CBDR and the importance of proper lookout

[kaj]

CBDR Constant Bearing – Decreasing Range might make it harder to spot another, "non-moving", vessel.

It is the first time I come across the term, in this Finnish Safety Investigation Authority report summary, including a figure showing the case. For some it's been a matter of life and death.

A slightly better quality figure is to be found in the original, Finnish language, (pdf-) report. Search for Kuva 7. and while you are at it, have a look at Kuva 1., the VTS-recording, situation 10 seconds before impact.

Edit: added CBDR meaning

 

[david_bagshaw]

Thanks for raising that, Interesting report, so easy to fall into the pit of it does not appear to move so it is ok

 

[Blue_mischief]

In aviation circles known as the blossom effect. See in

Resources - Library Contents - FAA - FAASTeam - FAASafety.gov

 

[JumbleDuck]

In aviation circles known as the blossom effect. See in

Resources - Library Contents - FAA - FAASTeam - FAASafety.gov

A friend of mine was instructing in a glider on final approach when the cockpit went dark ... another glider on final approach was about 3' above him. Diving away was out of the question, because when the nose goes down the tail goes up, so he very, very, very gently cracked open the airbrakes to increase the sink rate slightly. The other pilot had an uncomfortable discussion with the CFI later.

 

[misterhino]

CBDR Constant Bearing – Decreasing Range might make it harder to spot another, "non-moving", vessel.

It is the first time I come across the term, in this Finnish Safety Investigation Authority report summary, including a figure showing the case. For some it's been a matter of life and death.

A slightly better quality figure is to be found in the original, Finnish language, (pdf-) report. Search for Kuva 7. and while you are at it, have a look at Kuva 1., the VTS-recording, situation 10 seconds before impact.

Edit: added CBDR meaning

Is there an English translation about?

 

[Deleted member 36384]

I have experienced this in motocross in sand deserts. Blasting along at speed there is a bush in the distance in the line of travel. It's the only bush for miles around. Concentration is about keeping the bike going, picking the path of least resistance and managing the various undulations and making sure you keep a watch for stuff likely to throw you. The bush is obvious but far away. Then all of a sudden it's a tree and that I swerved to avoid and have high sided the bike making me eat sand.

 

[Roberto]

I do not understand one word of Finnish (maybe Kuva means "image" ) so it is possibly explained in the text, but looking at picture the course of the boat from the left is so straight as to be under pilot. (?)

Similar awful accident,, a powerboat ran into this sailboat, killing the two crew. Look at the conditions of the hull.

 

[JumbleDuck]

The bush is obvious but far away. Then all of a sudden it's a tree and that I swerved to avoid and have high sided the bike making me eat sand.

 

[Triassic]

It's something we learn as part of advanced riding. If you are riding along and see a vehicle apparently about to emerge from a side road it is good practice to change position in the road. The lateral movement makes it far more likely that you will be seen.

 

[kaj]

Is there an English translation about?

I'd say no.

The report is in Finnish and Swedish only. In English there's a press release besides the linked summary.

Summary, as above: "M2019-02 Collision between two recreational craft in the Archipelago Sea on 3 August 2019 "
Press release, as above: "Importance of proper lookout and observation must be emphasized in order to prevent marine accidents"

 

[kaj]

I do not understand one word of Finnish (maybe Kuva means "image" ) so it is possibly explained in the text, but looking at picture the course of the boat from the left is so straight as to be under pilot. (?)

I think a closer look shows the West-WNW path, marked with small red crosses, not to be completely straight. The times to impact, starting with 4.00--3.30..., are situated on the midchannel straight line.

However, in the report it is stated (my translation and bold): "At the time of the accident the boat was not on autopilot according to the helmsman" (of the bigger boat).

 

[Roberto]

However, in the report it is stated (my translation and bold): "At the time of the accident the boat was not on autopilot according to the helmsman" (of the bigger boat).

thank you Kaj
r.

 

[[163233]]

I guess the inverse is target fixation, where you end up tracking into something despite or because of concentrating on it.

 

[Humblebee]

Interesting. Thanks for the link Kaj.

 

[[163233]]

I guess someone has to point out that this is in the colregs:-

Rule 7
Risk of collision
(...)
(d) In determining if risk of collision exists the following considerations shall be among those taken into account:
(i) such risk shall be deemed to exist if the compass bearing of an approaching vessel does not appreciably change;