Conference vicki::boats

    better make it high enough for your fine guests that are tall and
    don't need to be any balder than they already are .........
    
    

Based on my experience, I wouldn't bet that fiberglassing over the steel
(I assume not stainless) will prevent rust, even if you use good epoxy
resin. Even epoxy isn't perfectly waterproof, and eventually moisture
will migrate through the epoxy and cause rusting. Might take a few
years, though. Polyester resin certainly won't be satisfactory. 

There is a place (whose name doesn't immediately come to mind) in the
old Hingham shipyard that specializes in making stainless steel pulpits,
radar mounts, etc. They did a quite good job repairing a bow pulpit for
me. I'd suggest talking to them before you try to make something
yourself. 

I'd guess, by the way, that guy wires wouldn't be necessary. But you 
may need to reinforce the sides of the cuddy. The loads created 
bouncing around in a rough sea won't be small.

    Paul,
    
      I saw a radar pole advertised in Anchor Marines catalogue (I
    will check tonight for details). I think it is made of aluminum.
    What you want is something like an aluminim light pole.
    Steve Joyce has a simple pole set up on his Chris so you might
    want to talk to him.
    
    Bruce (who is anxiously awaiting the new grady's maiden voyage)

    What you really need is: a grade of aluminum known as 6061t6511,
    it is an architecural grade of aluminum, its round, and is seamless.
    
    It comes in a variety of diameters. its not cheap, but in the long
    run it is very inexpensive. you should have a aluminum platform
    at the top with at least 4 gussets welded from the base to the
    pole. guy wires will not do much good, suggest you use stainless
    rod, and at least 3, 120 deg. apart. i would consider bolting
    a bottom plate to your deck, and possibly using your center
    console for additional support. whatever you do, its best to 
    stay away from the wooden homemade supports you had in mind.
    
    if you take a shoddy approach to this, you may have a new hat
    when you least expect it.
    
    
    jim.

    	Thanks for the quick replies. They got me thinking about how
    I might screw this up. Maybe I better buy one.
    	I had talked to an outfit at the boat show and they wanted about
    $700 for a very basic unit in SS. I had seen a pedestal in the Boat US
    catalogue for $255. Its adjustable between 5 & 7' and is made for
    center consoles and walk around cuddies. Its made of aircraft aluminum
    and appears to have a deck plate and a bracket . The plate on top
    has no gussets but I guess if its designed for this application
    it should be good enough. At least if it failI'll get my money y
    back.
                                                       
    Re .1> Al you'll just have to duck. If I make it high enough for
    you I'll never get it under low bridges. :^)
    Thanks Again                                            
    Paul
                

    One thing nobody mentioned, make sure you GROUND the metal mast
    to the ground system of your craft.  The EMF (Electro Magnitic Field)
    around a radar antenna, even a low power weather one, will induce
    voltage into the mental mast.  Could give you QUITE a suprize when
    you hit a wave and grab the thing to keep from falling down.
    
    Ed (EX navy radar tech)

    Paul, I think you can make something up for less money than your
    looking at. I think the pole I made was around $30.00. I got all
    the alum. at a scrap yard. 
    If you would like to see my set-up, I'm only a few hours down rt
    95 from you. Or if you would like to take a chance, you can have 
    the pole I have, if/when if sell my boat, as long as the new owner
    doesn't want the radar. My new 25ft Pro-Line is due up here sometime
    in April.
    
    Steve

    Re .7>
    Steve,
    	Maybe I moved too fast. I ordered one from Boat US. My first
    thought was that I could fab something for under $50 but I got cold
    feet when I started wondering if steel would rust etc. I can't weld 
    Aluminum and I imagine the cost of stainless would be enough to
    make the store bought approach not that much more expensive. Soooo
    with my schedule loaded to 150% as usual I figured I'd take the
    plunge and save some time.
    	I really appreciate your offer and I'd like to see how you rigged
    yours. Maybe I can coordinate a trip down there in the near future.
    What type boat is it...walk around?...full cabin?...cc?
    
    Paul

    Its the 21ft Chris Craft Walk-around. I mounted the pole just to
    the left side of the cuddy door. I used a fairing block to mount
    the pole to the inside of the cuddy side. Two screws hold the base
    to the deck. The pole did cause some crazing of the gel-coat on
    some of the cabin corners. When trying to run I a good size chop,
    there is a lot of stress put on the antenna/pole.
    
    Steve

    Paul.
    You'll have to give us a product review of that new apelco of yours,
    I'm still thinking about the RAYNAV R-20 Not sure though.
    My head has been buzzing with ideas on mounting also, Radar arch
    alum tube style seems to be the answer. Gives a nice place to mount
    the floodlights and extra rod holders and antennas.
    
    Can't wait to launch "Rainbow Chaser"    
    
                                           Walt
    

    re .10>
    Walt,                    
    	If I had my druthers I'd go with an arch but they are very
    expensive. Maybe I'll add one after I get my Tuna this year. :^)
    	My pedestal has arrived. It looks adequate but my original
    design would be stronger. I'm sure it will save me a lot of time
    installing it so I'm still feeling good about it.
    	I'm also still confident that the Apelco will meet my needs.
    I am gathering info on RADAR and feel that for collision avoidance,
    which is what I'm interested in, it will suffice. I compared the
    specs of the Apelco with the Ratheon R-10 and they seem close enough.
    I think that the big question remains in the visual display.
    	I also looked at the R-10 and low end Furuno at the Portland Boat
    Show. The display on the Furuno looked a lot better. I don't know
    how the higher up models compare but you might want to consider
    the Furuno for you application.
    	I'll publish a report on the performance of both the RADAR and
    the pedestal in the near future.  
    	BTW - Good to have you back.
    Paul	

re radar and collision avoidance:

There is an interesting little book available titled "The Psychological 
Aspects of Sailing" (or something close). It includes much really
interesting information that is useful to anyone on the ocean. One
chapter talks about radar and the well-documented phenomenon of
radar-assisted collisions (eg, the sinking of the Andrea Doria). There
is a graph that shows, based on testing, that the probability of a 
radar operator noticing a target on the radar screen is considerably
less than 1, especially after looking at the screen for a while. The
conclusion I drew from this chapter is that radar is an aid to collision
avoidance, but no more, just as loran is an aid to navigation. 

    the boat i bought last july, came with radar. i read the owners
    manual, and spoke with several others who use radar all of the 
    time. i agree, after awhile it all looks the same, its difficult
    to follow targets, and handle the boat. the 2 gents i spsoke
    with gave me some helpful hints. 1. watch for targets that 
    might cause a collision. 2. watch for targets travelling in the
    same direction, and at the same speed. In buzzards bay it could
    be a tug in tow. they use a steel cable, and there have been
    several accidents. I'll try this approach this season,
    but i think it takes some procatice.
    
    
    jim.

	Well I finally got my boat in the water... I had to take two weeks
vacation to get the time to do it... I launched on July 4.
	The RADAR works fairly well. As expected, the display is not as sharp 
as the raster scan units but you can see what you need for collision avoidance.
	I went out in the fog today and managed to consistently pick up buoys, 
other boats and so forth within a mile of my location. I don't think the longer 
ranges are really that useful with this unit except for picking up land masses.
The radar can pick up the info but can't really display it effectively on the 
tiny screen. 
	My opinion so far is that the Apelco 9900 is a relatively inexpensive
way to get a servicable Radar. Many boaters may have a hard time justifying 
$2500 for a RADAR but at $659 its money well spent.
 	I also think that the 9910 should be a good unit for the money. It 
has three times the pixel density of the 9900 and for about $1100 I think it 
could provide that extra margin of security that wouldn't be there for some
boaters that can't justify the high cost rigs. 	
	BTW - the pedestal is fine too; no creaking, groaning or apparent 
motion. 

Paul     Who_is_glad_to_finally_be_in_the_water

    
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Note 780.0                    The APELCO AR16 radar                   No replies
BOSTON::DAGOSTINO                                    12 lines   9-JAN-1991 08:36
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    I saw a new radar out from Apleco called the AR16. It's a brand new
    unit with a CRT screen similar to the Raytheon R10.
    
    After speaking with an Apleco rep it seems it is the same unit as the
    R10 and lists about $2100.
    
    Has anyone heard about or seen the unit? I've read some previous notes
    about the Raytheon R10 and it seems to be a good unit.
    
    Thanks!
    
    Joe D.

    
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Note 804.0                                                            No replies
SMURF::AMATO "Joe Amato"                               1 line   8-MAR-1991 08:29
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    Does anybody have any experience with the furuno 1720 radar?
    

    Hey Joe, what do you want to know..../////?????
    
    JIm

    Hi Jim
    
    I'm looking at radar, and have been considering the 1720.  I was
    looking for actual user feedback.  Reliability, what's good, what's 
    bad, ease of usage, maintainability, wish list, etc.  Any feedback 
    on actual usage in rain, fog, at night.
    
    Joe 

    Folks:
    
    I've got my hands on a copy of the Maintenance/Operation/Installation
    Manual for the DECCA Super 050 RADAR.
    
    If anyone needs a copy of it, or information regarding the beast, get
    in touch with me.
    
    The thing is almost 20 years old BUT it gets the job done.
    
    I actually fixed the darn thing -- Another interesting story about the
    Scurvy Queen:
    
    I was in the market for a radar, so I went to my contacts in the local
    marine trade to see if there were any around at "fire-sale" prices.
    
    One person told me that he had a guy that owed him about $400 on an
    unpaid bill and wanted my guy to take a RADAR in trade.  Me thinks -- A
    match made in heaven!
    
    I contacted the guy -- He was in his mid 70s -- and arranged a meeting.
    
    It turned out that he also had a ton of accumulated boat stuff in
    addition to the radar.
    
    Fellow boaters in my office and I took most of his excess at reasonable
    prices.  He wanted $700 for the Radar -- I told him it was only worth
    $300 (If it worked). 
    
    He agreed to $300.  I gave him a $50.00 deposit and took the RADAR to
    an Electronic shop that fixed them to check it out.
    
    The electronic shop guy remembered the RADAR and the guy I bought it
    from -- Seems he installed the thing on the original owner's boat.  AND
    the guy owed this shop money too.
    
    $75.00 later, I was told that the thing didn't work and he "guestimated
    that it wold be a $500 repair. Definitely not a good deal! I got the
    guy to give me the schematics as part of his effort.
    
    I took back the Radar and called the owner telling him I was giving him
    the Radar back and wanted my $50.00.   He said to keep the RADAR.
    
    Wellllll, I did.  It took me two years to line up an Oscilloscope to
    use on the beast -- BUT-- Last night I found out what was wrong.  I put in a .49
    resistor, a $2.93 capacitor and I need a transformer (I know the
    Electronic shop has one) and now I have to get a price on that.
    
    Sooo now the Queen is going to get an eye and it only cost me less than
    $150 (Paid the Electronic shop $20.00 to "Consult") for a 12 mile radar
    that has a 2 1/2 foot enclosed antenna.  Not bad -- Trying to talk the
    Fleet Admiral into popping $1,500 to $2,000 for a modern eye was to
    tough a sell.
    
    Next project:  The Queen's Autopilot -- Sumthin's wrong -- Queen just
    goes in circles when I light the thing off.
    
    Dennis
    Electronic Shop guy to give a set of schematics, figuring I'

I recently became a radar user.  It is a Furuno - 16 mile version.
I'm told it is quite a powerful radiation source.  This makes sense to
me if it can detect objects 16 miles away where the returned signal
strength is proportional to the inverse of the square of the source
signal. 

I'm interested in infomation regarding any health concerns from being
in close proximity to the radome.  Of particular intaerest: what is the
beam width (i.e. how far below the radome does the transmission become
negligible?  how does the power of the signal compare to other
radiation sources (chest Xray, sunny day, microwave oven, police radar
unit)?  any special concerns for pregnant women (e.g. my wife)?  does
switching to standby mode completely stop the transmission? any
articles on this subject?

Thanks,
Paul

    The only warning my Furuno 16 mile radar ( I think model 1671) gave
    was not to look into the dome while its xmiting.  I think the
    angle of the beams is such that it will not be xmiting down
    into the boat anyway.
    
    Bruce

    Practical Sailor had a recent article on marine radars. They compared
    several Furuno and Raytheon units.  All had vertical beam widths of 25
    degrees.
    
    On commercial units where the power levels are 10 kilowatts and up
    there are health risks that ship's crews take into account when working
    around the antenna. 
    
    Regards,
    
    	Howard

    Re .20>
    	You should avoid the beam, particulary looking into it. I believe
    it can contribute to cataracts. You can calculate the coverage based on
    your beam width. That should be specified in the manual. (I thought the
    beamwidths were even tighter than what was mentioned in the previous
    note but I'll defer to the writer's figure of 25 deg)

    
    Width seem to be 4 degrees.  Height seems to be 25 degrees.
    So it looks like you ar both right!
    
    

    I see the ads for radar in marine catalogs.... i.e. 1000 watt radar, 
    3000 watt radar etc.  Where do you get all this power on the 'average'
    boat?
    
    Jeff

    re. .25
    
    I think you'll find this is peak power. The average power because of
    pulse width and duty cycle (rep. rate) is a lot less.
    
    Steve

Right, the peak power of the pulse (a few microseconds long) is in 
kilowatts. The average DC input power is a few amperes (like maybe 4 or 
5, which is still a lot if you are running off battery power and not an 
engine-driven alternator).