Low visibility

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BruceK said:
...... If using the horn, as I think we should, at what intervals should it be used? Does anyone have an automatic facility for this so you don`t watch a clock or timer?
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Many of the higher end VHF radios have a "loud hailer" feature and an automatic horn feature for these situations.

I believe it's every two minutes but I'm not positive. If someone else doen't post it, I will look it up.
 
rwidman said:
Not to be picky, but if there is a judgement, the case is not dismised. ;)
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Being picky, the plaintiff would only be liable for a damages award if the defendant had cross claimed, but should usually be awarded costs which normally "follow the event"(decision) anyway.
I think the moral is, have your lights on in fog,even if you doubt they will be seen. They might be seen,fog has heavy and light patches, and it may help in Court to show you took reasonably available actions, like flicking a switch to "on". It can`t hurt,and it might help.
 
Ron is correct, the horn interval for fog is two minutes. We have a Standard Horizon intercom/ loud hailer that will do all sorts of pre-programmed horn sounds and yelps through the main hailer horn. Now the hailer horn is nowhere near as loud as our big dual-tone air horns, but when we're in fog we turn on the hailer's two minute fog cycle and every time it goes off the person at the helm hits the air horn button.

There are programmable control units that can be wired into a boat's horn circuitry. What we do is the poor man's, or in my case the cheap, lazy man's version.
 
BruceK said:
If using the horn, as I think we should, at what intervals should it be used? Does anyone have an automatic facility for this so you don`t watch a clock or timer?
Click to expand...

My Coot has one located between the searchlight control and the autopilot:

img_118265_0_77ea7782460a514c0920ab4a069ef1b7.jpg



http://www.kahlenberg.com/documents/M-511CControllerBrochure.pdf

There are both simpler/cheaper devices to operate the horn automatically.

One to two-minute intervals.
 
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I installed a Fogmate horn controller to sound my horn at the appropriate interval, which I believe is 2 minutes. It can be tailored to vessel type per COLREGS. Cost about $100, is easy to install and keeps the radio free for radioing.


TSX-FM012.JPG
 
We have had to run on instruments in extremely "can't see past the pulpit" heavy fog quite a few times. I am not worried about getting the horn timing exactly right. We've got both a radio/hailer and a pure hailer on board each with their own speakers and auto fog horn capability and I far prefer using the big air horns. Run slow and have a crew member (in our case THE crew member) at the bow looking and most importantly listening. Watch the radar closely and in narrow channels pretty much ignore the chart plotter. Use your VHF to announce your position and course especially if in a marked channel with turns like the ICW but even in the open ocean. When in doubt STOP THE BOAT until doubt has been removed. Sure I turn my running lights on. What can it hurt?

I really don't care about what might happen in court. I don't want to hit anything in the first place.
 
One prolonged, every 2 minutes or less for underway power vessels.

Just in from a 3.25 hour tow in the NJICW....50 foot visibility...:eek:

Striper fisherman out there at night, no radar...lost as all get out...making things worse was not only no lights on the marks but also all the buoys are out for the season. To make it really exciting, in many places the channel has shoaled so it's less than 50 feet wide. :facepalm:
 
This afternoon made a 2.5-hour run to exercise the engine. Besides one slow tug+barge, there was little traffic. A couple of anchored, open-top, outboard boats had fishermen aboard. They did not show up on radar. (Very calm waters today, but a strong ebb tide. Made good 4 knots in one direction, and over 10 in the opposite. Estimate the tug+barge were netting 2.5 knots over ground.)

img_118306_0_b1342bdc06e8aa55cd6beb5f3eb5478b.jpg


img_118306_1_36b629df1f40d5dd5c2816882c464e05.jpg
 
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BruceK said:
A couple of times I`ve been caught off the coast in sea fog which occasionally occurs in warm, not cold conditions, over here. I`d use lights, more in hope than expectation they`d help. When you use fog lights on your car, you aim them low so they shine up under the fog (well that`s what we did in car rally competition).
If using the horn, as I think we should, at what intervals should it be used? Does anyone have an automatic facility for this so you don`t watch a clock or timer?
Click to expand...

One prolonged blast (4 seconds) every 2 minutes. If you are stopped and making no way, it's 2 blasts every 2 mnutes with 2 seconds between them.

I used to use a Kahlenberg M485, but have recently upgraded to an M511C. Takes all the stress out of it.

GPB
 
Marin said:
Ron is correct, the horn interval for fog is two minutes. We have a Standard Horizon intercom/ loud hailer that will do all sorts of pre-programmed horn sounds and yelps through the main hailer horn. Now the hailer horn is nowhere near as loud as our big dual-tone air horns, but when we're in fog we turn on the hailer's two minute fog cycle and every time it goes off the person at the helm hits the air horn button.

There are programmable control units that can be wired into a boat's horn circuitry. What we do is the poor man's, or in my case the cheap, lazy man's version.
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Hi Marin - Just as long as another boat listening doesn't think there are two boats around....
 
greatpapabear said:
I used to use a Kahlenberg M485, but have recently upgraded to an M511C. Takes all the stress out of it.
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Yes, the M511C helps relieve my stress.
 
Apologies for the succession of posts....just got up and seen the amount of comments I've missed overnight (I'm UK).

Around the English Channel, there are many times when vis is restricted, mainly by thick radiation fog which can last many hours, and at times, days.

The routine we follow is simple nav lights on, horn auto sounder on, and one of us mans weapons (radar) full time. Max speed 8kts.

We leave the pilot house doors open to listen. We don't go to the front of the boat because our horns are loud and hurt if we are in front to them.

GPB
 
greatpapabear said:
We leave the pilot house doors open to listen. We don't go to the front of the boat because our horns are loud and hurt if we are in front to them.
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Same here. No one forward of the pilothouse when horns sound.
 
greatpapabear said:
Hi Marin - Just as long as another boat listening doesn't think there are two boats around....
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Being as how anyone inside a running powerboat's not going to hear the horns anyway it's sort of a moot ( or in this case mute) point.:)

And if by chance someone does hear the horns and thinks it's two boats, well, they'll be twice as vigilant. Which should mean that we only need to be half as vigilant, right?:)

So less work for us.
 
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Marin said:
Being as how anyone inside a running powerboat's not going to hear the horns anyway it's sort of a moot ( or in this case mute) point.:)
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Hi Marin,

If there's a set of Kahlenbergs sounding, you'll hear them! The point being IMO compliant horns are super loud.

The regs call for a minimum of 120dB (for <20m LOA) and 130dB (for 20m to 75m LOA). Kahlenbergs exceed this - you'll hear them!

GPB
 
Marin said:
Being as how anyone inside a running powerboat's not going to hear the horns anyway it's sort of a moot ( or in this case mute) point.:)
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Yes, perhaps with the pip-squeak horns most pleasure (you would call "toy") boats possess. Still, it helps to keep doors or windows open to hear what's happening outside (part of keeping a good lookout).
 
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greatpapabear said:
If there's a set of Kahlenbergs sounding, you'll hear them! The point being IMO compliant horns are super loud.

The regs call for a minimum of 120dB (for <20m LOA) and 130dB (for 20m to 75m LOA). Kahlenbergs exceed this - you'll hear them!
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I concur!
 
My observations are that most all pleasure boaters, when sounding their horns (if at all) such as entering/leaving marinas or in limited visibility when a prolonged (4 to 6 second) blast is called for, only sound a short, one-second blast. Maybe many are trying to conserve the compressed air in their hand-held horns, whatever. It's pathetic/wrong. One advantage of automatic horn controls is that the length and interval of the sound conforms to the rules.
 
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greatpapabear said:
Hi Marin,

If there's a set of Kahlenbergs sounding, you'll hear them! The point being IMO compliant horns are super loud.



GPB
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Our air horns are pretty much the same as the ones you have in terms of volume. But even inside our boat they don't sound all that loud. The horns on the Washington State ferries, which make Kahlenbergs and our horns seem like rabbit farts in comparison, are not discernible inside our boat until the ferry is fairly close. And our boat is not particularly loud inside. I've ridden in boats that are far louder.

Sailboaters tend to hear horns when they're a long ways off, of course. But all the powerboaters I've talked to in person about this, like the folks in our club, all say the same thing-- they don't hear horns until the boat blowing them is very close.

And here's an eye- opener for you. We have an acquaintence who's a Washington State ferry officer. And he told us that on the bridge of the ferries on cold days when everything is closed up, they don't hear horns either, other than their own, unless the other boat is real close.

I'm certainly not advocating not sounding horns in low visibility. In fact we'll probably start turning our nav lights on, too, under these conditions in the daytime even though we know from experience that nobody will see them until they're close enough to see our boat itself (and assuming that we even remember to turn them on) . I think FlyWright made a good point earlier.

But I don't think it's a good idea to drive around in the fog thinking that everyone hears you coming because there's a real good chance some of the other boats driving around in the same fog won't.

We use the intercom/hailer to help us hear the horns on other boats and it helps some but only for boats in front of us. The horns are a great safety aid but in low visibility as far as were concerned it's all about radar and how to use and interpret it properly.

We really enjoy boating in the fog. We both like the challenge. It's like flying on instruments which I really enjoyed until I stopped flying landplanes after moving to Washington.
 
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Up to 20m LOA, IMO compliant horns COLREGS need to be heard at 1/2nm. 20m to 75, it's 1nm. So as has been said, not far at all.

I love how the IMO defines the range,

"The range of audibility ... is for information and is approximately the range at which a whistle may be heard on its forward axis with 90 per cent probability in conditions of still air on board a vessel having average background noise level at the listening posts (taken to be 68 dB in the octave band centred on 250 Hz and 63 dB in the octave band centred on 500 Hz)".

GPB
 
Marin said:
We use the intercom/hailer to help us hear the horns on other boats and it helps some but only for boats in front of us.
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Good idea - wish I'd thought of that....

We really enjoy boating in the fog. We both like the challenge. It's like flying on instruments which I really enjoyed until I stopped flying landplanes after moving to Washington.
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I agree - just like being on instruments. I think I've said before, that when I flew for British Airways I gained 5,000 hrs on the 707 - fantastic plane.

GPB
 
Marin said:
......... But even inside our boat they don't sound all that loud. ........
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Run the boat from the flybridge. You'll hear your horns and the other boat's horns! ;)

And you'll have much better visibility.
 
The Kahlenberg D2 air horn produces 132 decibels versus 130 being 50 feet distant from a military jet taking off from an aircraft carrier using the afterburner. The typical air-raid siren also produces 130 decibels.

I hear the echo from my boat's D2 from hills a quarter mile away (sound traveled 1/2 mile) with the engine running. (I haven't attended loud rock-music concerts, so your results may vary.)

The typical small-boat horn produces at least 120 decibels, comparable to a chainsaw.

Comparative Examples of Noise Levels | Real World Examples and Decibel Levels |Industrial Noise Control
Decibel Chart - Netwell Soundproofing Materials & Acoustic Sound Panels
 
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