Leave instruments always on or turn off when not in use?

[transmitterdan]

Originally Posted by Group9

A friend of mine on an Ageis cruiser told me about having to pick up dead seagulls off the deck that would be killed while flying across the field of their phased array radar when it was at full power. I wasn't sure if he was pulling my leg or not.

He was not.

[Hoodsail]

At anchor leave Garmin GPS on w/ anchor drag alarm set, uncertain power draw. GPS circuit includes garmin gnx wind pack which draws 0.28 mA, so those are on also. And anchor lite. House batteries are separate from starter battery so have that security regardless of draw. No radar, but adding AIS soon.

[Cadence]

Originally Posted by a64pilot

I think actually there are studies, several in fact on how far away a Radar is dangerous, but I can’t point to any, and in fact may not be able to interpret what they say anyway.
I’d go out on a limb and say if you live near a TV transmitter or a power line your likely receiving more RF than from a modern little Marine Radar.
Now a friend of years ago used to work on F-106’s in the New Jersey National Guard and he said the Radar in one of those was so powerful that if you turned it on, it would light up all the florescent lights in a building all the way across the airfield, and if you walked in front of it you would feel a warming sensation. Now that is power, and I’m sure very, very dangerous.
Spool forward a couple of decades and the Longbow Radar on the AH-64 is so low power it’s pretty much undetectable, Modern Radars are so incredibly sensitive compared to just a few years ago.
Modern Radars are so ultra sensitive that they can have extremely low output, and in particular the Simrad 4G Radars are ridiculously low output, less than a cell phone. If true, then your being irritated less from a 4G Radar on the boat next to you than you would be if they are making a telephone call.
Personally I don’t leave mine on, in fact it rarely operates truth be told, but not due to my fear of RF, just I don’t often need the thing.

You forgot the microwave oven. Even though it is shielded it is probably emitting more than a G4 radar.

[jmschmidt]

Not a close parallel perhaps but most electronics on big airplanes do not even have on/off switches. The only way to turn them off is to find the bus that powers them and open the breaker or down-power the whole airplane for safety like when undertaking major maintence. The purpose of this is to eliminate on/off cycling and to keep everything at an even temperature and to eliminate moisture and reduce corrosion.

We leave our desktop computers on 24/7 for the same reason. After years ours are pristine inside and we live 100 yards from the ocean in a humid climate.

Computers and TVs all have a sleep mode that is supposed to accomplish the same thing.

On a small boat I’d don’t know if there is much, if any, payback considering the climatic variables, battery draw, etc.

[Cadence]

Even the old 15mi, 1had, had a sleep mode. I'm guessing all it did was keep the magnetron warn. I can't see even leaving it sleeping at the dock.

[Dockhead]

Originally Posted by a64pilot

I think actually there are studies, several in fact on how far away a Radar is dangerous, but I can’t point to any, and in fact may not be able to interpret what they say anyway.
I’d go out on a limb and say if you live near a TV transmitter or a power line your likely receiving more RF than from a modern little Marine Radar.
Now a friend of years ago used to work on F-106’s in the New Jersey National Guard and he said the Radar in one of those was so powerful that if you turned it on, it would light up all the florescent lights in a building all the way across the airfield, and if you walked in front of it you would feel a warming sensation. Now that is power, and I’m sure very, very dangerous.
Spool forward a couple of decades and the Longbow Radar on the AH-64 is so low power it’s pretty much undetectable, Modern Radars are so incredibly sensitive compared to just a few years ago.
Modern Radars are so ultra sensitive that they can have extremely low output, and in particular the Simrad 4G Radars are ridiculously low output, less than a cell phone. If true, then your being irritated less from a 4G Radar on the boat next to you than you would be if they are making a telephone call.
Personally I don’t leave mine on, in fact it rarely operates truth be told, but not due to my fear of RF, just I don’t often need the thing.

Also it depends on where it is, doesn't it? My 4G radar is 10 meters (33 feet) above the waterline up the mast, like on a lot of sailboats. I doubt that it affects people even in the slightest.

[transmitterdan]

If you follow the instructions from the radar manufacturer it will result in a safe installation for 99.99% of cases. If your manufacturer says to turn it off when near other boats then do that. Otherwise there is no recognized safety problem. No recreational radar I know of poses a safety hazard to nearby boaters. That is unless they board your vessel and attempt to climb the mast where the radar is mounted. In such a case surely there will be liquor involved and you will not be liable for the consequences of their drunkenness.

[David M]

Originally Posted by a64pilot

Depends on distance from antenna and output.
My B&G has lower RF than a cell phone. However even a regular consumer marine Radar once you get even a few feet away the radiation diminishes rapidly.
Then you have to consider the power they draw, if it’s only a very small amount of power, your not going to have a significant radiation hazard, that takes power, lots of power.

The power of all electromagnetic radiation drops with the distance squared from the source. No, I would not put my nuts a half meter from the radar. 10 meters away? No problem. Irradiating the harbor? You get immensely more electromagnetic radiation by standing in the sun.

[a64pilot]

Originally Posted by Group9

A friend of mine on an Ageis cruiser told me about having to pick up dead seagulls off the deck that would be killed while flying across the field of their phased array radar when it was at full power. I wasn't sure if he was pulling my leg or not.

There is a huge Mother of a ground based Radar system on the Air Force Base in Valdosta Ga., it regularly has dead birds in front of it from what I’m told.
It’s inelegant, but huge amounts of power can burn through a jamming signal etc. the old F-106 Radar of course had a small diameter antenna that couldn’t be enlarged, the only real variable was power. Apparently it had the capability of using tremendous power, from my understanding it would draw down the big V8 powered start cart plugged into it

[Group9]

Originally Posted by a64pilot

There is a huge Mother of a ground based Radar system on the Air Force Base in Valdosta Ga., it regularly has dead birds in front of it from what I’m told.
It’s inelegant, but huge amounts of power can burn through a jamming signal etc. the old F-106 Radar of course had a small diameter antenna that couldn’t be enlarged, the only real variable was power. Apparently it had the capability of using tremendous power, from my understanding it would draw down the big V8 powered start cart plugged into it

As a former chopper jock you can relate to this. He also told me that it was a safety regulation that they depower the aft facing Aegis system radar array (theirs don't rotate, they are big flat fixed arrays) whenever a helicopter was landing or taking off and the helo pilots would also be quite insistent that it was definitely off before they would come in for landings. We were assistant Scoutmasters together so I heard a lot of campfire Aegis stories.

[travellerw]

Originally Posted by frankmulder217

Instruments off or on do not make any difference with regard to lightning strike. Lightning comes from the top down AND from the bottom up. The top down thing is done by the thunderstorm and we can do nothing about this. From the bottom up is the positive streamer. The object is reaching out to the lighting. read https://science.howstuffworks.com/na...lightning4.htm
or look at the beautiful youtube video

. Here you clearly see the streamer going up. Now you can certainly do something to NOT produce a positive streamer. First make sure your mast is connected properly with the water. Aluminium or steel boats is easy other boats need some work. Second make sure there are no pointy parts up there. Windex and VHF antennas and such need a round top. A sharp point increases the Voltage and is more likely to generate an upward streamer than a nicely rounded top. Oh yes DO NOT USE AN UMBRELLA DURING A THUNDERSTORM. With a rough machined tip you might hold a beautiful item to generate an upward streamer.

I'm not trying to start an argument... but what you posted pertains to land. Yes it still comes from top and bottom, but doesn't work the same as on land. The fact that you say "make sure your mast is connected to the water" is also completely anecdotal. There is ZERO data to back that up.

In fact... After our strike I spoke with insurance people and scientists to try and understand why we were struck (yes I asked about grounded masts, steel boats, aluminum boats, catamarans, ect). The one conclusive data was that catamaran are absolutely struck twice as often. After that, the conclusion I came to, no one really knows how lightening works on the water. This is the reason that NONE of the insurance companies require anything, they don't know what to require.

For me.. I turn off our instruments as I have a gut feeling it helps (like I said, zero data to back it up)

P.S. yes we had a round antenna and our mast was connected to the water. The lighting did indeed follow that path and ALL OTHER PATHS. As such, it destroyed EVERYTHING that was connected to the boat via a wire! Part of the energy exited out saildrive destroying the clutch on the way out!

[Exile]

Originally Posted by travellerw

The one conclusive data was that catamaran are absolutely struck twice as often. After that, the conclusion I came to, no one really knows how lightening works on the water. This is the reason that NONE of the insurance companies require anything, they don't know what to require.

This is where I'm at too, so all I've done is purchase some anti-static bags for hand held electronics which I can theoretically throw into some sort of 'Faraday cage.' Except I've read that neither the oven, microwave, nor ammo cans qualify due to inadequate metal-to-metal contact when closing -- or something like that. I've read that having all under-the-waterline metal like seacocks, tanks, etc. bonded together (mainly for electrolysis) is supposed to help dissipate the electrical energy from a strike, but also read that not having them bonded helps prevent the energy from spreading! Given the present state of (little) knowledge, it sounds like both the chances of getting hit and the consequences that follow are entirely random. (Not sure what the deal is with cats). I've personally never been hit, and have sailed through some intense summer lightening storms off the US e. coast with all electronics on but no direct strikes nor harm done. But that's just more anecdotal stuff.

[mikedefieslife]

I personally got tagged during a storm in Sicily last month. Funnily enough, I have a catamaran.

Driving rain, thunder and lightening.

I went out into the cockpit didn't even touch any metal, just moved a cushion and zap. Got a sharp short electrical shock. Not pleasant, but not overly painful.

My VHF was humming too. Was worried that perhaps either the boat got hit or a touchdown happened nearby and overwhelmed my electronics, but I guess not as everything continued to work just fine.

[Cadence]

Originally Posted by mikedefieslife

I personally got tagged during a storm in Sicily last month. Funnily enough, I have a catamaran.

Driving rain, thunder and lightening.

I went out into the cockpit didn't even touch any metal, just moved a cushion and zap. Got a sharp short electrical shock. Not pleasant, but not overly painful.

My VHF was humming too. Was worried that perhaps either the boat got hit or a touchdown happened nearby and overwhelmed my electronics, but I guess not as everything continued to work just fine.

My guess is your rigging is bonded and you only got a corona.

[Watermann]

FWIW, on the commercial vessels I sail on, the electronics are generally left on all the time regardless of being underway, at anchor etc. The radars are placed into standby when alongside or if someone needs to go aloft but are rarely turned off completely. The magnetrons have a finite life of course but other than that, we haven't had any problems with anything just failing due to "age" or wear.

The vessel I'm on now I've been working on since it was built in 2009 and outside of a cracked GPS antenna which allowed water in, none of the electronics have been replaced or needed servicing beyond things like antenna connections.

The GPS units, GMDSS suite, VHF radios, autopilot control head, AIS, ECDIS, meteo instruments etc, are on 24/7.