In the year 1983, my ship was approaching Tokyo bay.
The previous 3 days had typhoonic weather, and there would be a mass exodus of all ships and Japanese coasters, eager to reach the next port, or continue fishing, after getting detained for 3 bad weather days.
On a 12 mile range, in not so good visibility I could see maybe around 300 ships targets. Well we had an ARPA radar, and the OOW had called me up to handle the super dense crazy traffic . In this area, nobody knows ROR. All react like fishermen, unlike the English Channel..
My third mate continued acquiring targets Ping Ping Ping on the radar, when he should be concentrating on visual mode, with visibility around 2 miles. I told him to change over to RELATIVE trails, as i noticed that he was on true trails mode. I also told him NOT to look further than 6 miles on the radar, cutting down his attention area.
I called up the Radio Officer on bridge and asked him to change the CRT tube of one of the radars with a brand new one, in the spare locker. The old tube had a burnt centre spot and had NIL persistence of vision.
He did it in a jiffy, and since it was sunset, i could see the good persistence of vision, without the black hood and screen. -- like the modern day TV type radars giving relative trails.
I them told the OOW to put off the ARPA and use only radar mode. Totaly shocked, he told me to repeat my command , thinking he had heard wrong. I again said " Put off the ARPA, I dont want you to acquire targets on ARPA".
I took the ship into Yokahama harbour , and then handed over to the pilot. By the time he took over the visibility was around 1 mile.
The nervous Jap pilot was literally running around like a monkey, peering through the binoculars, frothing from the mouth, bumping here and there, running back to the ARPA and acquiring targets ping , ping, ping all on TRUE vectors. It was a sight to see.
Thrice i had to warn the pilot that we were on collision course and make the decision to alter course with pilot on board, whcih is bad protocol , but within maritime law traditions.
Much later, at port, with cargo work in progress, the OOW ( third mate ) was hanging around my cabin, -- he wanted to speak to me.
He said : " Sir, you had hundreds of targets, you were at absolute ease without an ARPA, and made several alterations, which i noticed were all perfect and optimum ones, in such dense traffic, with poor visibility. I am impressed. What was the secret? "
I said " Son, it is hard to explain all this to a boy who prefers to wear a digital watch , still i must try"
Here is the gist--
If you notice any of your friends , wearing a digital watch, make a mental note that he is NOT TOO BRIGHT.
This is the way the human brain works. Smarter blokes wear analogue watches, which does not tax the brain. I do not want to digress. That will be another blog.
We had more than 300 targets on a 12 mile range, all cross traffic, with absolute chaos.
Or say 150 targets forward of beam . Most of the ships had slowed down, and some fishing vessels were stopped..
Now, how many blessed targets could the ARPA acquire? May be about 20 or max 25? ( on that old radar it was just 15 nos )
What is the big idea in acquiring 15 out of 150 targets, leaving 135 unacquired? How do you know the 15 you had acquired were actually hostile targets?
Even if you had acquired 15 hostile targets by sheer divine luck, can the human brain take in so much digital information.
Now if you were looking only at the analogue TRUE vectorARPA lines, like what the Jap pilot did, what can you make out of it? Are you interested in knowing the TRUE course and speed of a target? For what?
At sea every target is round. It does NOT have a bow and a stern in bad visibility. It is RELATIVE, RELATIVE, RELATIVE on bridge-
Why did i choose to change the radar CRT tube ?
Because the persistence of vision afforded gave me RELATIVE trails of all the 300 targets. Any such trail produced in the opposite direction gave me a ready made RELATIVE ARPA vector.
I could instantly see which all targets were hostile. (The reversed relative trails pointing to the radar centre spot )
I could see several targets making crazy emergency alterations of course , by checking out their curving relative trails. I could make out which all fishing targets were stationary, as they gave a parallel trail, of fixed length, based on own ship's speed.
I could see that the ships that did not leave a trail ahead of me were going in the same direction as my ship. I could see who all had slowed down.
In fog, if any Navigator or Pilot, uses TRUE vectors on ARPA, only god's grace is saving the ship.
This foolish idiot will think he is in full contraol, while in reality , he is NOT-- he is a most dangerous man to safety of life on baord.
The only way TRUE ARPA vectors will help, is when you are in a TSS, you would like to know who all are following the TSS scheme as, the ROR is different in TSS. You get to know the true course of the target. Also you can find out which fishing vessel is stopped ( with her nets down/ or sleeping ! )
RELATIVE TRAILS GIVEN BY RADAR PERSISTENCE OF VISION , PRODUCED IN THE OPPOSITE DIRECTION IS SAME AS RELATIVE TRIALS ON ARPA, WITH THE ADVANTAGE THAT YOU DON'T HAVE TO DO PING PING PING, OR BOTHER ABOUT LOST ARPA TARGETS AND ITS ASSOCIATED DISTRACTING ALARMS.
On modern TV type radars , you have an option of pushing a RELATIVE TRIALS button, and finding out a single hostile target among 150 ahead of you, in one single glance.
This system is the world's best lookout man, in heavy traffic.
If you have fed in the timing for the trail length as 3 minutes , all it requires is for a very small boat to come up to the crest of a swell , 3 times in a period of 3 minutes, and it will be pinged.
So you can ask any OOW, will you have 10 lookout men on each bridge wing, or a nice RELATIVE TRAILS radar screen, which option he would prefer? Only an absolute idiot will say 10 lookout men.
After all what will the lookout man tell you? Sir, I can see a light 1 point on port bow--blah--blah-- after a dozen times of this stupid charade, you will go out of your mind, in frustration, for this type misleading information with 150 targets in front, means nothing to you-- right?
At anchorages , use radar in plotter more, zoomed in, with own ships past TRACK on.. The GPS antenna will leave nice doughnut patterns around your ship's anchor. Even a small shift of 20 metres due to stern yawing will be drawn on the screen.
At sea , you must move with the times.
Morons ashore who do not have an iota of your anti-collision experience will write fancy circulars , and try to brainwash you with his idiotic nonsense. You don't have to accept that.
A week back i did my re validation course , for my Certificate of Competency, and an old ex-captain, with 1/25 of my anti-collision experience was lecturing merrily how to avoid collision with various fancy slides.
But then sometimes you let it be--
-- we cant take on this crazy world and win in one single day , right? I went there to get a certificate , after being a student for 2 weeks , and i got it!
Note: This post is the most valuable of all my Naive series posts.
CAPT AJIT VADAKAYIL ( 28 YEARS IN COMMAND )