Low visibility

psneeld said:

... The nominal range given in this Light List is the maximum distance a given light can be seen when the meteorological visibility is 10 nautical
miles. ...

Click to expand...

Sounds like they're referring to fixed navigational lights, such as lighthouses.

markpierce said:

Sounds like they're referring to fixed navigational lights, such as lighthouses.

Click to expand...

True but the same "light" theory may have bled over to their thinking about nav lights and their "nominal" range.

I don't care if you believe me...but 10NM is what I'd bet my rep on.

psneeld said:

I don't care if you believe me...but 10NM is what I'd bet my rep on.

Click to expand...

You're rare/precious, because I'm more likely to notice you before 99.9 percent of other boats/ships.

psneeld said:

Doesn't matter what you think...the definition of reduced visibility is less than 10 NM...so less than that lights and horn is required by the USCG.

Click to expand...

You might want to check on that. Bellingham Bay is about six or seven miles across. There are plenty of days when the haze or mist or rain is such that you cannot see Lummi Island on the far side of the bay from Bellingham although you can see boats out in the middle of the bay. But NOBODY including the big Foss and Crowley tractor tugs that are going out or coming in from tanker escort duty to the commercial fishing boats to the USCG vessels themselves coming and going from their Bellingham bases sounds fog signals. Don't know about running lights because in daylight it's almost impossible to tell if these lights are on anyway unless you're right next to the boat. The Washington State ferries don't sound their horns in conditions like these. The automated fog signals at various places in the islands don't come on in these conditions.

The ferry horns and automated signals don't crank up until the visibility is way low. Two, three miles maybe.

Marin said:

You might want to check on that. Bellingham Bay is about six or seven miles across. There are plenty of days when the haze or mist or rain is such that you cannot see Lummi Island on the far side of the bay from Bellingham. But NOBODY including the big Foss and Crowley tractor tugs that are going out or coming in from tanker escort duty to the commercial fishing boats to the USCG vessels themselves coming and going from their Bellingham bases has running lights on or sounds fog signals. The Washington State ferries don't sound their horns in conditions like these. The automated fog signals at various places in the islands don't come on in these conditions.

The ferries and automated signals don't crank up until the visibility is way low. Two, three miles maybe.

Click to expand...

That was pretty much the premise of my thinking too. "Restricted visibility" might actually have a local variation. Most of winter I can't see Texada or Hornby Islands from my house. ~4 NM away. Only when I can't see my neighbor, do I hear whistles.

Spy--- That's neat country you live in up there. I envy you your location and the great cruising waters you have within a fairly short reach. Where we can only dream about Desolation Sound and maybe get up there once a year it's someplace you can go on just a long weekend.

You're right. It's lovely.

Tonight: Rain at times heavy. Amount 30 to 40 mm. Wind southeast 30 to 50 km/h except 60 to 80 over exposed coastal sections before morning. Temperature steady near 7.

Northern Spy said:

You're right. It's lovely.

Tonight: Rain at times heavy. Amount 30 to 40 mm. Wind southeast 30 to 50 km/h except 60 to 80 over exposed coastal sections before morning. Temperature steady near 7.

Click to expand...

Well..... that's tonight. But today is just tomorrow's yesterday, right?

Pretty much, It's been a wet fall. Actually, I'm not even there right now anyways. If I'm here on the board, chances are I'm away at work that week, where the precipitation is whiter. Otherwise, on my weeks off, I am enjoying the beautiful area I live in (even with the relatively restricted visibility).

Northern Spy said:

Pretty much, It's been a wet fall. Actually, I'm not even there right now anyways. If I'm here on the board, chances are I'm away at work that week, where the precipitation is whiter. Otherwise, on my weeks off, I am enjoying the beautiful area I live in (even with the relatively restricted visibility).

Click to expand...

You got the best of both worlds there Spy!!

Elwin

Northern Spy said:

I learned it was 3 nautical miles, but don't think I have any documents to support it. If it were ten nautical miles I would (should) hear the ferries horns constantly in Oct-Dec and a smokey Aug.

Easy for me though as I have no professional reputation to defend. I did learn it when I was qualifying lookout however.

Darn it, now I have to look it up too!

Click to expand...

Hi All. Forgive me if I'm covering old ground, sounding pompous, or preaching to the converted...please!

In the IMO COLREGS (Wikipedia has the current version), restricted vis 'means any condition in which visibility is restricted by fog, mist, falling snow, heavy rainstorms, sandstorms or any other similar causes'.

Since the definition of fog is <1,000m (<5/8 stature mile) that's when restricted vis starts and the COLREGS are turned upside down with rule 19 coming into play - something few European boaters know or understand, and which has caused many an accident.

Out of interest, poor vis above 1,000m and caused by water droplets is called mist.

End of preach - back to breakfast....

Reading the expertise on the subject of low viability begs making an inquiry. Have any of you had an opportunity to experience what I call 'maritime vertigo'?

Allow me to explain: While tranversing a narrow channel under both total darkness with no shoreline / horizon visablility topped with deck level fog, 21/2-3 foot sea,15 kt wind radar and GPS on , mid way through the channel my indicator on the GPS took an abrupt Starboard position. As I was running at 5-6 knots and the channel being less than an 1/8 mile wide, fear struck as I pulled the throttle back

(Eric, the location is the channel behind Misery Island as you approach Meyers Chuck from Union Bay/Ernest Sound)

After stopping and slowly bringing the boat back to the correct heading and verified with the Radar, we began to move foreword again only to have the GPS indicator then take a hard Port position. I may mention that the wheel was being turned to counter act the apparent position.
Again we stopped and at this time I turned the GPS off and used the radar plus having one of the bodies on board strip off the bridge canvas and use the hand held searchlight to locate (because we were close enough to now see the cliff) land. We made it on and after securing for the night discussed what seemingly was a total loss of position in the sense one didn't know where one was!!
I might make note that I have traversed this channel during daylight with GPS on many times with the indicator acted normally.
I will add that the scope rotation on the GPS is somewhat slow as it is an older Lorance model.
Comments?

A.M. (al) Johnson-Ketchikan
Marben 27'

Al said:

Reading the expertise on the subject of low viability begs making an inquiry. Have any of you had an opportunity to experience what I call 'maritime vertigo'?

Click to expand...

Now that's really intertesting. Yes, both my wife and I have. Flat calm, no wind and pitch black. As dawn began (the sun would be rising straight ahead of us) it 'looked and felt' as though we were climbing a very steep hill - really wierd and disorienting.

greatpapabear said:

Now that's really intertesting. Yes, both my wife and I have. Flat calm, no wind and pitch black. As dawn began (the sun would be rising straight ahead of us) it 'looked and felt' as though we were climbing a very steep hill - really wierd and disorienting.

Click to expand...

During my mis-spent (what a long memory!) youth, I did a lot of Club motor sport, mostly rallying, usually over night. At times in fast twisting forested but relatively level areas,I thought we were going downhill,when not, and consequently reduced accelerator. After a while I recognized it,and kept the accelerator planted. But it was very odd. "Weird and disorienting" fit well.

Al said:

Reading the expertise on the subject of low viability begs making an inquiry. Have any of you had an opportunity to experience what I call 'maritime vertigo'?'

Click to expand...

Yes, once in our Arima fishing boat heading out at 4:00am for a company fishing derby in the late 1980s. Despite what our plotting Loran-C was showing us I was convinced it was screwed up and so put in the opposite steering correction to what was indicated. My wife finally convinced me I was wrong and headed for shore and the Loran was right.

Since you people are discussing weather, sort of, and it's you winter, hows this make you feel..? Cold is good maybe..?
Today here where we live, we touched 40C. 37C = 98.4F, so I'll let you do the maths. Praise the Lorrrd for aircon. at home, work, and in the car. However we don't have it in the boat, as the temps are not usually that bad out in the Bay. This is the highest December since 2001.

Peter B said:

Today here where we live, we touched 40C. 37C = 98.4F, so I'll let you do the maths.

Click to expand...

Better you than me. After almost 30 years in Hawaii if I never see the sun again and if the temperature never gets above 70 F it will be too soon for me.

Marin said:

Better you than me. After almost 30 years in Hawaii if I never see the sun again and if the temperature never gets above 70 F it will be too soon for me.

Click to expand...

...and there's my wife and I thinking 'it's really cold here in the UK, raining, extensive flooding across the country, no sun, summer passed by the UK this year - let's go somewhere like Hawaii'....

greatpapabear said:

...and there's my wife and I thinking 'it's really cold here in the UK, raining, extensive flooding across the country, no sun, summer passed by the UK this year - let's go somewhere like Hawaii'....

Click to expand...

If you want to go some place warm that's fine, but there are a bazillion warmer places on the planet far, far more interesting and worthwhile to go than Hawaii. Hawaii is a total waste of money in my opinion. Going to Hawaii is like buying a Fiat 500 instead of an Aston Martin. The Fiat may be cheaper but it's a case of getting what you pay for.

Just from the places I've been to that make Hawaii seem like the crappy LA suburb that it actually is are Malta, the Seychelles, Reunion Island, Dubai, Australia, New Zealand, Cyprus, Brazil, Chile, and Greece.

Again struggling to find the reference but I know it's tied to the NOAA definition and even NOAA doesn't have a separate glossary term "restricted visibility" but here's the back door to it also on the NOAA site..

CAVUClear or Scattered Clouds (visibility greater than 10 mi.)

The NavRules are for "not in sight" so that's as much of an issue than the "absolute" definition of when to light and sound....but for legal reasons the "anytime visibility is limited" usually gets grilled and the NOAA definition of "restricted visibility" comes up which is 10NM.

Marin said:

Better you than me. After almost 30 years in Hawaii if I never see the sun again and if the temperature never gets above 70 F it will be too soon for me.

Click to expand...

I hear ya. I spent time there as a kid and later in the Navy. I'm a fan of the wet myself.

psneeld said:

Again struggling to find the reference but I know it's tied to the NOAA definition and even NOAA doesn't have a separate glossary term "restricted visibility" but here's the back door to it also on the NOAA site..

CAVUClear or Scattered Clouds (visibility greater than 10 mi.)

The NavRules are for "not in sight" so that's as much of an issue than the "absolute" definition of when to light and sound....but for legal reasons the "anytime visibility is limited" usually gets grilled and the NOAA definition of "restricted visibility" comes up which is 10NM.

Click to expand...

Hi, I believe you'll find the NOAA rules are based on the IMO COLREGS (International Maritime Organisation regs for the prevention of collisions at sea). The definitions of restricted vis are very clear in that doc. I also believe you'll find the definition of fog is accepted worlwide as <1,000m.

BTW, from an eyeball height of 3m above sea level, the visible horizon is approx 4 miles, so to define restricted vis as 10 miles must surely be wrong!

I used to take the prevailing visibility readings at the control tower in San Diego years ago when I was an air traffic controller. When the visibility was less than 7 statute miles, we always had to include the restriction to visibility, i.e., fog, rain, blowing dust, snow (never used that one in San Diego, though). Visibilities above 7 statute miles was considered unrestricted and had no mention of limiting conditions.

I'm not sure if this relates to the discussion, but mine was a NOAA certification and they were NOAA standards that we as FAA controllers complied with.

Seems that the Colregs say sound horn or the correct device, in "Restricted visibility". Restricted visibility is than defined as any condition that restricts visibility, smoke, snow, fog etc. Distance does not seem to be defined.

Be interested to know the real requirements, and the rules that support it.

Colregs says: "Rule 19 - Conduct of Vessels in Restricted Visibility

(a) This Rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility. ..."

I don't find the above helpful in defining distance as it relates to limited visibility.

greatpapabear said:

...and there's my wife and I thinking 'it's really cold here in the UK, raining, extensive flooding across the country, no sun, summer passed by the UK this year - let's go somewhere like Hawaii'....

Click to expand...

We plan visiting UK next year,maybe June,wanting to see more than just London, to see the rural country, even get to Scotland. Is there any prediction which particular day summer will fall in 2013?
Sydney summer seems unusually variable this year, but a nice balance of some summer rain and mostly fine days.

Based on our experience with vacationing in the UK starting in 1990, including running narrowboats as well as hiring self-catering cottages all over Scotland, the Yorkshire Dales, the Lake District, and Cornwall, I would suggest spring is one of the best times of the year to visit. We have always gone in May, and it is wonderful. Not too hot, everything is green, it's lambing season so lots of activity in the Dales and Lakes, and even up in the Highlands (on both coasts) it can be very pleasant.

But..... school is still in session so you don't have to contend with the hoards of local vacationers in their cars and caravans cluttering up the roads and canals. The fall can be very nice, too, but if you wait too long, the days start getting short particularly up north.

markpierce said:

Colregs says: "Rule 19 - Conduct of Vessels in Restricted Visibility

(a) This Rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility. ..."

I don't find the above helpful in defining distance as it relates to limited visibility.

Click to expand...

Hi Mark,

COLREGS define restricted vis: "The term “restricted visibility” means any condition in which visibility is restricted by fog, mist, falling snow, heavy rainstorms, sandstorms or any other similar causes."

Rule 19 has the heading "Conduct of vessels in restricted visibility" and goes on to define the actions to take if vessels are not in sight of one another.

Because fog is mentioned I surfed the net and found nowhere that disagreed with the distance used in aviation of <1,000m. I checked over 20 other referenceds on the net, and the only distance shown was 1,000m (1 km)

A thought - I'll talk with the MCA this morning (The UK Coastguard and "COLREGS police") and check if they use the same definition. Could you do the same with the NOAA and we'll compare results.

Best - GPB

Well done guys for manfully, and repeatedly dragging the thread back on topic of poor visibility and issues related.

However Bruce, I agree with Marin, May is a great time to do the UK...

Sorry..back to visibility, which is good in the UK in May, by the way...

Regardless of the rules, if in doubt, why not just turn on the lights and sound the horn just for your own safety?