mounted where it can be seen,
    it'll be in the way.  If mounted out of the way, no one can see it.
    
    The cheapest knot meter is the Knotstick.  A plastic tube with a spring
    loaded indicator fastened to a string with a small drogue on the end. 
    You fasten the tube to a stanchion and throw the drogue overboard to
    use it.  No power req'd.  There's also a hand held version. 
    
    For a few more dollars and some holes in the boat, you can intall a
    self powered analog readout knotmeter.  No battery needed, the impeller
    powers the dial.  This is under $100.
    
    There are bracket mounted depth sounders.  They still need a hole for
    the transducer but no bulkhead hole.  However, they're even more
    intrusive than a bracket mount compass and they really look inelegant.
    
    If the purpose of a handheld radio is to save money, I don't think
    that'll happen.  It's strange how they always seem to priced on a par
    with full sized units of comparable quality.  And no one has yet
    figured out how to cram 25 watts into a handheld.
    
    - gene

    
    	25 watts at 6v (already a big battery pack) is over 4 Amps, RMS,
    	assuming (HAH) 100% efficiency. Even if a battery existed that
    	could do such power, the unit would cook your palm.
    
    	One under-$100 unit I'd recommend is SR Mariner; self powered from
    	the paddle, `cept for lights. The company lent me their tool to cut
    	the transducer hole (yes, a little scary, but came out fine) and 
    	when I broke paddles (trailering without removing, cleaning without
    	removing sender) they had a replacement UPS'd out for less than 
    	an arm & a leg.
    
    	Seen `em for $90. I think it's model 100 or something. You can
    	mount a switch to change scales, if you want- I left it on the 
    	more sensitive scale. This way the boat went twice as fast!!!
    
    	PS, will that wing catch lobster pots? If it does, it sure won't
    	let go!
    
    	Lastly, try to get a Marine Exchange catalog- there's a pretty good
    	deal, I think, on the Contest (ex Plastimo) bulkhead compass. One
    	neat thing is that you can read it inside the boat (OK add 180�).
    	You need these instruments, right? So go ahead and cut that
    	bulkhead!
    
    	And have fun. Scott.

    Any validity to the rumor that SR Mariner is out of business ... even
    though their instruments are still available? If so, does this mean its
    a risky proposition buying something you can't get parts for?
    
    Bob

    If Mariner is going belly up, do what we do at work.  Do an EOL buy of
    the exiting inventory before the creditors get to it.  At these prices
    that's still cheaper than a Signet, Datamarine, or B&G.
    
    - gene

    Depending how fussy you are on the position of your depth sensor,
    you could get one of these "Tri-ducers".  It's a little gizmo that
    has your knotmeter paddle wheel and depth sounder in one package
    (the "Tri" includes a temperature sensor).
    
    With the water ballast on our Macgregor 26, we couldn't install
    normal thru-hull sensors, so I hung a Tri-ducer off the transom.
    Just 4 screws (no holes).  It's theoretical main problem is that
    it's a narrow beam (made for a power-boat), meaning it may get 
    inaccurate if your heeling significantly.  Beyond that, if it's on
    the centreline, it works great.  Note though: It's at the rear of the
    boat, so if there's a rock to hit, the keel finds out about it first!
    
    For an instrument, while it may be a bit expensive for your suggested
    budget, I recommend the B&G Focus.  I've had it for a couple of years
    now, and it's a great.
    
    	Bob Halsey

    I remember terrific anxiety when drilling for a knot log in my
    previous boat, Pearson 22.  It turns out to be pretty easy.
    
    First, make sure you get a drill bit (looks more like a round
    saw that fits in your drill) that is exactly the right size. 
    Then, get an old piece of wood, drill a hole, and fit the
    transducer to the hole....now you know you have the right
    drill.
    
    Then approach your hull, and drill away.  Use 5100 or other
    sealant.  Put a block of wood behind it on the inside.
    
    I did this, it never leaked.  It wasn't hard.
    
    Good luck.

    
    If you drill holes in the hull, make sure to have a device which will
    ensure that the hole is perpendicular to the hull surface.  Eyeballing
    it (at least with my eyes) is not advisable.  Assuming that the thru-
    hull is threaded on the inside, any deviation from perpendicular will
    create a non-flush joining of the nut with the hull or backing plate,
    and you'll have to do more work in the end.
    
    They sell drill guides that keep hand-held drills perpendicular to the
    work surface, and I think they're pretty inexpensive.
    
       /Jim
    

    I feel bad that you didn't get to buy a J/24. But how about this: you
    can buy the spare compass I pulled out of my J/24. I'll sell it cheap.
    
    Paul

    
    	re a few replies back: 5200 is mostly an ashesive. I'd suggest
    bedding compound, assuming the hole drilling went well, and the hole is
    strong & true. Else true the hole up with something strong like epoxy.
    Bedding compound is easier to use, and in the event of changing the
    mount, you won't need a Sawzall & strong drink.
    
    SR out of business? Hmmm too bad- did anybody check out the story?
    
    	Scott.

>>>  And no one has yet figured out how to cram 25 watts into a handheld.
    
One of the reasons may be the disincentive the law provides.  25 watts 
is the max allowed in an installed VHF unit, 6 in a portable.  (Another
example of this thinking occurs with cellular phones -- 3 watt limit
installed, .6 watts portable.) 

If 25 watt handhelds were authorized, someone would figure out a way to 
do it. 

J.

    In case anyone is interested:
    
    After calling around, I found West Marine, on average, to have the best
    prices.  Moreover, they delivered the instruments the next day, which I
    wasn't expecting.  I went with the SR Mariner knot meter for $99, a
    Ritchie Helmsman compass for $100, and a Standard Horizon DS for $239.
    Incidentally, the last West Marine catalog I had was from 1985 (from my
    old CAL days) and the prices decreased on the instruments and only went
    up marginally on the compass. Regarding the SR Mariner: its funny how
    you start looking at catalogs and start creeping up in features and in
    price .... when all you really wanted was something that ran on its own
    power and gave me a rough idea of speed.
    
    I ended up having Wilderness Marine in Amherst, NH. install the three
    instruments for about $100.  One of the advantages of the trailer is
    that you can bring the mountain to Mohammad, so to speak.  $100 is
    cheap compared to the anxiety of cutting through the hull and cabin
    bulkhead. Regarding Wilderness: they are like many marine stores that
    quote list price on all of the instruments.  For example, Wilderness
    quoted the Ritchie compass at $160, the SR Mariner KM at $165 and so
    on.  Right.
    
    Now for some questions:
    
    1.  Is it worth paying $39 for a life time warranty on the Standard
        DS or take my chances that the instrument won't fail.
    
    2.  Do 5-watt solar panels (@ $99) mounted on a cabin top (not necessarily
        the optimal location I know) work well enough to trickle charge a small
        boat's battery that would ordinarily only be used to occassionally
        run the KM and running lights/instrument lights at night?  Since
        the boat is on a mooring its not always possible to charge it from
        shore side power.  The boat's last owner let the battery run down
        then carted it off and charged it at home.  Since running a battery
        completely down is suppose to be bad on a battery, buying a second
        battery is about $60, and installing an alternator on the OB is
        more expensive than the $99 - I'm wondering what's best? 
    
        Also, how rugged are these things (specifically Seimens)?
    
    Thanks,
    
    Bob

re .13 and the 5 watt solar panel:

See Note 1514.63. I'd estimate that, on average over the summer, you'd
get about 2.3 amp-hrs per sunny day from a 5 watt solar panel. Allowing
for clouds, haze, etc, you might get about 10 amp-hrs per week. This
would certainly keep a fully charged battery fully charged, but whether
it would provide enough recharging to meet your needs would depend on
the details of your electrical consumption. 

Alan

RE:.14 by MSCSSE::BERENS "Alan Berens"

re .13 and the 5 watt solar panel:

> See Note 1514.63. I'd estimate that, on average over the summer, you'd
> get about 2.3 amp-hrs per sunny day from a 5 watt solar panel.

Nit:
I went through your calculations and came up with 2.97 A-h per sunny day.
Also,  the mast,  boom and what ever else might shade the panel will
reduce output.


> Allowing for clouds, haze, etc, you might get about 10 amp-hrs per week. 
> This would certainly keep a fully charged battery fully charged, 

A rule of thumb is that it takes about 1% of a battery's capacity per day 
to keep it charged.  Also,  you should never plan on using more than about
1/4 of the battery's capacity.  These two "rules" mean that you should use a 
battery about 120 times the Amp-hour capacity as the peak current output of 
solar cell(s) that charge them.  A 5 Watt solar panel should be used with
ABOUT a 40 A-h battery for a solar power system.  Need more battery?  Then 
you need more of a solar panel.  Have more of a battery,  but don't need it?  
Then you might be ok.  It might take all of the 5 Watt panel's output to keep 
a ~200 A-h battery(s) charged.


> but whether it would provide enough recharging to meet your needs would 
> depend on the details of your electrical consumption. 

So make a current budget.

Total Amp-hrs needed = Recharging current + lights + electronics 

	     = {Size of battery in Amp-hrs}*7/100 
	       + ({total watts of lights}/12.6V*{average on hours per week})
	       + ({electronic current draw}*{average on hours per week})

A 5 Watt panel would give about 5 A-h of user power weekly (100 A-h battery).


Phil

re .15:

more nits:

Which of my numbers did you use? If you use the estimate at the solstice 
(which is the maximum length of daylight) 2.97 amp-hrs per day is about 
right. I averaged the numbers for the solstice and equinox to provide a 
single estimate for the entire summer, which is about 2.3 amp-hrs per 
day.

>> A rule of thumb is that it takes about 1% of a battery's capacity per day 
>> to keep it charged.  

This self-discharge rate sounds way too high. I think (without having my 
reference materials handy) perhap the 1% number is the maximum or 
recommended trickle charge. 

>> Also,  you should never plan on using more than about
>> 1/4 of the battery's capacity.  

Most of the published stuff I've seen recommends discharging a battery 
about half its capacity. This assumes that the battery is then 
immediately recharged. Leaving a conventional wet battery partially 
discharged supposedly reduces its life considerably (and in fact seems 
to in my experience). 

Alan

    Last year, when I was facing major repairs to my outboard, (lower end 
    completely corroded), part of my decision to buy a new one was to get
    an alternator. On my new 5 h.p merc, I believe adding an alternator was
    $60-70 option. I also acquired a digital multimeter for $19 when radio
    Shack had them on sale, so I was able to keep very close tabs on what
    the battery was doing.
    
    Although the alternator output is only a few amps at full throttle, it
    did the job very nicely - fully recharging the battery each time
    wwe used the boat.
    
    Our demands were quite modest last year - some night sailing - lights
    and depth sounder, cabin lites on a few overnights, and for day sailing
    only the depth sounder.
    
    Before you write off an alternator as too expensive, recheck the
    details. For my outboard, all it is is a coil that sits near the
    magnets in the flywheel plus a bridge rectifier.
    
    Bill
    

    I have no idea of the output and have never tried to do the math, but I
    found a cheap way to keep the battery charged on my 23' Kittiwake.
    
    I bought a $25.00 automobile solar panel that was made to plug into a
    cigarette lighter and sit on the dash. I cut one lead and added a diode
    so I would not lose current at night, connected it to my battery and since
    it had suction cups with it, stuck it on one of my windows.
    
    It works amazingly well. We do most of our weekday evening sailing on
    this boat, running a stereo, knot meter and running lights. 
    Occasional use of interior lights also. I have a regular 12v automobile 
    battery in this boat and have not needed to recharge the battery 
    once since connecting this up. Your experience may vary.
    
    Our Alden 36 has a regular charging system on it. Because of the
    huge deep cycle batteries on it, I have not tried the same system.
    Our electrical consumption is much higher in this boat as we spend
    entire weekends on it in the Gulf of Mexico.
    
    Hope this helps.
    Robert

RE:.16 by MSCSSE::BERENS "Alan Berens"

> Which of my numbers did you use? 

I confess,  I used your bottom line number for the 44 Watt panel without
going through all your calculations.  It was the number for the solstice.


>> A rule of thumb is that it takes about 1% of a battery's capacity per day 
>> to keep it charged.  

It's a recommended "overcharge rate" for solar systems for best battery life.
I can't find the book,  it's probably in a box marked "dining room fine china"
(Thanks to RS).  BTW,  this would be only for small systems.  A large array
probably should have a regulator that scales the current down to a trickle
rate when the batteries are fully charged.


>> Also,  you should never plan on using more than about
>> 1/4 of the battery's capacity.  

> Most of the published stuff I've seen recommends discharging a battery 
> about half its capacity. This assumes that the battery is then 
> immediately recharged. 

Which it isn't in a solar system.  Also,  by designing with average numbers
for usage and recharge,  we might forget that few weeks are exactly average,
so we need some "statistical headroom".


Phil

    The 1%  per  day  self  discharge rate is for Ni-Cads, which don't
    hold  a charge well. That's why they're mainly used in applicatons
    like  tools  or  rechargeable  flashlights  where  they  sit  on a
    recharger all the time.

    Gel Cells    (and    presumably   stanard   lead-acid   batteries)
    self-discharge  at  a  much  slower  rate (10 or 20% per year if I
    remember correctly.)

    According to  the manufacturer of the small Gell Cells which I use
    for  my  bicycle  lights,  one should charge them at 7.2-7.4 Volts
    until  the  charge current drops down to a rate which would charge
    the  battery  in  a bit over 100 hours, and then charge at 6.8-6.9
    Volts.  (These values are for 6 Volt batteries.) This may be where
    the 1% rule of thumb comes from.

--David

    In reading the replies regarding solar cells, the math seems to support
    that a single 5 watt solar panel could be used to trickle charge my
    battery over the work week.  My overall demands for the battery,
    otherwise, are minimal.  Two questions remain:
    
    	1. How durable are these panels (meaning: if I mounted one on the
           seahood, how durable are these to getting stepped or jumped on?)?
    
    	2. Since some amount of discharge occurs at night, do I need a
           photo sensitive switch to turn the charging off during the night or
           cloudy days?  The switch cost about $60 which is close to the
           cost of the panel.
    
    Bob

re .21:
    
>>>    	1. How durable are these panels (meaning: if I mounted one on the
>>>        seahood, how durable are these to getting stepped or jumped on?)?

Solar panels, like humans, cats, etc, do not like to be stepped or 
jumped upon. They tend to stop working and sulk. Some panels (the very 
expensive ones) will take more physical abuse than others.
    
>>>    	2. Since some amount of discharge occurs at night, do I need a
>>>        photo sensitive switch to turn the charging off during the night or
>>>        cloudy days?  The switch cost about $60 which is close to the
>>>        cost of the panel.
    
Nope, all you need is a small series blocking diode (couple of dollars 
at Radio Shack). Many panels have one built in.

    re: .17 
    
    Without getting bogged down in analysis, the empirical evidence
    strongly suggest that a 5 watt solar panel and/or a small motor
    alternator will provide for the typical demands that have been
    outlined.  We relied on an outboard alternator (5 amp max) with
    a deep cycle battery for two years in a similar situation and never
    had inadequate power.  We also know several people that use the
    5 watt panels in small boat applications.  They seldom if ever have
    a power shortage.  I might note that they (and we) typically use
    a kerosene lantern for evening cabin lighting/heating and for the
    anchor light. 
    
    	Howard

    My knotmeter transducer has a very slightly bent pin (axle) 
    which causes the paddlewheel to occasionally grab, giving erratic
    readings.
    
    I called Datamarine for a new pin and (why am I not surprised?) found
    that I need a complete 'kit' @$15.00 plus tax & shipping. Since this
    seem like overkill for a part that I could fashion from a dozen sources
    (a paperclip comes to mind), I'm wondering:
    
    Are there any characteristics, such as magnetic, which should affect
    my choice of metal for this pin?
    
    John

    The pin would have to be stainless or monel to avoid electrolysis.
    Supposedly, your paddlewheel should also be painted with a tin-based
    paint, but just try to find some.

    > The pin would have to be stainless or monel to avoid electrolysis
    
    That was my first assumption too. But then I wondered whether it was
    more important that the pin not interfere with the magnetic field
    around the transducer, affecting accuracy of the knotmeter.
    
    Since the exterior of the paddlewheel and base are non-conductive
    (rubber or plastic) where's the path for current flow to induce
    electrolysis. From the same magnetic field I suppose.
    
    JR

    I don't know what sort of size paddle wheel you have but there is one
    European variety where the pin can be replaced with a slightly modified
    large watch strap pin....
    
    Pete

    
    	The watch strap pin has a spring inside... show me a pin that
    does'nt rust!!
    
    	Your fear of lost accuracy is a nonissue. The pin won't be moving,
    so the (hall effect) pickup or coil (magnetic) won't be affected.
    Recalibrate anyway, to ease your mind.
    
    	I'd worry about modifying the holes, or whatever mechanical changes
    may take place. This will narrow your choice of repair in the future.
    Now if you pick up a bunch of pins, cheap, right size, you're all set.
    
    	But (eek) if you bunge the whole sender unit, I bet you're looking
    at a couple hundred for replacement(just a guess).
    
    	Does the pin rotate with the paddle? I'd bet not, and on this case,
    I think you'll be successful copying it.
    
    	Let us know how it goes!
    
    	Scott_who's_snapped_a_wheel_in_his_time

    Here in the U.K. you can get solid watch pins for some watches. They
    are attached with small looseable nuts at each end. They were the ones
    I was refering to. However a new pin for a Wasp log is �3.5 not too
    bad really.
    
    Pete
    

    I suspect the pin used by the manufacturer is a stock part- probably a
    machinisits dowel pin. Very unlikely they would specify a part that had
    to be custom made for a simple pin.
    
    If you have a mike send me mail with the dimensions, Ill look thru my
    supplies for a pin.

    Thanks to Ron Ginger, master machinist and non_frozen_snot boat
    aficionado, I have replacement pins for my paddle wheel.
    
    Ron will have to fill us in on what he used, but I think the source
    was going to be a piece of brazing rod.
    
    Ah, the wonders of VAXnotes coming to the rescue again.... I saved $15
    bucks and all it took was an 850 mile round-trip to deliver the
    defective part......
    
    Thanks Ron.
    
    JR

    
    Yes, Johns part was simply a length of brazing rod, cut to size and
    de-burred.
    
    Im a dedicated 'fixer'. I never throw anything out that can be fixed,
    and always like the challenge of such repairs. With slight reservation,
    Ill offer here to make other such parts for SAILING readers when
    commercial parts cant be found. I have a rather complete machine shop
    at home- Im currently building a steam boat. 
    
    I have two rates scales for such projects- if I find it interesting or
    challenging, I work for free. If its dull/dirty or otherwise
    uninteresting I get about $50 per hour :-) 

    Ron's rates are rather generous. As an additional tip, I might suggest
    that it'll always be to your advantage not to admit that said part 'might'
    wind up on a boat which is derivative of petroleum. In my case,
    friendship prevailed. ;^)
    
    JR

    Re: .-1
    
    I look at it this way. Trees are a form of vegetation. Oil was created
    over a long period of time from vegetable origins. Polyester resin is
    made from oil. My GRP boat is really a wooden boat, then - just very
    mature wood!
    
    Ron - I need a couple of new shearpins for my outboard, and I just know
    you need a few more jobs like that to justify the new lathe!
    
    Can you give me a quote - preferably one that is printable?
    
    - Brian :-)

	In the process of commisioning a new (to me, though used otherwise)
boat, I've found what I believe is a problem with the solar charging system. 
The boat has an 11W solar panal mounted on the deck aft of the cockpit, with a
line going to ship ground, and another to the (single) 12V battery.  After one
(fairly cloudy) week, the battery was rather discharged from it's point a week
earlier.  After a second (sunnier) week, it was up slightly.  There is
measurable current coming from the solar panal when it's sunny.  If I cover the
solar panel, there's measurable current going from the battery to the solar
panel.  Because the multi-meter I was using was unfamiliar to me, I'm not
certain of the units, but the current going to the panel when dark was almost
half that coming from the panel in the sun.

	What I gather from this is that if my panel had a built-in blocking
diode, it no longer works.  There isn't a separate one shown on the wiring
diagram in the boat manual (the solar panel is a factory option), but the
diagram shows an ammeter on the solar feed that isn't present, so that may have
been intended to incorporate the blocking diode.  Obviously, this is something I
need to fix, and my question is to how.  Presumably, I want to add a blocking
diode on the solar feed to the battery, to keep the current from flowing back to
the solar panel in the dark?  Will that be sufficient?  What are the
specifications for the diode?

Thanks,
Mark

It sounds like you need a blocking diode -- not all solar panels have
them. An 11W panel will supply at most 1A, so all you need is a small
diode from Radio Shack. A Schottky diode (smallest voltage drop) is
preferable. Get one with a current rating of 2A or so to provide a
margin of safety. Note that adding a diode will reduce the amount of 
battery charging somewhat. The voltage drop across the diode is 0.5 to 
0.7V, which means that more sunlight will be needed to raise the output 
voltage of the solar panel to battery_voltage + voltage_drop_acoss_diode. 
It is also likely that your panel has a fairly low maximum output voltage
to prevent overcharging the battery (ie, it is called self-regulating or 
some such). 

An 11W panel won't do much more than keep your battery charged -- see 
this and the other notes on solar panels (eg, 1514 and 1554). Our two 
panels (75W total, enough to damage the batteries from overcharging
without a voltage regulator) aren't quite enough to supply our modest
needs when living aboard/cruising. 

Alan

Re: -.1

	Thanks, Alan.  I picked up a diode at Radio Shack, and installed it this
weekend.  The current drop going to the battery when it's sunny isn't noticable,
and the current flowing back to the solar panel when it's dark isn't, either.

Mark