first time in fog

[rslifkin]

My AT34 came with one puny air horn. I added two other trumpets and one additional compressor with air tank. When I sound horns, I sound like a Hattaris (sp). They expect to see a big 65ft+ boat and I go puttering by. LOL

I've never gotten that effect, but since I put my 3 tone electric setup together, if I hit it coming out of the fairway at my marina (almost no visibility to one side), people on the boats at the outer end of the dock often wince, cover their ears or give me dirty looks. Doesn't help that electric horns are a little more harsh than air, as they don't have that quick fade in, they just snap right to full volume.

 

[w8n4sun]

We spent the last two days practicing running in thick fog between Seattle and Everett, made even more fun dodging the hundreds of fishing boats and three ferry crossing routes. At points we had to go into neutral to avoid a collision and/or waiting for a ferry to cross our bow. Well worth the practice and we learned a lot and getting to know our radar, chart plotter, auto foghorn, AP, compass and manual steering.

Gets real interesting when all you can’t see beyond your bow and radar displays hundreds of targets in your path. Fishing in fog in and around the shipping lane must must get exciting when a ship comes by.

 

[hollywood8118]

If you do put a lookout on the bow, make sure they have good gear.....

Pair the lookout with these and you may be on to something!
HOLLYWOOD

 

[greatpapabear]

If your boat is over 12 metres, the sound level should comply with the Col Regs.

These gorgeous Kahlenbergs do just that and are fully certified.

 

[psneeld]

Pair the lookout with these and you may be on to something!
HOLLYWOOD

The ones I loved on USCG cutters....a bit heavy for my bow.....

 

[Seevee]

When motoring in fog, I find that in so many cases boaters use their radar simply to dodge traffic rather than applying the 'in restricted visibility' rules, and they certainly don't make the required sound signals.

Yes, you must slow down, but this means you must be aware that if your radar is fed with GPS speed over ground (SOG) and course over ground (COG), MARPA will become more and more inaccurate in displaying the opposing vessel's aspect, especially if a tide is flowing, and/or there's a wind. (Fog and wind are common where we're based). Fed with GPS, your radar is said to be ground stabilised.

Remember that the rules all change 'in restricted visibility', and knowing the opposing traffic's aspect becomes crucial.

If your radar is fed with boat speed through the water (STW) and boat heading (BH), your radar's MARPA will be good to go, as they say. In this case your radar is said to be sea-stabilised and will display vessels' aspect correctly.

But overall, it's so important to know how to interpret your radar picture, and how significantly the rules change and what you should and shouldn't do.

Read this chilling accident report from the Marine Accident Investigation Branch:

As the commentary says on page 24, "The radar information displayed on P&O Nedlloyd Vespucci was ground-based, the incorrect format for anti-collision avoidance. It should have been waterbased, in accordance with IMO guidance. When radar is ground-stabilised, the output of data will relate to their ground track and, although accurate, can be highly misleading when assessing target aspect."

Would someone please explain this "waterbased" vs "landbased" radar thing?

 

[psneeld]

Speed through water vs speed over ground. Current is the difference.

 

[Seevee]

Speed through water vs speed over ground. Current is the difference.

Makes sense, but how does the plotter know the current? And really, what difference would that make? Both vessels are affected by the same current, so the track is what would be important... what am I missing?

 

[psneeld]

Makes sense, but how does the plotter know the current? And really, what difference would that make? Both vessels are affected by the same current, so the track is what would be important... what am I missing?

Different sensors can input GPS (SOG) and Speed (water paddlewheel or doppler sensor). Plotters then calculate the difference between the two.

Current at different angles will affect speed differently and depends which one you are using versus what the other guy is transmitting.

Pure radar data is apparent motion.

 

[Seevee]

Different sensors can input GPS (SOG) and Speed (water paddlewheel or doppler sensor). Plotters then calculate the difference between the two.

Current at different angles will affect speed differently and depends which one you are using versus what the other guy is transmitting.

Pure radar data is apparent motion.

Thanks Paul,

Would suspect that paddlewheel or doppler is not that accurate, especially on smaller boats. My experience with paddlewheel on smaller boats is that they are not very good, and often fail. Heck, don't even have one on the current boat. However, I can understand how they would work.

Kinda like true airspeed sensors in aircraft. (but not used for collision avoidance, only nice to play with... even in the jets). Also, the one I have in the plane (which cost 10K) ain't worth a shxx.

Now, back to boats... why wouldn't we want apparent motion and relative motion to each vessel. Who cares if the current affects each boat differently. We see the other vessel on radar and it will plot where it's going (as long as they maintain course and speed). But in the case of the sail boat, I would have done the same thing and reduced power to yield to the bigger boat, and could have argued to steer away from him. I'd bet the smaller boat could turn on a dime unlike the bigger boat. Also, was implied that the sail boat was under sail power, and could have argued to do what's necessary to avoid, even turning the engine on, and releasing the sail. (or what ever the heck they do to unload the sail, I'm a windsurfer and know nothing about sail boats).

In a learning mode for now..... thx.

 

[greatpapabear]

Would someone please explain this "waterbased" vs "landbased" radar thing?

I wrote an article for Passage Maker a few months ago. Did you see it?

Water based = Sea-stabilised. I.e., Radar uses SOG & COG.

Water based = Sea-stabilised. I.e., radar uses Speed through the water and boat heading.

 

[markpierce]

My horns are too loud to permit stationing a lookout forward of the pilothouse.

 

[Alaskan Sea-Duction]

I have these train horns:

https://www.airhornsoftexas.com/collections/train-air-horns

 

[Mako]

For those mentioning having a person on the bow, that's a good idea, but often not practical... I'm generally more inclined to put a person up forward when running in the dark than any other time.

The boats on this forum are generally smaller than 70ft. We are not running 300-1000 ft long behemoths.

So I wonder just how effective it really is to put someone in the bow. Assuming you’re piloting from the house (where your radar and electronics are) then wouldn’t it be more effective to get your watch as high as possible (up on the bridge or up a mast) instead?

 

[psneeld]

The boats on this forum are generally smaller than 70ft. We are not running 300-1000 ft long behemoths.

So I wonder just how effective it really is to put someone in the bow. Assuming you’re piloting from the house (where your radar and electronics are) then wouldn’t it be more effective to get your watch as high as possible (up on the bridge or up a mast) instead?

Agreed, the bow thing on my 40 footer would not help that much and that person would be miserable so quick, probably a lousy watch standard at that point.

The rule of thumb for many USCG cutters I was on...was an outside watch or access to open doors/ports was the important feature. You could hear better and usually see better so if you have a door at the helm...that might suffice.

 

[O C Diver]

One of the features I like on my old Raytheon hailer / intercom / foghorn is the ability to listen with the exterior speaker as a microphone. When the tone sounds, the internal speaker is muted. After the tone, it goes to listening in the intercom mode. On rainy foggy days, it's nice to be inside and still be able to hear maybe 60 degrees to either side of your bow.

Ted

 

[Seevee]

I wrote an article for Passage Maker a few months ago. Did you see it?

Water based = Sea-stabilised. I.e., Radar uses SOG & COG.

Water based = Sea-stabilised. I.e., radar uses Speed through the water and boat heading.

Greatpapabear,


Do you have a link to your article? Still not sure of the advantage. Right now, I'm with the thinking that one really want's to know WHERE they will be, and the track they are making (nothing to do with heading or true water speed). That seems logical, because you will be using the same info to avoid the other vessel.



So, if you're going sideways, or a significant current pushing you to the side, the sea stabilized radar will not clearly show that. The ground based will be clear.


What am I missing?

 

[rslifkin]

The boats on this forum are generally smaller than 70ft. We are not running 300-1000 ft long behemoths.

So I wonder just how effective it really is to put someone in the bow. Assuming you’re piloting from the house (where your radar and electronics are) then wouldn’t it be more effective to get your watch as high as possible (up on the bridge or up a mast) instead?

I'd think yes. Generally, if I need to hear better, my standard is to run slow to reduce engine noise, and if weather permits, roll up the side curtains and open the center windshield so there's less between my ears and stuff outside. At night, I can put someone on the bow seat if needed, but it's a no-go in fog. So I typically make sure there's a second person next to me at the nav station to provide extra eyes and ears.

 

[Chrisjs]

One thing also worth considering is to avoid the "deer in the headlights" gaze. The "lookout" should intentionally sweep the forward direction from port to starboard and back. Unfortunately, most of us do not have eyes in the back of our heads and often structures prevent easy looking over the shoulder to see what is coming up astern.

 

[greatpapabear]

Greatpapabear,

Do you have a link to your article? Still not sure of the advantage. Right now, I'm with the thinking that one really want's to know WHERE they will be, and the track they are making (nothing to do with heading or true water speed). That seems logical, because you will be using the same info to avoid the other vessel.

So, if you're going sideways, or a significant current pushing you to the side, the sea stabilized radar will not clearly show that. The ground based will be clear.

What am I missing?

Hi Seevee,

The link to my radar article in Passage Maker is here: https://www.passagemaker.com/technical/radar-use-fog

Let me know if you want further clarification.

As an aside, I don't put anyone in the bows as a look out. Why? Fog is normally very cold and eyes can become water logged. I prefer I to have my wife 'on weapons' (radar), scanning between 1 mile and 6 miles. Our radar can see better than we can hear.

 

[OldDan1943]

Open the pilot house door, sound your horn and if you get a 2 second echo, you better start backing down really fast. LOL

 

[Mako]

The link to my radar article in Passage Maker is here: https://www.passagemaker.com/technical/radar-use-fog

Good article. However the response by user cj47 was a bit confusing and unclear. Do you have any feedback on his statements?

 

[greatpapabear]

Good article. However the response by user cj47 was a bit confusing and unclear. Do you have any feedback on his statements?

I've looked but can't find cj47 - which is the post number?

 

[Seevee]

Hi Seevee,

The link to my radar article in Passage Maker is here: https://www.passagemaker.com/technical/radar-use-fog

Let me know if you want further clarification.

As an aside, I don't put anyone in the bows as a look out. Why? Fog is normally very cold and eyes can become water logged. I prefer I to have my wife 'on weapons' (radar), scanning between 1 mile and 6 miles. Our radar can see better than we can hear.

Greatpapabear,


Thx for the article. I'm just barely beginning to digest this, but not up to speed.
What I just don't understand, is why you really wouldn't want the track of both vessels for collision avoidance, and track is where the boat is going. Who cares about heading or speed thru the water. You might still have a collision if both vessels speed thru the water is zero and one is more affected by wind than the other....and you'll see this on the radar that is ground stabilized. (Yes, you'll see it on sea stabilized, too).



Now, I want to see "projected track" based on "track made good". Assuming no one turns, that should give you a collision point... or show if you'll miss the other boat.



But, with all the recommendations on sea stabilized, I need to dig deeper.



Question... are a lot of smaller boats equipped with sea stabilization? Mine isn't even mentioned in the manual.


But thx for the info...

 

[psneeld]

Greatpapabear,


Thx for the article. I'm just barely beginning to digest this, but not up to speed.
What I just don't understand, is why you really wouldn't want the track of both vessels for collision avoidance, and track is where the boat is going. Who cares about heading or speed thru the water. You might still have a collision if both vessels speed thru the water is zero and one is more affected by wind than the other....and you'll see this on the radar that is ground stabilized. (Yes, you'll see it on sea stabilized, too).



Now, I want to see "projected track" based on "track made good". Assuming no one turns, that should give you a collision point... or show if you'll miss the other boat.



But, with all the recommendations on sea stabilized, I need to dig deeper.



Question... are a lot of smaller boats equipped with sea stabilization? Mine isn't even mentioned in the manual.


But thx for the info...

I can't be sure but it looks like the option (sea or land based) really applies to ARPA/MARPA...not the actual screen picture.


Relative motion, specifically constant bearing decreasing range is still all you need to avoid hitting something. The ARPA/MARPA just gives quicker info and info beginner RADAR usuers may have trouble with when in the SHI*.....

 

[greatpapabear]

Greatpapabear,

Thx for the article. I'm just barely beginning to digest this, but not up to speed.

What I just don't understand, is why you really wouldn't want the track of both vessels for collision avoidance, and track is where the boat is going. Who cares about heading or speed thru the water. You might still have a collision if both vessels speed thru the water is zero and one is more affected by wind than the other....and you'll see this on the radar that is ground stabilized. (Yes, you'll see it on sea stabilized, too).

Now, I want to see "projected track" based on "track made good". Assuming no one turns, that should give you a collision point... or show if you'll miss the other boat.

But, with all the recommendations on sea stabilized, I need to dig deeper.

Question... are a lot of smaller boats equipped with sea stabilization? Mine isn't even mentioned in the manual.

But thx for the info...

...and there's me thinking I'd made it so clear in the article! But you are right, it takes a great deal of learning to know how to set up and use your radar.

Maybe I can answer your last question, first. No, very few smaller boat radars are not equipped for sea-stabilisation. Why? It's far more costly and complex for the owner to install accurate boat heading and speed through the water than to feed the radar with GPS SOG and COG. In fact, when I first wrote the article for another magazine a number of years ago, one of the manufacturers I contacted told me quite openly that they didn't want to mention ground- or sea-stabilisation since it might lead to legal challenge. 'It's better not to mention it and leave it up to the owner to know what he's doing.'

Obviously, the key issue for any user is to know if there's a risk of collision. Here, the EBL is by far the best indicator.

If there is, the aspect of the opposing vessel is the next key so you know the correct action to take. Again, bear in mind the Col Regs completely change when in restricted visibility. Being familiar with your radar, its limitations and the Col Regs is vital.

Interestingly, the merchant seaman's radar course is many days, plus practicals....

 

[Seevee]

Thanks GPB,


While I'm still learning my radar (and most everything about boating), I've got a reasonable handle on it, and feel comfy.


I've taken radar classes, but in aviation. It's very similar, but for a bit different reasons. They are both used for collision avoidance, but the boat is for colliding with other vessels and objects, and the aircraft is for colliding with nasty weather.



The aircraft radar has stabilization, but for a different reason. In my plane I can set it up to align with track, heading and in either case see the effect it has. I MUCH perfer the track, as it provides a better picture.



Now, in the boat, I can put the side of my boat within 2 feet of another boat or object (at slow speed), with zero vis. (Yes, I have a spotter when I practice that). And with a small boat (less than 75ft) we are MUCH more maneuverable than a bigger boat, so I can say that I'll take whatever extra steps to avoid a big one by a LOT more than I will a smaller boat.


So far, good. But often I'll choose not to run in the fog.



Now, another thing... fog is RARELY zero/zero. There's usually "some" vis, and even 200 feet is a HUGE amount when operating in fog, certainly enough for me to avoid something, but I'll be only going 3 or 4 knots.



Now, when you get a light precip (snow is the worst) and a heavy fog, one might not see the dock or boat that's 20 feet along the side. I could argue to really avoid this.


Just my experience..... but WILL figure out this "sea stabliized" stuff.

 

[Mako]

I've looked but can't find cj47 - which is the post number?

Bit dramatic...

cj47
10 months ago
Since first operating, maintaining, trouble shooting and component level repair of maritime radars to 1/4 megawatt on up to 12 ft antenna in 1968, to date I can only recommend you (1) use 'head up' only!!! (2) NEVER OVERLAY YOUR RADAR ONTO A CHART DISPLAY, you will die. (3) Never mount your radar display such that it faces forward in the wheelhouse requiring you turn around to view the screen, no matter how your wheelhouse is configured. (4) You've spent your entire life reading maps North up, other than thinking head up will some how impress guests, it serves no useful purpose. Remember, not all 'boat show' features are actually useful or should actually be used underway.

 

[Hippocampus]

Agree with the overlay statement. Even if you only have one screen available better to use the split screen function with radar and AIS on one side and chart on the other.
The deck light statement is interesting. See fish boats all the time where you can’t even find the running lights because the deck lights are blasting as they work. Same with cruise ships but they’re not a problem as all have AIS. Find some people do better when they close their eyes while listening and turn their heads like they were scanning the horizon. Others find cupping one ear then the other helps. Been impressed by how wrong you can be in localizing the sound source. When finished with a sound scan then open their eyes and do a fresh visual scan. Seems to help with that as well. Sometimes you can’t see the vessel but can see the disturbance they make in the fog. Sometimes polarized sunglasses help. Particularly if it’s clear and sunny above the fog.
Never had an IR camera on a boat. Does anyone here use a FLIR and does it help in fog?
Been told if you have an aid and it’s working and you don’t use it when needed in the event of collision or mishap admiralty court will assign some degree of blame to you.

 

[FlyWright]

Do any of you guys communicate with Vessel Traffic Service (VTS) of USCG to advise them of your position and intentions and receive traffic advisories of vessels they are aware of in your area? I always check in with them when operating in main channels during fog. We have lots of commercial traffic plying the waters here and they're all on VTS.

I don't have AIS, but use the cellphone repeaters like Marinetraffic and Boat Beacon to announce my position to others with Marinetraffic and observe local AIS targets...albeit delayed somewhat.

My must-haves in fog are

Autopilot
Radar
Redundant chartplotters
Auto fog horn (Fogmate)
AIS or Marinetraffic
VHF Comm with VTS in channels
Good pre departure planning