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Old 17-08-2013, 11:11   #256
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Re: Keeping Watch at Night ?

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Originally Posted by noelex 77 View Post
Its great if you can set up your boat so you can still get basic information like depth, heading, STW, SOG waypoint information etc with no, or minimal effect on night vision.
Few boats achieve these basic goals.
The lighting and controls on the B&G Triton displays are amazing. They dim down to the point of needing to stare right at them closely to see, but they remain crisp and sharp in detail and you don't strain. "Night" mode on them isn't even necessary, but provides an even lower level of clear, easy visibility.

None of the other instruments we have ever had (or have now) are like this. Our Furuno NN3D chartplotter/radar is the worse - when illuminated so that night vision isn't harmed, it is completely unreadable, and when it is finally readable, it causes physical eye pain. The "night" mode on it consists of dark grey letters on black background with bright green/yellow ship icons, bright red course line, and all other markings barely distinguishable from the background.

Luckily, Furuno provides a very easy way to simply toggle the display on/off, so we leave it off most of the night.

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Old 17-08-2013, 11:14   #257
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Re: Keeping Watch at Night ?

All responsibility rests with my boat manager!
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Old 17-08-2013, 12:13   #258
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Re: Keeping Watch at Night ?

When reading Internet sources you need to bear in mind that yachts at night have very unique requirements that are not matched by other night vision tasks that present in the modern world.

Modern pilots get most of their information from complex colour coded instrument displays. Military personal use night vision equipment (which is in -compatible with red). Drivers illuminate the road with powerful headlights.

The references have a lot of shortcomings, but if read them with to visual conditions present in a yacht and you will find that they are mostly supportive of red illumination for our conditions. (I must admit I gave up with the third reference I don't think they even understand the difference between rods and cones
Here are a few quotes:

The key then is finding a hue that we can have at a high enough intensity that we can see the detail we need without activating our rods to the point were they obscure that detail. Most source say this should be nothing shorter than 650nm. Experimentation shows a L.E.D. with a peek around 700nm seems to work best (perceived as a deep red). Note that red may be fatiguing to the eyes.


Thus, although there is no question that maximum scotopic sensitivity can be shown to be better after adaptation to red than to
white light, and that this advantage increases as the adaptation level increases, these results show that after adaptation to low inteniity levels observers do not suffer losses of visibility when tested under conditions which are above threshold and with targets which have sorne appreciable spatial extent.

If you must see detail (reading a star chart, or instrument settings) and can lose peripheral vision (see note 1), then a very long wavelength red at a very low level. Red really only has an advantage at very low levels (were the night blind spot is very obvious).


If you have any doubts look at this graph. If you want to turn on a light and avoid bleaching out your scotopic vision (shown in blue) do you turn on a light of wavelength 650nm + (red) where your scotopic sensitivity is close to zero, or do you choose a light of shorter wavelength?
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Old 17-08-2013, 12:17   #259
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Re: Keeping Watch at Night ?

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Sailing is suppose to be relaxing, but with no sleep after a few days , I would get a bit cranky
Who says? Nice thought and can be true, for sure, but offshore, you serve the boat.

Not that there's anything wrong with that.
And, yes, it can be a bit grueling at times.

Buck up or stay in the bay!
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Old 17-08-2013, 12:23   #260
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Re: Keeping Watch at Night ?

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Originally Posted by colemj View Post
The lighting and controls on the B&G Triton displays are amazing. They dim down to the point of needing to stare right at them closely to see, but they remain crisp and sharp in detail and you don't strain. "Night" mode on them isn't even necessary, but provides an even lower level of clear, easy visibility.
I have not seen these displays yet, but I am looking forward to it.
One of the major problems of LCD displays is that they are very hard to dim. It sounds like they have solved this problem which is great to see.

Dim is the most important thing, but if its not red you are bleaching out some of your rod function even if the display is only just bright enough to read largish letters or numbers. The resulting level of dark adaption may be sufficient, but its important to understand if you read figures under white light you do not have your full dark adaptation till several mins later.

Do the displays covert to red when you select the night vision option?
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Old 17-08-2013, 13:36   #261
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That's a bit steep, but if it was communicated to the crew in standing orders ,I view that as a serious breach.

In my case I modify the standing orders depending on who I sail with. Newbies get explicit orders to wake me for course changes , sail changes and vessels approaching ( vessels on the horizons , would have me up all night in certain places )

Dave
Standing orders? Are you in the navy or sailing a recreational boat? Funny.
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Old 17-08-2013, 21:52   #262
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Re: Keeping Watch at Night ?

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Standing orders? Are you in the navy or sailing a recreational boat? Funny.
In mid ocean I like to sleep sometimes. The standing orders provide the crew with the conditions under which I should be awakened or notified.
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Old 17-08-2013, 21:56   #263
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Re: Keeping Watch at Night ?

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Originally Posted by noelex 77 View Post
I have not seen these displays yet, but I am looking forward to it.
One of the major problems of LCD displays is that they are very hard to dim. It sounds like they have solved this problem which is great to see.

Dim is the most important thing, but if its not red you are bleaching out some of your rod function even if the display is only just bright enough to read largish letters or numbers. The resulting level of dark adaption may be sufficient, but its important to understand if you read figures under white light you do not have your full dark adaptation till several mins later.

Do the displays covert to red when you select the night vision option?
The night vision modes on chartplotters vary among manufacturers. Some have a daylight, dusk, night mode. Some have a dimmer.

The instruments also need to be dimmed.
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Old 17-08-2013, 22:02   #264
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I just tell the captives if you think "should I wake the warden" then you better just wake him.
Writing is a good practice more for the warden then the inmates. I think the warden would get his stripes ripped off if he presented standing orders.
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Old 18-08-2013, 02:54   #265
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Re: Keeping Watch at Night ?

Funny, I was almost compared to a nazi by ssaying I would put anyone who fell asleep off the boat.

Think about that for a minute - a person on watch is a person you have entrusted with your , and the rest of the crews , lives and your boat.

And you don't think that abuse of that trust by falling asleep is a serious thing?

They all get told, that if they are getting drowsy and think they might fall asleep, wake either me or my wife.

There is no shame in getting drowsy and asking for help. Falling a sleep is a no go as far as I'm concerned.

Dave you laughed at my rule, but now you're noting that you have standing orders. well, mine "stay awake or wake someone up" is a standing order
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Old 18-08-2013, 03:07   #266
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If you fall asleep on watch, one consequence is that you have to hand steer the following night. I suffered that punishment once when I fell asleep on watch as a ten year old. Never happened again.

George on Czarny Diament was wrecked in the Red Sea due to a sleeper. Took them 60 days to cut a path thru the reef and get his steelie off. So, not only did he toss the autopilot, he also tossed the helmsman's chair. So after that his crew always hand steered, standing up and no one ever fell asleep again.

The beauty of sailing is the basic truth that actions (or lack thereof) have consequences.
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Old 18-08-2013, 03:15   #267
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Re: Keeping Watch at Night ?

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Sound is one of the senses that alerts us to developing problems on a boats.
Most sailors develop a keen ear for what are the normal sounds emitted by their boat. A change in sound warrants investigation. This is true whether motoring or sailing.

As a simple example just recently the gooseneck developed an odd noise.
An investigation showed a nyloc nut had come off the in boom furling mechanism.
Another example was a clang on deck that proved to be a bolt falling out of a batten pocket receiver.
Most sailors could tell many similar tales of faults that were picked up on sound alone.

This does not exclude all music, or talking books, but when playing these you need to weigh up the diminished response of your second most important sense when sailing. This is particularly the case when using headphones, especially with music that has fewer pauses than the spoken word.

Sailing is like driving a great sports car the sound part of the experience.

If they're blaring, I would agree with you. But playing them at a reasonable level, I think they would be an asset to overall alertness. They should never be used when communication with other crew is needed. But that's true everywhere, not just on a boat.

Talking books put me to sleep. Listening to classical music enhances the joy I have at sea. It reduces my "helm sleepiness" significantly. I never put on classical music if I want to sleep. It's deeply loved in my bones. Just shoot me now if I can't listen to classical music while sailing. YMMV. But having been through a LOT of engine trouble, I felt it in my feet and in the vibration of the bench, and saw it in the exhaust. Part of my visual watch was watching gauges and the exhaust. I can't imagine a better way to leave this planet than at the helm on a beautiful sail with lovely classical music playing.

There's tremendous variance in classical music between loud and soft, and except for riotous endings of the type you see in the 1812 Overture (cannon going off, church bells, etc.), the loud is not often sustained, and pauses are part of the music -- where there's absence of sound is as significant as where there is.

It would be a shame to miss whale songs. On the other hand, they range from 20 - 45 minutes long, and since I actively choose what I listen to, there are down times -- between movements, while choosing something new to iisten to. I doubt I would miss it, and if I heard whales, believe me, the IPOD would be down. I'd wake the rest of the crew up for that one.

It is precisely because music is so precious to me that I don't play the IPOD loudly. At 67 I don't have any hearing loss, and I'd like to keep it that way. I wonder how many kids who crank the volume up on those things are going to find that they have hearing losses at 40 or 50 instead of 70 or 80.
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Old 18-08-2013, 03:22   #268
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Re: Keeping Watch at Night ?

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Funny, I was almost compared to a nazi by ssaying I would put anyone who fell asleep off the boat.

Think about that for a minute - a person on watch is a person you have entrusted with your , and the rest of the crews , lives and your boat.
Keel hauling is more effective

Actually I do agree, with two or more crew there is no excuse for falling asleep.
If crew have reached the stage that they have inadvertently fallen asleep how many more times have they been so drowsy that they are not doing a very good job?
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Old 18-08-2013, 03:27   #269
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Re: Keeping Watch at Night ?

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The parallel to singlehanding and Russian roulette is absurd.

If you're along the Spanish coast, or any coast, you need to be paying attention constantly. If you're withing ~50 miles of a coast line things get very different, likewise if you're in a shipping path, or any other quasi-legitimate cause for increased collision risk.

Roughly one year ago today a crew of four people smashed their boat (and died) right up on a clearly charted island while standing watches off the coast of Southern California / Northern Mexico.

I singlehanded the same area quite happily before and after, because I know that when I'm slicing between ~10 miles of water between unlit islands and the shore that's no time for taking a nap. The accident investigation couldn't show much data, but what's imagined is that they plowed into an unlit (but charted) island because the watch stander lapsed in his navigation duties, didn't see anything on the horizon, and a few minutes later collided with jagged rocks at 7 knots.

Anecdotaly speaking the majority of singlehanders I've met doing offshore passages are often better sailors than many of the crew on "properly crewed" vessels.

To widdle this whole thing down to "singlehanders are less safe than fully crewed cruisers" would somehow suggest that there is clear empirical evidence to support that, which simply isn't the case.

For every singlehander on a beach you can point to, I'll point to another boat loaded with crew that did the exact same.

Absolutely agree with you there. In all sorts of ways coastal cruising is risky -- much more traffic, light from the shore confusing the markers (lighted buoys, for instance, or range markers), greater risk of running aground, difficulties reading the chart, and risk of falling asleep while all this is going on.

You can have a crew of two or three, but if you have two in the cockpit one may be sleepy and not alert, so everything is left to one person who may or may not have the skills to, say, keep your boat on course. You may discover the hard way, as a racer I know did, that one of your crew is a yahoo who will stray from the established course on a whim. Having more people on board may increase risks if that person can't be trusted to follow directions. You may not find this out until you're 500 miles off course and said yahoo didn't keep the log up to date. First time I attempted to sail to that Tortugas, that was my situation with one crew member. We had major engine trouble and had to turn back or I would have put him off in Venice with bus fare back home.
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Old 18-08-2013, 03:33   #270
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Re: Keeping Watch at Night ?

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That is why I don't follow that line. I go a good ways to one side or the other and let those with fancy, accurate equipment stick to "the line". It is safer outside the box.

Sure. Unless you're racing there's no reason to rigidly stick to the rhumb line. I think doing that is an influence from many years of driving, where if you stray from "the line," you're driving through corn fields in no time ...
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