Channel Crossing and AIS

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richardbrennan

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I am planning to cross to France this year which will be the first Channel crossing since I fitted my AIS transceiver. May I ask what other forumites set the time and distance alarms to; obviously there's a balance between having sufficient warning of potential collisions and picking up every ship in the Channel.
 
Frankly, on a channel crossing alarms should probably be off and a regular watch made on targets.

There are so many targets alarms become irritating.

Is your targets are displayed on a plotter, life is easy!

Good luck and enjoy the crossing.

Tony.
 
As said, keep a good watch for ships. I use my AIS (which picks up at around 20+NM) to supplement my judgement. Remember that some vessels don't have to use AIS (e.g. naval vessels) and some may be turned off or they are just too small to have AIS.
AIS is useful in alerting you and confirming your judgement as to CPA, but like everything it is not the "be all"
 
Agree.

In my case southern N.Sea with a reasonable amount of traffic.

I don't bother with alarms - just keep monitoring.

Plus, if you run a computer (as in my case, as well as a chart plotter) Opencpn's AIS CPA graphic function is excellent.

Jabs said:
Frankly, on a channel crossing alarms should probably be off and a regular watch made on targets.

There are so many targets alarms become irritating.

Is your targets are displayed on a plotter, life is easy!

Good luck and enjoy the crossing.

Tony.
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TrailerSailer said:
As said, keep a good watch for ships. I use my AIS (which picks up at around 20+NM) to supplement my judgement. Remember that some vessels don't have to use AIS (e.g. naval vessels) and some may be turned off or they are just too small to have AIS.
AIS is useful in alerting you and confirming your judgement as to CPA, but like everything it is not the "be all"
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why do you monitor vessels 20 mls away
 
My AIS displays on the plotter, but it's at the chart table hence my preference for an audible alarm. CPA of 1 NM sounds about right to me, I can also set a time and about 15 minutes would seem reasonable?
 
richardbrennan said:
My AIS displays on the plotter, but it's at the chart table hence my preference for an audible alarm. CPA of 1 NM sounds about right to me, I can also set a time and about 15 minutes would seem reasonable?
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With a big boat doing 20kts, then 15min is 5nm away. Doesn't really tie up with your 1nm alarm
 
richardbrennan said:
May I ask what other forumites set the time and distance alarms to; obviously there's a balance between having sufficient warning of potential collisions and picking up every ship in the Channel.
Click to expand...

I really wouldn't bother with an alarm, it'll only likely spook you while you're doing something important like making the tea.

Try using a compass and you"ll soon see who's likely to come close but don't let that worry you either as they will see you and make the appropriate adjustments. Just keep a consistent course.

If you don't believe me just try and hit one of them. I dare you, in fact I double dare.


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shaunksb said:
I really wouldn't bother with an alarm, it'll only likely spook you while you're doing something important like making the tea.

Try using a compass and you"ll soon see who's likely to come close but don't let that worry you either as they will see you and make the appropriate adjustments. Just keep a consistent course.

If you don't believe me just try and hit one of them. I dare you, in fact I double dare.


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Yes the Autohelm personal compass is very good for ship tracking
 
Wouldn't want to be closer than 1 mile in open water. Opencpn is set to flag up anything predicted to be within 2 miles in the next 40 minutes. But no audible alarms - I just keep an eye on the screen and compare with the Mk 1 eyeball, targets that meet the criteria show red.
 
My understanding is that the set will clock up an alarm for a target that when the CPA will be within 1 NM, not at 1 NM, so I would get a 15 minute warning if the CPA will be within 1 NM.

Have I got this wrong; I have a Digital Yacht AIT2000 with a Garmin 5012 plotter?
 
shaunksb said:
They will give way to you even if they are in the TSS.

The TSS is wider than a wide thing and your boat is likely to be less than 50ft.


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My understanding was that the col regs require small boats crossing a TSS to give way to ships using the TSS.

It has also been my observation, based on a number of channel crossings from the Solent to Cherbourg/ Channel Islands, ie not crossing a TSS, is that the big ships assume that yachts are motor vessels, and thus those approaching us from port will give way, whereas those approaching from starboard stand on, regardless of whether we're sailing or motoring.
 
Kwik Decision said:
My understanding was that the col regs require small boats crossing a TSS to give way to ships using the TSS.

It has also been my observation, based on a number of channel crossings from the Solent to Cherbourg/ Channel Islands, ie not crossing a TSS, is that the big ships assume that yachts are motor vessels, and thus those approaching us from port will give way, whereas those approaching from starboard stand on, regardless of whether we're sailing or motoring.
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Wrong, they have to give way. I avoid tss were possible as you have to cross at 90deg

They know the rules, trouble is the small change they make, makes sailors nervous
 
richardbrennan said:
My understanding is that the set will clock up an alarm for a target that when the CPA will be within 1 NM, not at 1 NM, so I would get a 15 minute warning if the CPA will be within 1 NM.

Have I got this wrong; I have a Digital Yacht AIT2000 with a Garmin 5012 plotter?
Click to expand...

Sounds correct to me

My only issue with this was when fishing boat fleets ahead - happy to go closer than 1 nm to these slow moving targets, but spotting the one or two blips that are coming at 20 knots that are hidden behind them is the priority to spot.
I wish the Raymarine alarm allowed you to mark One target and silence for this, leaving alarm to warn if new one comes into zone, but not found a way for selective alarm suppression
 
For Channel crossings AIS alarms are a bit of a pain, so I turn mine off.
For other trips I set CPA to somewhere between a half and two miles, then turn it off!
I set the TTCPA to between 15 mins and an hour and that stays on.
The alarms depend on if it is a coastal trip or a long trip and I'm snoozing.
The rationale is that I don't want alarms going off just because I am pointing at something some way away that might be in a Marina or way over my horizon.
As said in a previous thread on this subject, when your alarm goes off, make note of the targets COG then, when it gets closer you will know if it has changed course, and in which direction. If he hasn't changed course and will pass too close for comfort, you can call him up and ask what his intentions are.
Crossing the Channel, I have found that about 95% of those that AIS indicates will pass at less than 500m will have changed course without challenge.
 
Jabs said:
Frankly, on a channel crossing alarms should probably be off and a regular watch made on targets.

There are so many targets alarms become irritating.

Is your targets are displayed on a plotter, life is easy!

Good luck and enjoy the crossing.

Tony.
Click to expand...

This.

The alarms are for open sea when you're not continuously monitoring traffic. In congested areas like La Manch, someone should have his eyes glued to the radar screen, and the alarms are a distraction.

We find collision avoidance in heavy traffic areas works best with one person at the nav table doing radar and AIS, and another at the helm with a HBC. Even with AIS, you sometimes need to keep notes about how the crossing is developing.

With AIS, many Channel crossings which previously seemed hairy turn out to be doddles. Because you can instantly distinguish a problem from a non-problem, and surprisingly often, maybe half the time, you can just waltz across without any problematic crossings.

Just starting to use AIS, take advantage of the new level of information you have to recognize whether ships have maneuvered or not, when you are under sail or otherwise stand-on. They often do it at 10 miles out, and do it to pass ahead of you with 1 mile CPA -- typical standing orders. If you can observe the maneuver, then you know they've seen you. The crossing will still look like a collision course with a HBC.

If the ship has not maneuvered at 4 miles out, then that's the moment to take action yourself.

You will find doing collision avoidance far more pleasant, giving far better situational awareness, with AIS.

Good luck.
 
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