What is with 2nm CPA’s

What is with all this 2nm cpa nonsense that US flagged ships, drilling rigs and floaters have been asking for in the GOM? It’s pathetic and as far as my understanding is the offshore installations only a need .25 safety zone. I’m sorry but if you want a 2nm CPA you can take it from your end, 1 nm or even .5nm is more than enough for me to be comfortable


For you, yes, you can maneuver easily without a mile of riser hanging below you, when something goes wrong. Some of that angst may stem from 9/11 too. My drillship standing orders (10 years ago) said make VHF contact for CPA’s less than 2 miles so you know that they’re awake and see you, call me for contacts with less than 1 nm cpa AND you can’t reach them by radio.


Yeah I understand that with drill ships or vessels engaged in critical operation I don’t get it when it comes to the semi permanent platforms and especially don’t understand it with the conventional us flagged ships.

I have been regularly transiting the GOM for the last 13 years but this is a trend I have only started to see in the last 2 or 3, are some of you in other company’s being required to have 2nm CPA’s? Or is this driven from something else? It just seems a little over the top.

That is reasonable you are not requesting that other vessels give you a 2nm CPA just to contact them. What I’m annoyed by is vessels using 2nm as a required cpa and it seems like a new trend.

They can request all they want. If you don’t want to give them 2nm, then don’t give them 2nm. It’s a request.


It’s just in case your vessel is being navigated by the US navy. 2nm gives a ship time to respond when you agree to do something and then do the complete opposite to bring the CPA to 0.


This. There’s nothing wrong with a ship requesting any cpa they want, just call them and tell them you’ll be closer than that.

Somebody that’s paying enough attention to call probably isn’t what they’re worried about.

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Yes obviously there is nothing wrong with it, I just feel it’s a tad bit over zealous.

I guess what I’m curious about is why is it suddenly so prevalent. We do not have a company policy regarding minimum CPA’s and it is left up to the Master’s discretion. Have any of you had changes in company policies dictating 2 miles? Is it something I’m going to start seeing spouted off from SIRE auditors? Or is it just a “I saw ship X so I it so I can’t let them out safety me” mindset?

2 mile CPA requests have been around for a very long time.

It’s amusing when I’m making 3 knots in heavy weather and some teenage sounding mate on a big tanker doing 15 knots calls to ask for a 2 mile CPA so that he doesn’t have to wake up the Captain.

Sometimes, just for fun, I’ll ask what do you think I should do to give you a 2 miles CPA? I’ll usually get back something like turn 90 degrees to port and increase speed to 15 knots.


I think 2 mile CPA has been on every set of night orders I’ve ever seen while sailing……no exaggeration.


This is from the Golden Ray. Required CPA varies according to circumstance. No specific distance given when own ship is the stand on vessel.

I used 2 miles in the open ocean and 1 mile in crowded sea-lanes as do most other vessels. Using 2 miles when all other vessels are using 1 makes things difficult.

It’s not suddenly prevalent you’re just now noticing it.

Go work on a large ship and your comfort level will change dramatically.


Setting CPA limits boils down to risk management.

A collision at sea is a high-consequence / low-probability event. The risk can be mitigated by increasing required minimum CPAs.

However the cost of requiring 2 mile CPAs in areas of dense traffic is it increases the watch officer’s workload. A 2 mile CPA means more time spent working the ARPA to maintain the required CPA for more distant contacts which means less time watching closer targets visually.


I am never comfortable until the vessel I am meeting has passed clear

The Masters on the last few MLL vessels I have been on state 2nm in open ocean/waters, but that depending where you may be this will not always be possible and that 1nm or even 0.5nm will be the best you can do and to simply contact them (make sure they’re awake and aware of you, as someone else said) and to call them (the Master) if in doubt or need of assistance.

They’re more than aware that asking for 2 miles or adjusting course to achieve a 2 mile CPA can be impossible.

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Y’all are completely missing what he is talking about. These are stationary vessels that are requesting other vessels make large course changes to give them a large cpa and that very well might put them closer to another contact. A little different when it’s two moving ships and they both are altering a little to keep the industry standard shipping cpa.

He did also specify conventional ships so…. yah, I got it.

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In spite of the assumption of the post I am on a large ATB so I do have some understanding of the dynamics involved. Additionally the ships that I see this behavior on are US flagged which are typically not that large

My thoughts exactly, it’s seems like this kind of thinking somewhat handcuffs the OICNW and like it or not I believe it adds stress to the watch keeper because they may be concerned with having to call the master over a situation that in my opinion has more than sufficient safety factor. It seems that something more along the lines of a one mile cpa is acceptable and maybe .5nm if you have confirmed it with the other vessel via the radio. I don’t care how many times you tell a green mate to call you if they feel uncomfortable with a situation most are still going to be nervous and stressing about it.

Really the reason for the post is that I’m curious if it is being pushed down on the vessel from some company or charter policy.

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He wasn’t only talking about stationary vessels though.

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