The Next Advance in Enhanced AIS Collision Avoidance


I can say that I often do not understand what some mariners are attempting to say on the VHF. A lot of mariners also appear to be reluctant to talk on the radio.


The question is are mariners making an error when they attempt to make their intentions clear and less ambiguousness or is the problem that the VHF is a terrible tool to use for that purpose?


The VHF is a good tool, but it’s old technology, like paper plots on a chart. In the era oof New tech, like ARPA , AIS, and ECDIS, there is room for further improvements to situational awareness, such as you suggested. That doesn’t we should stop looking out the window or using the radio.


It is when somebody’s push-to-talk switch gets stuck and they are oblivious to it.


Yes, that’s a good way to put it. I don’t know how using the AIS would work in practice but we should reevaluate how we are doing collision avoidance given changes in tech.


If you look at the problem from a different point of view; say we had to design a system from scratch today to communicate what our intentions were in a risk of collision situation, would voice VHF be considered the best alternative?

Or would just put out safety notices telling watch officers not to use the VHF?


AIS is the only technology that provides the names of other ships, flag, type of ship, dimensions, destination, etc. This info is best presented on the ECDIS.


Local transponder/data network among vessels in range, with automagic maneuvering protocol such that each vessel would be directed so as to avoid collision with the smallest total amount of maneuvering energy over the full network. This would naturally favor small vessels maneuvering more than large ones. Priority for constrained by draft, fishing etc would be baked into the protocol. Projected tracks would be laid out on the plot and automatically executed unless the man on watch hits a protest button.

Vessels would be equipped with long foam bats to gently shove unequipped small craft out of the way. The expense of the bats would be offset by the savings in windows and clear-view screens. There would be a thriving black market in software designed to increase priority of the vessel it’s installed on.


There’s no judgment or criticism in the brainstorming phase.


They’re nicer than firehoses and cheaper than laser cannon. A more technical approach would be high-capacity liquid-ammonia hoses to temporarily freeze the water around interfering craft. Or of course propane or LNG if you don’t like the ammonia smell.


When the bridge watch is in heavy traffic and high work load comms by VHF take a lot of time and attention, and are very prone to errors. This is why VHF use is discouraged, better to just live with elevated risk of unconfirmed avoidance plans.

When using VHF both parties must give the radio their full attention at the same time. Neither party can pay attention to anything else except wait while the other is assessing the siltation and calls back to confirm.

With VHF passing arrangements are not stored anywhere (just verbal) for verification etc. Not in visual format (not on the screen of APRA where all the other info is).

It’s similar to the difference between a text (the AIS system) and a phone call (the VHF). Text messages don’t have to be responded to in real time.