night vision?

[bikedaft]

hi, recently arrived at a tricky navigation point (islands/entrance to loch/rocks/cross currents) 2 hours before daylight as we had more help from tide than expected. it was a lot darker than i remember for a while, i had to get to about 50m from an island before i could see it. just went slowly and did lots of gps plots on the chart, but this meant going below, losing night vision in one eye etc.

but was wondering about the night vision scopes? some say they are only good up to eg 250m (probably enough) and do some magnify more than 8x etc? (ie too much for a moving boat!) and after reading the wiki about different generations i am even more confused.

anyone use them? usually there is some light, but no moon, rain, and low cloud meant v little light that night.

ok i could buy a chart plotter, but would (apparently) would not be accurate enough for some of the rockier west coast anchorages. i could goof about and wait for 2hours/daylight too, but wanted to get to bed!

thanks

 

[sarabande]

Generation 1 NV stuff costs around £100 and has limited range as you indicate.

Gen 3 is very much more expensive (10 - 20 times more £££ !) but doesn't suffer from 'flare' e.g. if you look by accident at a lighthouse of leading light, so much.

FLIR kit is better - that's the stuff from Raymarine's new owners which give those black and grey videos of covert ops in Iraq and 'Stan. But it comes at a huge price for the moment while they recover research costs.

if you want to keep night vision, use low levels of WHITE light - not red - and use a pirate's eye patch to cover one eye when below. Regaining full NV takes about 20 mins, depending on how your power of adaptation is - it decays with age and the number of carrots you eat !

Perhaps one should not be relying on GPS, and not approaching an unidentifiable blacked out entrance if at all possible ? The risks seem a little serious, but I don't know the full scenario.

 

[Dockhead]

I have a Russian night vision scope on board. It is old so I guess first generation, but I don't know whether their generations correspond to ours.

It is moderately useful in situations such as those you describe. Its range is certainly more than 250 metres -- its range in fact is unlimited since it transmits nothing; it merely amplifies ambient light. It magnifies like moderately strong binoculars.

Its main fault is that it is terribly subject to flare, so that we have to switch off navigation lights in order to avoid blinding it with flare from there. So it becomes useless when there are any kind of lights around, but on a starlit night it's pretty good.

 

[jimi]

firstly, if you are doing GPS plots then you might as well save some pain and use a plotter.
I use a handheld plotter so I don't have to go downstairs, and I can keep an eye on whats happening. I suspect areaaly big torch might be more useful than a nighscope?

 

[BrendanS]

but was wondering about the night vision scopes? some say they are only good up to eg 250m (probably enough) and do some magnify more than 8x etc? (ie too much for a moving boat!) and after reading the wiki about different generations i am even more confused.

anyone use them? usually there is some light, but no moon, rain, and low cloud meant v little light that night.

if you want to know about night vision scopes, do a search for posts on the subject by old forum poster Milltech. He knew his stuff, and wrote several illuminating (!) posts on the subject

 

[prv]

I suspect areaaly big torch might be more useful than a nighscope?

Problem with that is if there's the slightest amount of mist or haze in the air - fire up a bloody great light and all you'll get is backscatter. It's better if you can have someone in the bow with the light so that you in the cockpit are not looking down the beam, but I rarely have that luxury.

Pete

 

[Dockhead]

For pilotage on moonless nights, by far your most useful tool will be a plotter at the helm. Next after that would be radar, which is cheaper than a good NV scope and about 1000x more useful (works in fog, which is much more terrifying than darkness, much longer range, gives precise range and bearings, etc) Then a good spotlight, and only then, far down the list, a NV scope, in order of usefulness.

 

[bikedaft]

thanks for the replies.

yes i probably shouldn't have been there at that time, but have never experienced it to be so dark, there previously has always been enough light to get by. i thought i was te only one to "shut one eye" i'll have to buy an eye patch now to complete the picture!

i normally have a big 12v spotlight, but couldn't find it? have got another one now, still puzzled about where the old one went. bloody fairies nicked it.

have been wondering about a handheld plotter for a while, but not sure of its accuracy on various west coast charts that were surveyed a long time ago, and are still being adjusted for gps coordinates.

radar, maybe next year!

nvg and flare - not much of a problem up here as long as i turn off nav lights (tho i have a tricolour, which is more out of the way)

cheers!

 

[prv]

i thought i was te only one to "shut one eye"

Nope, I do it too, as taught in Cadets. It's still my right eye I close on the grounds that that's the one that has to see through a rifle sight

Pete

 

[25931]

thanks for the replies.

yes i probably shouldn't have been there at that time, but have never experienced it to be so dark, there previously has always been enough light to get by. i thought i was te only one to "shut one eye" i'll have to buy an eye patch now to complete the picture!

i normally have a big 12v spotlight, but couldn't find it? have got another one now, still puzzled about where the old one went. bloody fairies nicked it.

have been wondering about a handheld plotter for a while, but not sure of its accuracy on various west coast charts that were surveyed a long time ago, and are still being adjusted for gps coordinates.

radar, maybe next year!

nvg and flare - not much of a problem up here as long as i turn off nav lights (tho i have a tricolour, which is more out of the way)

cheers!

Perhaps you shouldn't invite fairies on board.

 

[noelex]

if you want to keep night vision, use low levels of WHITE light - not red -

Keep it dim, but please stay with red.

i normally have a big 12v spotlight, but couldn't find it? have got another one now, still puzzled about where the old one went. bloody fairies nicked it.

If you see the fairies tell them I want my wire cutters back.

 

[bikedaft]

the red white thing is intriguing me too, cos the gps display is low level white light and did not seem to affect my night vision, and the depth is red. maybe both were just a low enough light intensity?

 

[mick]

I don't know anything about night vision gear (I use a spotlight if necessary), but you're right to be concerned about GPS/chartplotter accuracy on the west coast. I don't know if you're familiar with Soay near Skye but my plotter tells me I'm on the land when I'm bang on the right line to take me over the deepest part of the bar at the entrance.

 

[AntarcticPilot]

I don't know anything about night vision gear (I use a spotlight if necessary), but you're right to be concerned about GPS/chartplotter accuracy on the west coast. I don't know if you're familiar with Soay near Skye but my plotter tells me I'm on the land when I'm bang on the right line to take me over the deepest part of the bar at the entrance.

Also, the charts are sometimes not detailed enough for some tricky passages.

 

[bikedaft]

indeed, i have plotted myself on land a few times up the west coast, most recently about 400m from where i was at dark o'clock, so was not too trusting of gps to more than 1-200m.

(entrance to loch sween)

quick google search on night vision would suggest that half the websites believe in red to preserve night vision, and the other half believe in low enough light intensity. the most memorable one said

"How can I tell if a light (other than red) is too bright to preserve my night adapted vision?

How can you tell how much light is too much for the rods? Easy! If you can see the color of the light, it's too bright for the rods and the cones are now doing the work. If you only detect it as "light" and you still see the world around you in shades of gray, the cones are shut down and the rods are doing the work." interesting, and a good point, probably.

http://www.flashlightreviews.com/qa/nightvision.htm

will dig about and see if i can find out more info, the armed forces must have done a lot of research on this stuff?

 

[Dockhead]

thanks for the replies.

yes i probably shouldn't have been there at that time, but have never experienced it to be so dark, there previously has always been enough light to get by. i thought i was te only one to "shut one eye" i'll have to buy an eye patch now to complete the picture!

i normally have a big 12v spotlight, but couldn't find it? have got another one now, still puzzled about where the old one went. bloody fairies nicked it.

have been wondering about a handheld plotter for a while, but not sure of its accuracy on various west coast charts that were surveyed a long time ago, and are still being adjusted for gps coordinates.

radar, maybe next year!

nvg and flare - not much of a problem up here as long as i turn off nav lights (tho i have a tricolour, which is more out of the way)

cheers!

I don't know about the West Coast, but on the South Coast, Normandy, Brittany, the electronic charts I use (C-Map) seem to be excellent. Have not met any uncharted rocks or noticed any error.

On the other hand, in the Sea of Cortez, on the Pacific Ocean side of Mexico, two years ago, my plotter told me I was two cables (!) inland once. I never trusted it in those waters after that.

But you need the plotter for orientation even if the cartography is less than perfect.

For exact range to obstacles when you can't see, nothing, but nothing beats radar. I wouldn't knock around at night without it, personally. Because radar gets better every five years, a lot of yachtsmen upgrade and sell off perfectly serviceable equipment for a fraction of the original cost. Especially in the U.S.; check Flea-Bay. I think you can get a serviceable used radar set for a few hundred quid if you work the Flea.

 

[Scotty_Tradewind]

was wondering about the night vision scopes?
anyone use them?

you may find they don't focus very well on the charts )