Radar question for merchant mariners

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absit_omen

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After quite a few drinks yesterday a mate of mine (ex MN) said that many large ships switch off their radars when in deep sea. He claimed that this was because some radars were hired and were billed on hours used. Is this correct or just alcohol fuelled tosh?
 
A friend did the ARC in 2001 saw a ship coming over the horizon towards them. He managed to raise them on VHF to which their reply was "We will turn our radar to see if we can see you" or words to that effect.

Don't know anything about the charging aspects though.
 
Always had ours off, except for low viz conditions. But that was a few years ago and practices change.
Was on the bridge of the Val de Loire recently and a sailing schools Sigma 38's were totally invisble on the fantastic radar set at approx 2 miles - despite being being highly visible to the naked eye - worrying thought.
 
merchant mariner

Have a look at rule 5

Effective lookout by what ever means possible - includes radar

I've never heard of radar being charged for by the running hours.

I've been on ships going from gulf to gulf, radar on all the time.

Maybe the ship you spoke to was switching between long and short pulse. (different ranges).

JMHO
 
Definitely used to be common practise some years ago but because the power valves had a finite life.

Rule 5? Yes, well we should all stick to the speed limits too.
 
Until 20 yrs ago this may have been standard practice due to reliability problems.
Although I still see the odd ship nowadays with no radar running.
On the ships I've been on in last 20yrs, all have had at least one radar running. In fact we use the radars in all weather conditions good and bad. Operators gain experience and familiarity in ideal conditions so that in poor vis, can interpret and have confidence in the equipment. The radars are now our main navigation tool and only second to the compass &/or gyro.
Ultimately though you can't beat the human eye for picking up small targets. Yachts are notoriously difficult to detect by radar. Will often see a yacht visually long before it is detected by radar (if at all).
 
" Definitely used to be common practise some years ago but because the power valves had a finite life."

I have always been led to believe that valves are more reliable if left with power on, very rarely fail if not switched on and off.

Or maybe those valves were over driven - which can change things a bit.

I once melted the glass on a valve - which is sort of fun - but expensive - cost abou 15 squids and that was many years ago

Rambles off muttering into beard
 
Have only served on survey ships, ours were always on. When doing paperwork at the after end of the bridge, the oow could still maintain a radar watch.

Magnetrons wear out with use, giving a radar set a finite life until replacement required.

I can imagine that there are enterprising companies offering a bridge intstrument fit and maintenance service though this was never my department.

Which doesn't add much really, but it's nice to visit the forum from time to time.
 
When I was a humble deckhand the mate had his head stuck in the radar and rarely looked out the widow,so he missed several ships,looking out the window wasnot scientific enough.One of the dutch owners came for a trip and said the radar was good as his ships could maintain full speed in fog!
 
Generally we had the radars on the go at all times. Although on a dark night they can give out quite a bit of back-light and maybe some OOW's will switch them down or even off for this reason? Having said that, I did sail with one old man who always turned the 10cm off when "over the horizon" as he wanted his watch keepers to look out the window instead...
 
It used to be common for Masters to have Radars switched off once deep sea ... but as far as I know the preactice diminshed and most ships that we deal with leave them running .... except when in port - as it is required on tankers to switch / isolate all electrical stuff such as Radio / radar systems.

As to billed hours - never heard that at all ....

Masters excuse often was to save the Magnetrons ands screens .... and I even had one master when I was 3rd mate reckon to swoitch off - to stop us becoming "radar-babies" - that vessel we nearly had collision of West Africa ... due to the policy.
 
And another answer

I agree with the other posters.

The reason was that early radars had cathode ray tubes with screens that were easily damaged. In particular, it was possible to burn holes in the CRT screen, which of course gave you a blind spot. So the wonderful new gadget was kept for when it was most needed

In the company I worked for there was once an epic row between the Technical Department (engineers!) who were worried about the cost of replacement CRTs and issued a Fleet Circular saying that CRTs should not be replaced just because there were a couple of burned spots on the screen, and the Marine Superintendent, who had litters of kittens at the thought of the collisions that would result.

The last case that I can recall of a collision caused by both the radars being off involved a large new and very splendid cruise ship in the early 90's. The officers were Italian. The Master was of the Old School and ordered the radars off in good visibility. One fine calm starry night whilst making 18 knots she ran down and sank a Cuban tanker that was lying dead ship and showing no lights. The two watchkeeping officers (big cruise ship!) were exonerated because by good fortune a lady passenger had had a row with her boyfriend in the disco and had gone out on deck for some fresh air; she saw the "dead ship" tanker moments, before impact and could confirm that it was showing no lights.
 
Re: And another answer

[ QUOTE ]
........ a lady passenger had had a row with her boyfriend in the disco and had gone out on deck for some fresh air; ......

[/ QUOTE ]

Don't tell me - she met some young traveller from the lower decks who gave a seeing to in an old car in the hold, then after the collision dropped her necklace over the stern ! /forums/images/graemlins/smile.gif
 
take it from me - its a load of bolloxs, however in the 60's and 70's I came accross ships where the radar was locked up and the key held by the master, to turn it on meant calling him, and the r/o, and getting the thing flashed up ...... took about 30 mins ......

nowadays (with iso regs etc ..) radars are used as part of the bridge anti collision/nav gear, at least one on during the day and 2 at night - even deep sea.

in accordance with my masters standing orders anyway. /forums/images/graemlins/cool.gif
 
Re: And another answer

The tanker was smaller than the cruise ship, which was one of the big white jobs.

The tanker just rolled under the flare of the passenger ship's bow, crumpling it a bit, but not that much, rolled, and sank immediately. So her crew didn't get to remember anything. Nobody was hurt aboard the big white job.
 
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