AIS

[Alcyone]

I hope you guys and gals occasionally pop up to the cockpit and see if there's any other boats about when tearing lumps off each other here in cyberspace.

 

[claymore]

Oops

Gosh - what a vitriolic little thread this has turned into. My tongue in cheek riposte to the Webmeister has certainly brought out the worst in at least one participant.
Sporran Wetters indeed.
Personally I find that even going commando its very difficult to get the back of the sporran mildly damp because of the weight of the cloth used in making the kilt.

Webby is far too modest to say this and no doubt will not thank me for doing so, but in his faithful and modest craft, he has covered thousands of miles - hard open ocean miles - so Jonjo - zip the lip in terms of getting personal.
xx

 

[TheCrimsonVicar]

Why the controversy ?

Personally I've always found my AIS receiver most reassuring when out in thick fog or in an area where you don't know what's going to pop out from behind the next headland or the nearby islands.
Mine receives from both Class A transponders and Class B transponders.
It is very reassuring at night.

 

[Bat21]

Common Sense

AIS is a valuable tool as, is radar and a chart plotter, none of these tools are a substitute for good seamanship, they serve to provide information in order that an informed decision can be made.

How one uses the information available will depend upon all the circumstances at any given time.

I am fortunate enough to have all these aids at my disposal, there has been a great deal of bunkum posted here which is not worthy of any comment.

I would be delighted to share a practical demonstration and discussion with the Webmeister if it would help with his original question.

 

[murraynorth]

I have a Raymarine AIS receiver and it is brilliant when you are entering the likes of Milford Haven harbour - the headland to starboard at the top of the entrance channel completely masks the main harbour (which is over 15 miles in length) and also the huge gas and oil tankers proceeding at right angles (invisible to eye or radar) towards you. AIS shows exactly where they all are - very reassuring for you and nice for the Milford Haven Port people who then don't need the constant irritation of yachties asking about traffic ahead!
One thing does concern me though, if all leisure vessels had an AIS transmitter as well as a receiver, I can see people switching it off because of the huge number of transmissions and alarms.
Personally, I would like to see AIS transmitters limited to commercial vessels only or maybe commercials plus leisure vessels in excess of 24 metres length.

 

[huzar30]

I just raise eyebrows to hear that (some) people are using it to make course alterations for ships that are still out of sight over the horizon or only just appearing ... Don't just sit below looking at a laptop or plotter screen to see how close a ship is going to pass, take a look outside sometimes ... Don't panic and take huge detours avoiding ships seen on a screen

Why not use it to make a course correction for a ship 7nm away? It was a 5 degree change of course on the autohelm. And the problem is? Is this a 'huge detour'? On the contrary, in the end he passed about half a mile in front of me, which is exactly what I wanted.

What, might I ask, would you do? Keep it visual until it's only 2 miles away, realise you have a close quarters situation, then make a 20 degree change in course?

There's also an assumption here that because you have a laptop, you never look outside. This is rather like saying, gosh, he's got paper charts on the chart table down below. Fellow should be up on deck, scanning the horizon. One advantage of the laptop is that it saves time compared with paper charts, and so gives me more time to scan the horizon.

 

[Alcyone]

I have a Raymarine AIS receiver and it is brilliant when you are entering the likes of Milford Haven harbour - the headland to starboard at the top of the entrance channel completely masks the main harbour (which is over 15 miles in length) and also the huge gas and oil tankers proceeding at right angles (invisible to eye or radar) towards you. AIS shows exactly where they all are - very reassuring for you and nice for the Milford Haven Port people who then don't need the constant irritation of yachties asking about traffic ahead!
One thing does concern me though, if all leisure vessels had an AIS transmitter as well as a receiver, I can see people switching it off because of the huge number of transmissions and alarms.
Personally, I would like to see AIS transmitters limited to commercial vessels only or maybe commercials plus leisure vessels in excess of 24 metres length.

Agreed, although if you monitor channel 12, as is recommended, and have a chart to hand, you will hear such things as 'Bro developer, passing Cunjic buoy, outbound' and 'Isle of Innishmore, just cleared the West channel'.

I'm not saying it is not useful, it's just that pretty much the same information is already available.

 

[fmoran]

We have had AIS for the last 2 years showing up on our E120 graphic display and have got to say found it very useful in poor / medium visibility especially in the Western Approaches off Lands End - on the way to the Scillys, the East Coast of Ireland - inside the sandbanks, and North Channel. Generally its ships going almost parallel to to you in the same direction are the major problems - are they going to pass ahead / astern and what action do you need to take to keep clear. AIS is particulary helpful for this as its very difficult to judge their exact course and speed, also you be aware they are approaching before seeing. In 2009 we had to call ships twice - both in the North Channel - one a small Dutch coaster closing in on us slowly from behind for about an hour, he was very polite and said he would drop behind us, and later the HSS from Troon predicted to come within 400M of us out of the mist. We could only see him on AIS ( and radar ) when we called and asked him his intentions. Reply was a stoney silence, then who / where are you - and we are 42ft with the sails up and radar running. Obviously not looking out and he told us he would alter to go astern - a very close shave and a good reason for having AIS if ever there was. One draw back is that none of the AIS enabled buoys around Ireland can yet be displayed on the E120 - a software release is required from Raymarine to fix the problem