Don't Rely on Mast-Top Anchor Lights -- Bitter Experience

[RaymondR]

It is impossible for an electric light to be mistaken for a star. A light that doesn't "twinkle" could be a shore light, a ships light, a navigational light, or even one of a very few planets, but it can't be a star.

This may well be the case in San Francisco which used to be known as the smog capital of the world however, in very cold dry or hot dry climates with low humidity and away from city lights stars can be very bright and since the twinkle is a result of atmospheric fluctuations they often don't twinkle much either.

The term "inconsiderate" does not reflect my feelings whenever a near collision occurs, the language I might use to express my feelings on these occasions would be flattered to be called profane. Go with the "inconsiderate" mate.

[Viking Sailor]

Originally Posted by RaymondR

This may well be the case in San Francisco which used to be known as the smog capital of the world however, in very cold dry or hot dry climates with low humidity and away from city lights stars can be very bright and since the twinkle is a result of atmospheric fluctuations they often don't twinkle much either.

https://en.wikipedia.org/wiki/Twinkling

Originally Posted by Wikipedia

Stars twinkle because they are so far from Earth that they appear as point sources of light easily disturbed by Earth's atmospheric turbulence which acts like lenses and prisms diverting the light's path. Large astronomical objects closer to Earth, like the Moon and other planets, encompass many points in space and can be resolved as objects with observable diameters. With multiple observed points of light traversing the atmosphere, their light's deviations average out and the viewer perceives less variation in light coming from them

I have observed the night sky from Alaska to Cape Hope, all of the oceans while at sea, and never noted a star that didn't "twinkle". I have seen Venus so bright that it cast a shadow, and still the stars twinkled.

[Rustic Charm]

There's a lot of talk on here about 'stars twinkle' and lights that don't 'twinkle' can't be stars etc.

Stars twinkle because of atmospheric interference. In space they don't twinkle because there is no interference.

Here on earth, stars 'twinkle' more depending on where you are on the earth and the clarity of the atmosphere. So, a one answer response that stars 'twinkle' everywhere and therefore all boaters should see the 'twinkle' is not realistic.

In addition, man made lights 'twinkle'. How much they twinkle depends on interference, but they most certainly can and do twinkle. Some people like myself can see almost any light 'twinkling' to various degrees. Some people can even see lights in the room they are in 'twinkling' and if responsible school planners take this into consideration they will install lights that are more friendly to children that have this impact.

So, when someone posts that they can't tell the man made lights from stars, then others disputing this is just rudeness. You may have no problem in seeing the difference, but you can't deny what another person sees with their own eyes. Just a perspective that doesn't seem to be acknowledged.

[Jon Eisberg]

Don't believe it's been mentioned yet, but here's another increasingly common contributing factor to many cruiser's apparent inability to see or distinguish masthead anchor lights...

;-)

Or, deck level lights, for that matter...

[Training Wheels]

+1!


Sent from my iPhone using Cruisers Sailing Forum

[Viking Sailor]

Originally Posted by Rustic Charm

There's a lot of talk on here about 'stars twinkle' and lights that don't 'twinkle' can't be stars etc.

Stars twinkle because of atmospheric interference. In space they don't twinkle because there is no interference.

Here on earth, stars 'twinkle' more depending on where you are on the earth and the clarity of the atmosphere. So, a one answer response that stars 'twinkle' everywhere and therefore all boaters should see the 'twinkle' is not realistic.

In addition, man made lights 'twinkle'. How much they twinkle depends on interference, but they most certainly can and do twinkle. Some people like myself can see almost any light 'twinkling' to various degrees. Some people can even see lights in the room they are in 'twinkling' and if responsible school planners take this into consideration they will install lights that are more friendly to children that have this impact.

So, when someone posts that they can't tell the man made lights from stars, then others disputing this is just rudeness. You may have no problem in seeing the difference, but you can't deny what another person sees with their own eyes. Just a perspective that doesn't seem to be acknowledged.

So let see... You are saying that a person who can see an Alternating Current (AC) powered room light twinkle, can also see a Direct Current (DC) powered anchor light that is less then a mile away twinkle. Since it is the effect of AC on the room light that they are observing as twinkling - I think not.

I have not read anything here that would indicate that twinkling is the cause for thinking that an anchor light is a star. Instead, it seems to be the dimness of some anchor lights that cause people to mistake an anchor light for a star.

[El Pinguino]

The reason top of the mast mounted anchor lights are mistaken for stars is that they are up amongst the stars.
The reason top of the mast mounted anchor lights are mistaken for shore lights is that they are in amongst the shore lights.

I can't really see myself saying to the third mate...'check all the stars... look for the ones that aren't twinkling and then look in the almanac to see if it may be Mars'....

Top of the mast combo tricolour/anchor lights were brought to us by the same people that gave us mast top mounted strobes....

[Dockhead]

Originally Posted by Viking Sailor

. . .
The first rule of watch standing is don't run into anything. For night watch standing that includes don't run into anything that has a light attached to it. So, if you see a light that doesn't "twinkle" steer clear of it - literally!

Being exhausted is no excuse for running into someone or something. Don't just plow ahead into an anchorage when you are so tired that you have become a risk to yourself and others. Either stand off and get some rest, or get some help. It is just good seamanship!

Amen!

If I could amend the "First Rule of Watchkeeping", I would add:

". . . or which broadcasts AIS, or gives any kind of radar return . . . "

[Rustic Charm]

Originally Posted by Viking Sailor

So let see... You are saying that a person who can see an Alternating Current (AC) powered room light twinkle, can also see a Direct Current (DC) powered anchor light that is less then a mile away twinkle. Since it is the effect of AC on the room light that they are observing as twinkling - I think not.

I have not read anything here that would indicate that twinkling is the cause for thinking that an anchor light is a star. Instead, it seems to be the dimness of some anchor lights that cause people to mistake an anchor light for a star.

I don't recall saying any of that actually

nor did I say that 'twinkling' is the cause of thinking an anchor light is a star

What I am saying, is that a number of folk have commented that you can tell the difference between a star and a boats anchor lights because a star 'twinkles' and an anchor light doesn't. And I'm suggesting that's not always the case, it depends on the person, as to some people, like me, all lights in the distance 'twinkle'. And yes, I have no doubt that the dimness of some anchor lights also confuse people.

[Rustic Charm]

Originally Posted by Jon Eisberg

Don't believe it's been mentioned yet, but here's another increasingly common contributing factor to many cruiser's apparent inability to see or distinguish masthead anchor lights...

;-)

Or, deck level lights, for that matter...

yep, that outboard on the back with dingy on the davits is definitely a problem.

[Kenomac]

On thing that hasn't been mentioned on this thread, were you anchored in an established anchorage where a fisherman would normally expect someone to be anchored? Or... Were you anchored in a traffic area frequented by fishing boats? We always choose anchorages out of the traffic and in close in order to avoid your sort of problem.

[Dockhead]

Originally Posted by Kenomac

On thing that hasn't been mentioned on this thread, were you anchored in an established anchorage where a fisherman would normally expect someone to be anchored? Or... Were you anchored in a traffic area frequented by fishing boats? We always choose anchorages out of the traffic and in close in order to avoid your sort of problem.

It's a good question. Hard to answer in this case. The answer is probably "both". It's marked as an anchorage on the charts, and there were dozens of boats anchored there during the day. But I was alone at night -- this being out of season.

This is the Solent, so fishing boats go everywhere. Everywhere, including the "established anchorages", is an "area frequented by fishing boats".


For people who continue to be confused by the basic facts of the case: There were two fishing boats involved. One didn't see me, and got his gear tangled in my ground tackle. I untangled the gear, and he went on his merry way. The second fishing boat, came to see what the fuss was about, while I was on deck untangling, and brilliantly illuminated by deck lights. He -- according to his own account -- made a mistake with his gear lever, and t-boned me while he was distracted talking to the other fisherman, thinking mistakenly that he was out of gear.

A most unfortunate incident.

But tomorrow early I set off across the Solent to Cowes, and Lallows will start on the work in the morning. Thank God.

[Jim Cate]

This thread has prompted me to do a little informal research. We've been in a number of populous anchorages of late, some with lots of shore lights, some with fewer, some with none whatsoever. I've been observing the anchor lights displayed on neighboring boats, both from our yacht and from the dinghy.

In the case of little or no shore lights, there is no way that one could confuse an LED anchor light on the masthead with a star when at a distance where collision is a worry. There is a huge difference between the brightest planet and the anchor light at a range of say 200 metres or so, and that is plenty of room for evasive maneuvers, even at cruise speed. As the distance increases, the distinction becomes less, but even at a kilometer or so the LED is brighter than any celestial object lesser than the moon. And I found that at that 200 metre range, I did not need to "look up" to see a masthead light - it was readily visible when looking towards the horizon, attempting to pick out floating things.

Where there are shore lights at high enough elevations that the masthead light is superimposed in them from close distances (where evasion becomes difficult) there is indeed a chance of confusion and simply not noticing the anchor light. In these situations, even a boom-height light may well disappear in the mess. And that is where a light which illuminates the boat itself well enough to be seen becomes most useful. Good spreader or foredeck lights, usually already on board a cruising vessel, do well at this task, and one illuminating the cockpit area helps define the length of the boat.

I think that the above mentioned difficulty with cockpit enclosures and big biminis obscuring upward vision is a big issue... and not just with upward vision. Many of these structures just have too damn many blind spots for good watchkeeping. I don't know how folks live with them... I could not, despite their comfort giving qualities.

Please note that all my observations were of typical LED lights. The typical installed brightness of these devices is a lot better than the incandescent bulbs of earlier times. Here in New Caledonia nearly every boat seen at anchor now is using some form of LED anchor light. And FWIW, a much higher percentage of anchored boats are displaying anchor lights here than in Australia. This includes lots of local yachts as well as the transient cruisers.

None of the above will compensate for inattentive folks failing to keep decent watch...

Jim

[Dockhead]

Originally Posted by Jim Cate

This thread has prompted me to do a little informal research. We've been in a number of populous anchorages of late, some with lots of shore lights, some with fewer, some with none whatsoever. I've been observing the anchor lights displayed on neighboring boats, both from our yacht and from the dinghy.

In the case of little or no shore lights, there is no way that one could confuse an LED anchor light on the masthead with a star when at a distance where collision is a worry. There is a huge difference between the brightest planet and the anchor light at a range of say 200 metres or so, and that is plenty of room for evasive maneuvers, even at cruise speed. As the distance increases, the distinction becomes less, but even at a kilometer or so the LED is brighter than any celestial object lesser than the moon. And I found that at that 200 metre range, I did not need to "look up" to see a masthead light - it was readily visible when looking towards the horizon, attempting to pick out floating things.

Where there are shore lights at high enough elevations that the masthead light is superimposed in them from close distances (where evasion becomes difficult) there is indeed a chance of confusion and simply not noticing the anchor light. In these situations, even a boom-height light may well disappear in the mess. And that is where a light which illuminates the boat itself well enough to be seen becomes most useful. Good spreader or foredeck lights, usually already on board a cruising vessel, do well at this task, and one illuminating the cockpit area helps define the length of the boat.

I think that the above mentioned difficulty with cockpit enclosures and big biminis obscuring upward vision is a big issue... and not just with upward vision. Many of these structures just have too damn many blind spots for good watchkeeping. I don't know how folks live with them... I could not, despite their comfort giving qualities.

Please note that all my observations were of typical LED lights. The typical installed brightness of these devices is a lot better than the incandescent bulbs of earlier times. Here in New Caledonia nearly every boat seen at anchor now is using some form of LED anchor light. And FWIW, a much higher percentage of anchored boats are displaying anchor lights here than in Australia. This includes lots of local yachts as well as the transient cruisers.

None of the above will compensate for inattentive folks failing to keep decent watch...

Jim

My observations are consistent with this exactly.

In my opinion, it takes very poor watchkeeping to miss an anchor light, particularly a bright LED one.

And basic seamanship also requires you to take extra care while under way on a really dark night when you can't see anything which is not lit up. Especially electronic means.

Radar switched off, pitch dark night, not looking up, barreling along -- that's just really poor, in my book. Just about the first, and primary rule of managing a vessel under way is not to run into stuff. And to take all appropriate means to be sure that you don't.

But at the very same time -- and this is the way it works in so many situations not on land -- poor watchkeeping is a fact of life, and something we have to take account of. We are obligated to take account of it.

That means taking all reasonable means to make it really hard not to see you you, at anchor on a dark night. I will be taking much more care about this in future. I have hooked up my spreader lights -- bright LED lights which don't shine right down the forecabin hatch (unlike the deck light). They light up the boat very brightly. I'm using those for the moment while I shop for LED lanterns.

I have not given much thought to this because I spent the summer above 60 N where for most of the summer there was simply no darkness and this was simply not an issue. The anchor ball was much more important (and how many of us use those always? I do!). But now it's the dark time of year here, and overcast skies are not that rare either, so I will be doing a lot of anchoring on pitch black nights. I will be well lit up from now on.


I shudder when I think back on that case a few years ago on that California lake when a speedboat plowed into a drifting sailboat on a dark night, killing several people. Yikes. The drunken deputy sheriff (or whoever he was) didn't see even normal nav lights, much less a single anchor light. While motoring at high speed in the darkness. How to prevent something like that happening to you? I guess there's no guaranteed prevention.

[Dockhead]

The rest of the original story . . . in case anyone is interested in how it turned out.


My insurance company came through far above and beyond the call of duty, waiving my deductible and agreeing not to go after the fisherman. http://www.cruisersforum.com/forums/...os-155725.html

The fisherman, overwhelmed with relief, offered to spend a few days helping me work on the boat, as some kind of compensation, which I gratefully accepted.

Lallow's started on the work today and promise to have it finished in a couple of weeks. I'll be gone on business for a couple of weeks, coincidentally.

So in the end everything has turned out quite well for everyone. In great part thanks to the extraordinary actions of the insurance company.