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Tony Wilding
15th August 2011, 03:19 PM
HI, i often read of Radar assisted collisions, ? can someone tell me how this can happen, in laymans terms, am completely in the dark. tony wilding.

Mike Line
15th August 2011, 04:18 PM
There are 2 ways to view a conventional radar screen, Ships Head Up or Relative Motion.
Ships Head Up is the older and was the usual view used by many, especialy the "older" members on the bridge. As it says, the radar screen has a solid pointer on the fore and aft line of the ship, port is port, stbd is stbd, and the ship stays fixed to the center of the screen.
Relative motion, is similar to the view of the ship as it moves across a ships chart, ie North is the fixed point, with the ship moving accross the radar screen, in any direction, relative to its compass course.This view is sometimes prefered.
Radar assisted collisions or near misses normaly occure using SHU. The officers brain and the radar do not always inergrate, a ship that appears to be on a parrallel course may in fact be closing, a crossing vessel may be doing the same thing. It is normally solved by plotting the relative courses this a chinograph pencil on the radar screen and joining the dots.
I have not heared of a Radar assisted collision using Relative Motion, but it has probably happened.
I do know of a near miss, caused by a more senior officer switching from one view to the other and not informing the watchkeeper.
A good lookout normally resolves the problem.

Gulliver
15th August 2011, 04:40 PM
HI, i often read of Radar assisted collisions, ? can someone tell me how this can happen, in laymans terms, am completely in the dark. tony wilding.


I’ll try Tony.
Briefly it means that by using the radar,one or both ships)actually collided with each other.
It sounds daft,but if the ships weren’t fitted with radar (as in years gone by) they would(should !) have been following the Collision Regs.with reference to such regulations as proceeding at a moderate speed,stopping and reversing engines and listening for fog signals etc and not proceeding until absolutely certain of the position of the other vessel. They would not therefore normally have collided.Radar has limitations,especially if wrongly used or the information on it is wrongly interpreted by the observer.
Especially in the 50’s and 60’s when radar became more and more common on merchant ships,Masters thought it would give them the ‘edge’ over other vessels ,in being able to ‘see’ them. They thought they could rely on it more,and the other provisions of the Rules,safe speed.lookout etc took second place.i.e. they gave the Master an excuse not to slow down and therefore maintain schedule.Things got better as True Motion radar and other enhancements came in.as well of course the requirement that all Certificated Deck Officers were trained in their use. I don’t think (at least I hope not) that they happen too much these days !

Notable ‘radar-assisted’ collisions were the liners Stockholm and Andrea Doria off New York in 1956;the Shell tanker Sitala and the Niceto de Larrinaga ;and,the British Aviator and Crystal Jewel,both in the English Channel in 1961. All these with tragic loss of life.In all cases it was a slow but steady alteration of each vessel (I think they call this 'the accumulated turn' )to ‘open’ the bearing between them and give the impression that they had a safe passing distance between them.It was found that far from being on a reciprocal course,they were actually on converging courses up until the last minute,when drastic course alteration had to be applied….too late. In the case of the Andrea Doria and the Stockholm,if plotting had been carried out at the distance they were first observed on radar and a relative plot been carried out at regular intervals it would have been apparent of each other’s course and speed.This was not done on the Andrea Doria,and the Stockholm could not see the Andrea Doria visually anyway,because she(the Stockholm ) was in a fogbank…it was also found that Stockholm’s radar was on a much shorter range than should have been,and could not have detected the Andrea Doria….. or been plotting her.
Hope that explains a bit,doubtless others will try to explain more succinctly and thoroughly,but that basically is what a' radar-assisted collision' is.

Gulliver

John Cassels
15th August 2011, 06:34 PM
All the best radar assisted collisions occur in fog , mist falling snow, heavy rain or any other conditions
similarily restricting visibility.
The most notable are when each vessels sees the echo of the other fine on the bow - especially port bow.
Each thinks a small alteration of course to " open up the angle" will be enough. One of them will alter to
port and the other to stbd. usually by small amounts. This small amount will not readily be noticable to
each other and they will alter a little more - the already mentioned cumulative turn.

There collisions are well documented and the basic way to avoid is a large alteration leaving no doubt in
the other guy's mind as to waht is being done.

j.sabourn
16th August 2011, 02:26 AM
All these good intentions re use of radar are ok. If one still obeys the Rule of the Road. For example what does one do in the middle of a fishing boat fleet. I s impossible to plot about 100 targets at the same time. In some cases is best to switch radar off and let watchkeepers and lookouts use their eyes and ears and do what one did before Radar. If you have a collission with the radar on in these circumstances it would be classed as a Radar assisted collission. The present day watchkeepers that I have seen spend all their time with eyes glued to Radar even during clear weather, they have obviously been brought up with it and know no better. God help shipping if we ever lose the modern aids. J.Sabourn

Louis the Amigo
16th August 2011, 05:54 AM
Hi shipmates did any one on this forum sail on any ships with early radar {wartime} or just after? please post with details thanks

John Cassels
16th August 2011, 07:59 AM
Hi shipmates did any one on this forum sail on any ships with early radar {wartime} or just after? please post with details thanks

On my first couple of ships as apprentice - early '60's - the radar was the old Decca mk4 which I
believe was wartime or shortly after. Unfortunatly it was so long ago , can't remember much detail.

Louis the Amigo
16th August 2011, 09:10 AM
Hi Shipmates. Hi John Cassels, Thanks for your reply I would like information on early radar because I have a R.A.F. boffins note book {wartime} with diagrams and notes about the new system of radar !!! and how it was used on the coast spotting planes and shipping , the people who experimented with it then , and who manned the radar towers? R.A.F. men are very thin on the ground from that time, and it was very hush hush so I have been informed ?

Tony Wilding
16th August 2011, 12:44 PM
Thanks for explanations on radar assisted collisions, it seems a case of disorientation, of the operators in relation to ships true courses on a collision course, expect a much clearer picture is obtained by a fixed position radar, i.e. Dover coastguard monitoring 2 ships on a converging course, thanks to all. Tony wilding.;)

John Cassels
16th August 2011, 02:48 PM
Tony , it's more a lack of appreciation as to what the screen is telling you.

One of the cases I was refering to concerned two tankers off the SA coast. They were on NEARLY
opposite courses but slightly converging. One saw the other on her starboard bow and the other the one
on her port bow. Both altered by 5 deg to give the other more room but all the first ship did was alter
into the second ships course. Very easy trap to fall into with small alterations , lack of radar
appreciation and a lack of proper plotting. Both thought they were on opposite courses which was not
the case .
The situation ended up with a number of small alterations by both ships , one always to port and the
other to stbd. By the time both realised what was happening , it was too late to avoid the disastrous
collision which then took place. they only saw each other when a couple of cables away.

Captain Kong
16th August 2011, 04:49 PM
We did the Stockholme/ Andria Doriua collision at College as a good example of a Radar Assisted Collision
Also I was on the old Franconia, I think the date was around 26 July 1956, when we followed the Stockholme out of New York. About five hours later, The fog on the Nantucket Shoals was incredibly thick , Never ever saw it so dense before or since.
The RADAR on the old Franconia was fixed to a window frame and was around six inches in diameter. Possibly the one that was fitted during WW2. it was just a screen and a `spiders web` over the top of it.
Cant remember too much about the operation of it as it is now over 56 years ago. then we had a Mayday from the two ships ahead after the collision. We never saw anything. the Ille de France got there first and took over the rescue operations, The Andria Doria sank the following day. She was hit amidships by the bow of the Stockholme.
We believed that they saw each other on RADAR ahead , so they both altered course to Starboard, then a while later the radar screen showed the opposite ship now abaft the beam so both ships altered course to Port to the original course and then they were both on the collision course again. and so the Stockholme hit her amidships. 51 passengers and crew were killed in the Collision, The was a movie Star, Ruth Roman, on the Andria Doria, she survived.

Gulliver
16th August 2011, 05:13 PM
Tony , it's more a lack of appreciation as to what the screen is telling you.

One of the cases I was refering to concerned two tankers off the SA coast. They were on NEARLY
opposite courses but slightly converging. One saw the other on her starboard bow and the other the one
on her port bow. Both altered by 5 deg to give the other more room but all the first ship did was alter
into the second ships course. Very easy trap to fall into with small alterations , lack of radar
appreciation and a lack of proper plotting. Both thought they were on opposite courses which was not
the case .
The situation ended up with a number of small alterations by both ships , one always to port and the
other to stbd. By the time both realised what was happening , it was too late to avoid the disastrous
collision which then took place. they only saw each other when a couple of cables away.


I remember the one that you refer to: a classic example of a radar-assisted collision.

At about 5 a.m,local time on 21st August 1972.. 93 km.east of Cape Aghulhas,South Africa,…..two Liberian-flag steam turbined super tankers collided, the 4 year old 106,518 dwt American-owned OSWEGO GUARDIAN,( fully laden with crude oil from the Persian Gulf, collided with the 5 year old ,100,613 dwt-ton Greek-owned TEXANITA (bound to Ras Tanura in ballast). The Texanita, exploded with such violence that it was reported that it shook windows and woke people several miles inland from the coast,which itself was twenty-three miles distant from the accident.
The Texanita broke in two and vanished within four minutes.
Forty three crew died with the Texanita, and one aboard the Oswego Guardian.There were only three survivors from the Texanita, including the master, Captain Juorios Salvuardos and only 10 bodies from her were recovered from the sea.
Both ships were travelling at their usual sea speeds speed through fog so dense that the master of the Texanita, who survived, couldn't see the masts of his own ship.Although they had observed each other on radar, neither ship reduced speed. Texanita made only two attempts to plot the course of the approaching ship, the second when it was only four miles off, and the Oswego Guardian made no attempt whatever to plot the course of the other ship.
The chief officer of a Norwegian freighter, the Thorswave, later provided what might be the first electronic eyewitness account of a major maritime disaster. His own ship was in the vicinity and had watched the accident develop on his radar screen. 'I saw these two dots coming closer together together,' he told the Cape Argus newspaper in Cape Town. 'Then the two dots came into one. just then we heard this terrific explosion and felt our own ship shake twice. I thought there was something wrong with our own ship because the explosion was so loud. A minute or two after this I saw two dots coming away from each other. Then one dot suddenly disappeared from the screen.'

There were reports that immediately after the collision, the master of the Oswego Guardian ordered his ship at full speed away from the scene ! Heavily damaged at the bow, she was escorted into Cape Town by the salvage tug Arctic for drydocking.
 
 
 
 


 

John Cassels
16th August 2011, 05:40 PM
That's the incident David. I purposly refrained from mentioning names.

What you also could have mentioned that they hit bow to port side showing that they had eventually
steered into each other. The ironic thing is ; if both had done absolutly nothing , they would have
cleared each other.

Captain Kong
16th August 2011, 06:46 PM
Another one I remember was the VENPET and VENOIL, two sisiters, of 300,000 tons each, one full load 300,000, and one in ballast, They collided off Plettenberg Bay on the Cape Coast. One big collision was that 600,000 tons, BANG.
Again in thick fog, another Radar assisted collision.this was in December 1977.
they set on fire but it soon went out due to the inert gas system. A few crewmen were killed. Both tankers were abandoned,
I remember Court Helicopters, who I was flying with out of Cape Town the year previous, 1976, took a lawyer with them and claimed Salvage, I believe they copt for a few quid for that.
Wish I had been with them then.

Tony Wilding
16th August 2011, 07:54 PM
Could not get much bigger than that, the closest shave i had was when on mv wanstead, off canada in thick fog 1961, could hear a ships siren, getting closer, we stopped our engine, i suppose to listen for other ships engine, suddenly it loomed out of the fog , not going slow a ships length away accross our bows, dont know if we had radar, ? Tony wilding.

Gulliver
16th August 2011, 08:00 PM
Another one I remember was the VENPET and VENOIL, two sisiters, of 300,000 tons each, one full load 300,000, and one in ballast, They collided off Plettenberg Bay on the Cape Coast. One big collision was that 600,000 tons, BANG.
Again in thick fog, another Radar assisted collision.this was in December 1977.
they set on fire but it soon went out due to the inert gas system. A few crewmen were killed. Both tankers were abandoned,
I remember Court Helicopters, who I was flying with out of Cape Town the year previous, 1976, took a lawyer with them and claimed Salvage, I believe they copt for a few quid for that.
Wish I had been with them then.


Thanks for that Brian.

More details then:

VENOIL16.12.77 Kharg Island to Nova Scotia with crude oil.(2* killed in explosion after collision with sister VENPET .Remaining crew picked up by helicopter and P &O bulk carrier Jedforest.
Cargo transhipped onwards to Nova Scotia by Litiopa(Shell(Bermuda)
Repaired at Sasebo
Broken Up Ulsan 15.1.84
VENPET
16.12.77 in ballast Nova Scotia to Kharg Island.Collision with VENOIL , 22 MILES off Port Elizabeth.Crew rescued by Clan Menzies.
Repaired at Nagasaki.
1980 named ALEXANDER THE GREAT
6/1984 Hit by Iraqi Exocet missile in Gulf(Kharg Island).Broken up Kaohsiung 6.10.84
 
Interesting eventual fate of the VENPET IN 1984 !

I think the collision is mentioned in the Guinness Book of Records? ?…. something like the greatest mass (450,000 tonnes) involved in a collision by 2 man-made objects?

I believe they were passing each other at close range to get a better view for the crews on each other. Perhaps the Captains wanted to shake hands?….. A very expensive and tragic handshake it turned out to be.
Gulliver

Arthur John Harvey
31st August 2011, 01:00 PM
R235941 None of the ships I served on during the war had radar; but some of the RN ships were so equipped,however, the Queens Mary and Elizabeth were equipped with the Admiralty 261 or 281. Being one of the old school when I took my radar certificate in 1947 with revisions at a later date, we where told that when you changed course ensure it was six points as within ten minutes such a large alteration clearly indicated your movement; as at that time I was on cross channel service to the islands it was frequently necessary with channel traffic. Recall when I was bringing a naval reserve inshore sweeper back from the continent to Hull, all our power failed and we were in dense fog; however we still had a battery echo sounder working along with a magnetic compass. I asked for some tracing paper and there was a silence on the bridge wondering ‘what the hell is that for’; when I plotted a line of soundings onto the paper and then lined it up on the chart all were surprised. Needless to say we made the Humber by the old fashion method of identifying fogs signals.

captain gordon whittaker
31st August 2011, 02:21 PM
We had a radar on the "Arabia" in 1958, but it was locked in a wooden cupboard, and the key kept by the Master, who did not hold with these "New-fangled" gadgets. It was never used so we always obeyed the Colregs to the letter, aand sounded fog signals, after doubling lookouts. Watches doubled for several days, sometimes. (2 hours before watch & 2 hours after. 8 hours in all). Apprentices almost lived on the Bridge.

Capt Bill Davies
31st August 2011, 02:44 PM
Gordon,
There were a few Masters in the BF who were a little apprehensive in their embrace of new technology. Many only used the Radar at night, when the vessel was in hand steering. Iron Mike was off at sunset. Watches were doubled up in the Irish Sea. There was no end to it.

Bill