By How Much Do You Slow Down In Fog?

beejay190

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I have yet to make my first voyage to the C I and , following the recent fatal accident between Condor and a fishing vessel, wonder by how much one should reduce speed where visibilty is severley reduced.
 

SteveE

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Having done the Solent to Jersey trip in thick fog, we were down to 6 > 10 knots, but it in my view comes down to what you as skipper feel is the right speed for the situation...

One thing we did experiance we picked up a large ish boat on radar, put on MARPA and planned a course to go behind, had we not been going so slow we would have probably had a major accident as the ship in question was trawling and had its nets out....
 

DAKA

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I have yet to make my first voyage to the C I and , I wonder by how much one should reduce speed where visibility is severely reduced.
edited quote

In my opinion you should repost or edit your question without mention of the incident as it effectively gags much of the sensible advice you will attract .
 

[2068]

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Off the plane, but reasonably well powered up so that I can sprint out of the way if required. e.g. 8-10kts, and prepared to stop if needed.

Planing in fog is a bit mad, imho, even with good radar.
 

Solitaire

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I have yet to make my first voyage to the C I and , following the recent fatal accident between Condor and a fishing vessel, wonder by how much one should reduce speed where visibilty is severley reduced.

Falls under the definition of safe speed - a speed suitable for the conditions! If you have radar then switch it on. Get all crew to get into life jackets if not already. Open all your windows/remove covers/helm from fly-bridge so you can hear fog signals. You could position crew on the bow to listen, but I would be wary of doing that mid channel - OK for operating in a river but not a good plan IMHO in open water. Sound your fog signal - 1 long blast every 2 minutes. Although given the Condor crew are inside it is unlikely they would hear you!

Check your weather forecast before leaving and also go on line and check viz at channel buoys.

If in doubt, don't go! If no radar, then don't go. Fit a active radar reflector such as a SEEME. If you have AIS , then turn it on!

However, as a commercial vessel the fishing boat should have had AIS anyway, but not sure the vessel was commercial.


This time of year is going to be fog ridden - cool seas, warm air! So be very sure before you go venturing out. Also use a chart and plot a web point web so you can use your GPS in relation to a chart.
 
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timbartlett

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Agree with almost everything Solitaire said except:
...Although given the Condor crew are inside it is unlikely they would hear you!...However, as a commercial vessel the fishing boat should have had AIS anyway, but not sure the vessel was commercial.
Ships with enclosed bridges are required to have external listening equipment.
The main problem is that a small boat's "whistle" only has to be audible for half a mile. In theory, if your closing speed is any more than 15 knots, another vessel could go from out of earshot to collision in the interval between hoots.

AIS isn't compulsory for all commercial vessels: off the top of my head it's something like passenger vessels making international voyages and ships over 300 tons. A 10m fishing boat is neither.

To answer the original question, I'd suggest just below "hump" speed. At (say) 8 knots you will still get there before you start suffering sleep deprivation, and you will be reasonably manoeuvrable without making everyone seasick or rushing into the unseen.

And do bear in mind that fog -- evenat this time of year -- is not inevitable, and that collisions between ships and motor boats are very, very, very rare.

Enjoy it!
 
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Deleted User YDKXO

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How do you define fog? If you mean the kind of conditions in which you can hardly see the bow of your boat, then I'm down to fast displacement speed, say 8-10kts, and praying that there isn't some small sailing boat directly on my heading. We've had a couple of near misses with small sailing boats in the middle of the Channel which did not register on the radar at all.
If you mean the kind of viz in which you've got a chance to react, say 50-100m viz, then slow planing speed, say 14-16kts
 

ChrisE

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I'd add that if you don't yet have radar and are thinking of fitting it soon, consider a new broadband radar. We have recently fitted it to our fishing boat. On short range <0.5m it picks up pot buoys, at 400ft range it picks up sea birds sitting on the water. It doesn't miss any type of boat.
 

jfm

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I'd add that if you don't yet have radar and are thinking of fitting it soon, consider a new broadband radar. We have recently fitted it to our fishing boat. On short range <0.5m it picks up pot buoys, at 400ft range it picks up sea birds sitting on the water. It doesn't miss any type of boat.


I'd agree that you should consider it, but do recognise that it is not better all round than a magnetron radar. It offers some advantages, and some disadvantages. A quality magnetron open scanner with digital processing will also pick up and resolve individual sea birds and pot buoys and not miss any boat a bb will pick up. The bb units currently on the market can be better at v short range but generally not on long range. Do your reaearch, and i suppose ideally fit both!
 

MapisM

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We've had a couple of near misses with small sailing boats in the middle of the Channel which did not register on the radar at all.
Now, that's scary.
Which equipment did you have at that time, and how big were waves?
I've never experienced - in any decent sea condition - a totally missing target, even with my 15 yrs old Furuno. Not even the smallest RIBs.
Actually, radar problems are often due to the fact that fine tuning for the specific needs/conditions is not trivial. Much more worth investing some time on learning that, rather than forking out money for the latest technologies available, IMHO.
 

strakeryrius

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I would agree that the safe speed will be dependant on exactly how thick the fog is, and whether you have early warning electronics like RADAR.

Personally I have RADAR and at vis of <100 metres I keep it down to about 8 knots.

If the vis is over 100m then I throttle up just enough to get onto the plane (for fuel economy) but then back down again to about 12 knots - just enough to stop from falling back off the plane again. If the vis improves then I throttle up. At the end of the day its a judgement call by you as to what you feel comfortable and safe with, so there can't be any hard and fast rules on the subject.
 

Searush

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I can only do 7-8kts & don't have any radar. I prefer to sail if I get caught in fog, this will drop my speed quite a bit (2-4kts) as the wind is usually light. But I can hear engines clearly. If I have my engine on, I don't hear others 'til quite a bit later.

Getting out of the way of a fast moving vesssel that hasn't seen me could be a BIG problem if under sail. :eek:
 

MYAG

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I generally go by the rule of running at a speed that still allows you to stop in the distance you can see to be clear.
 

photodog

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Bizzare how there is so much decent sense posted here... but my experience is that no one actually seems to do this when on the water!

Like Searush I prefer to sail when in fog... your hearing is your best sense.... We have radar but it is down below... and as a consequence with me and swmbo on board it's useless....

A couple of observations..

1) I have never had a close call with a yacht... but plenty with powerboats.... 8-10 knots may be slow for you guys but its brick crappinly fast for us... Summer 2008 had a small peche come out of the fog maybe 30 meters ahead of us... cross stbd to port at about 10 knots.... and disappear.... 10 minutes later same boat came out again.. closer still port to stbd again at about 10 knots... scared the **** out of me. 2007 entering the west entrance at plymouth... thick... Big sealine came up behind and overtook us on the plane... probably doing 18-20 knots..... again almost ****e myself... Nearly had a head-on years ago with the old Torquay MTB ferry.... etc....

2) I have never heard another boat making fog signals. Made plenty myself... but never heard anyone else doing it.

So, please guys... remember that we go along in fog at maybe 3-4 knots... and we cant get out of the way very quick....
 

hlb

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I'd add that if you don't yet have radar and are thinking of fitting it soon, consider a new broadband radar. We have recently fitted it to our fishing boat. On short range <0.5m it picks up pot buoys, at 400ft range it picks up sea birds sitting on the water. It doesn't miss any type of boat.

My 20 year old Raythion will also pick up pot buoys and sea birds, and does not need to be on very short range. But still there is the odd small yacht that it's missed. They all seem to be angular shaped, a bit like the stealth fighter. I could have designed the thing if they'd asked.
 
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I'd agree that you should consider it, but do recognise that it is not better all round than a magnetron radar. It offers some advantages, and some disadvantages. A quality magnetron open scanner with digital processing will also pick up and resolve individual sea birds and pot buoys and not miss any boat a bb will pick up. The bb units currently on the market can be better at v short range but generally not on long range. Do your reaearch, and i suppose ideally fit both!
I would agree with this. After doing my research, getting advice from here and asking a friendly marine electronics engineer proficient with different sets who told me BB radar is brilliant in harbours and for short range but for offshore work you (me) would be better with a good quality digital radar set or if funds permit an HD digital unit. I bought the HD digital unit but have not used it in anger yet.

Fog I hate the stuff but hopefully will be better placed now with the help of gizmos and electrikery

Martin
 

MapisM

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I generally go by the rule of running at a speed that still allows you to stop in the distance you can see to be clear.
Sensible rule, but you've obviously been lucky if you could always stick to it.
Sometimes (and particularly in some places - e.g. the Venice lagoon), the fog can be thick enough to not see the windlass from the pilothouse...
Pretty much the same as cruising with the canvas on the p/h windows, must be tried to be believed! :eek:
 
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timbartlett

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Actually, radar problems are often due to the fact that fine tuning for the specific needs/conditions is not trivial. Much more worth investing some time on learning that, rather than forking out money for the latest technologies available, IMHO.
When the first few batches of RYA radar instructors were being trained, several of the courses were run at a sailing school that was just a couple of minutes walk from the Raytheon (as it then was) building in Portsmouth. So we often went across so that the wannabe instructors could talk to the tech service guys.

One of the scariest comments came out in just such a meeting, when the Raytheon man told us that most of the sets that were returned under warranty had all the gain and tuning controls at exactly the same settings as when they left the factory in the first place.

Auto tune is much better now, but auto gain and auto clutter are still nowhere near as good as a manual set-up.
 

photodog

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There's a article by some beardy guy in one of the magazines this month.... Maybe I'll take a look.....;)
 

MapisM

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Auto tune is much better now, but auto gain and auto clutter are still nowhere near as good as a manual set-up.
Agreed 100%. Besides, learning to tweak the controls is very helpful also for the other usage of radar - i.e. monitoring storms movements.
Something many boaters are not even aware of.
 
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