Navy and AIS?

Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
A U G... There is a lag in data transmit for A and B transponders in accord with the AIS protocol. A (commercial vessels) more frequently based on what is called a "Slot Map"(a map of available times to transmit) managed by the transponder and the AIS satellite/ground system. The update rate ranges from 3 minutes for anchored or moored vessels, to 2 seconds for fast moving or maneuvering commercial vessels, the latter being similar to that of conventional marine radar. And then B (pleasure craft) transponder which follows a similar slot map plan but at a slower refresh about ever 30 seconds.

Add to this protocol there are individual systems some operating inefficiently and some a little glitchy. That your display has the occasional hiccup should be expected. It is a reminder not to put all your faith into one system.
 
Jul 29, 2017
169
Catalina 380 Los Angeles
The straits where the McCain collided with a tanker are the busiest in the world by far. I believe that where the collision took place is where there is a huge bend (turn) in the traffic lanes. Is it possible that this was the furthest point in the ships patrol line and while trying to cut across the strait to make a 180 it misjudged and allowed the tanker to T bone them?...Just saying.
 
Apr 4, 2016
201
Newport 28 Richardson Marina
All the talk about AIS is interesting but not helpful because a vessel is still required to maintain an adequate watch.
Having stood thousands of hours of radar watch I know first hand that different frequencies should be used for different situations due to range shadows, clutter and many other things. A simple mistake like having your display set to a long range frequency radar instead of a short range can effectively make you electronically blind to a 1000' tanker 2 miles away. All of the long range Aegis class weapons radar is useless in close quarters navigation that's why you still see the small antennas with 25 mile range on these big warships.
 
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Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
My experience with sailing in proximity to large US Navy ships comes mostly from the Mayport area. Standard procedure seemed to be for the inbound Navy ship to hail on VHF 16, identifying himself only as "warship" & state his intention to enter the inlet as he made his final turn, warning all traffic to stay clear. Once, I had a hard time getting a 35 Beneteau well clear of the channel before he barreled down on my former position. I had no expectation that he would slow down nor divert course to avoid collision, regardless if he saw me or not.
 
Jan 4, 2010
1,037
Farr 30 San Francisco
But in the McCain collision the other ship was on AIS and very near to the McCain. The rest of the World saw that ship, (marine traffic . com) why didn't the McCain. Ideally you would use eyeballs, charts, radar, AIS, GPS etc etc to build the best picture of the environment around you. My little chart plotter, AIS combo would have seen that ship, told me if I was going to bump or not. Why oh why couldn't the McCain see it?
 
May 28, 2015
275
Catalina 385 Long Branch, NJ
I'm surprised nobody else has raised this question ... it takes two to tango ... every vessel and every crew is responsible for avoiding collision ... why no questioning the commercial vessel? To those who criticized the navy crew and suggest merchant marine training is superior, aren't both crews at fault in a collision? What am I missing?
 
Nov 26, 2012
2,315
Catalina 250 Bodega Bay CA
MO: nothing. In tight quarters the Navy ship probably couldn't avoid the other vessel hitting it. Chief
 
May 28, 2015
275
Catalina 385 Long Branch, NJ
MO: nothing. In tight quarters the Navy ship probably couldn't avoid the other vessel hitting it. Chief
Okay, then for those who hold the commercial seaman above the navy, why is there no discussion about what the commercial crew did/didnt do?

Full disclosure, I'm the nephew of a Retired Navy Master Chief, the brother of a Coast Guard officer, and my cousin's son is a SEALso I may be biased but I've seen the physical, emotional, and mental training and discipline first hand ... none of the collisions make any sense unless there is something we aren't being told which is the most likely scenario.
 
Nov 26, 2012
2,315
Catalina 250 Bodega Bay CA
An off line discussion of this subject has prompted a comparison to terrorists using trucks to kill. Chief
 
May 28, 2015
275
Catalina 385 Long Branch, NJ
An off line discussion of this subject has prompted a comparison to terrorists using trucks to kill. Chief
I didn't want to say or think it ... but a combination of that and/or cyber-intrusion are the explanations that make the most sense. One incident is an accident, four incidents (I think it has been four) is a very bad pattern.
 
Jan 4, 2010
1,037
Farr 30 San Francisco
In this instance,it looks like the commercial vessel was likely "at fault" but you go you-tubing and you can see AB destroyers turning around in 30 seconds accelerating from 0 to a lot in seconds. Those suckers are quick. How did a Corvette get tagged by a Winnebago? The Alaric is what 100 ft wide the McCain only had to move a few hundred feet and all would have been well.
 

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
When AIS first came on the scene I was an early adopter on on AIS B. The commercial traffic were required to be on AIS A. There was one tug company on the bay that must have gone with the low-price, technically acceptable AIS vendor becauase all their tugs showed up on AIS as moving in reverse. It is a great technology, it generally works well, but you have to have eyes on the navigation situation. Trust but verify.
 
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Jan 4, 2010
1,037
Farr 30 San Francisco
Sure but today the kinks are worked out. The Alaric track looks good and solid not jumping around. Does the Navy not look at AIS?? It sure seems they have given up on lookouts.
 
May 24, 2004
7,129
CC 30 South Florida
Navy sailors are not skilled career mariners; they are mostly trained to do a specific function for the length of the on the water deployment. Over reliance in technology over training for seamanship is part of the problem. The world has changed, the new generation relies on computers to do their job and when these fail they are at a loss.
 
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Nov 26, 2012
2,315
Catalina 250 Bodega Bay CA
I say again........Sailors are taught basic seamanship in Boot camp. Some fields get more training in their advanced schools, especially all the deck hands such as Boatswain Mates. Yes, many are highly skilled mariners and spend much of their careers at sea. As an Electronic Tech. I was part of the technical element but still trained in at sea safety and seamanship. Deck hands are who man the helm, not Techs, not officers. They are specially trained for this job.
If you are not knowledgable about how the US Navy operates it would be best to say nothing. Chief
 
Nov 13, 2013
723
Catalina 34 Tacoma
You have to wonder if meth and H have found its way onto the bridge. The people that use that have one thing on there mind.
 
Nov 26, 2012
2,315
Catalina 250 Bodega Bay CA
Head Sail: I assume that you are referring to the commercial vessels as that is not a part of our US Navy! Chief