Can you identify this instrument
Gender Faculty Specialist
This is the closest image I can find, obviously in a more modern guise.
http://www.ebay.com/itm/Datamarine-W...-/141701150055
http://www.ebay.com/itm/Datamarine-W...-/141701150055
Clunk, you clearly haven't bothered to read my previous post, have you? Does someone providing a wrong answer automatically equip you with the correct one? If so it is you who can enlighten us as I have no such supernatural ability.
It is obviously not a wind instrument as they display through 360degrees, as does the one in Morgan's link that shows little resemblance to the indicator in question.
There is no indication it is "missing some markings" that I can see. I see nothing in it's condition to suggest the total obliteration of one whole section of the markings. imo the "missing" markings were never there as there is no indication to think otherwise.
This sentence fails in both sailing technical reality as well as logic. If you can't sail within 20 25 degrees (he! he! he! wanna job designing the world's highest performance sailing boat, cos none gets close to those figures?) then why annotate the dead zone so accurately when it doesn't need annotating at all?
What sort of sailing craft is this that can only use wind up to 60' off the bow on one tack but all the way to a dead run on the other? Some kind of asymmetric proa gunboat perhaps? Did the War Department/MOD ever have any of those?
What sort of military sailing vessel ever used WWII clockwork instruments for heaven's sake? Historically impossible, I'm afraid.
Shouldn't we try to keep this interesting discussion within the realms of reality??
It is obviously not a wind instrument as they display through 360degrees, as does the one in Morgan's link that shows little resemblance to the indicator in question.
There is no indication it is "missing some markings" that I can see. I see nothing in it's condition to suggest the total obliteration of one whole section of the markings. imo the "missing" markings were never there as there is no indication to think otherwise.
The reason the 30-0 sections are marked in single degrees is because you can't sail much closer to the wind than 20-25 degrees,
What sort of sailing craft is this that can only use wind up to 60' off the bow on one tack but all the way to a dead run on the other? Some kind of asymmetric proa gunboat perhaps? Did the War Department/MOD ever have any of those?
What sort of military sailing vessel ever used WWII clockwork instruments for heaven's sake? Historically impossible, I'm afraid.
Shouldn't we try to keep this interesting discussion within the realms of reality??
Last edited by Wageslave; 22nd Nov 2015 at 15:33.
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"Mushroom induced", as chief pilot for my corporation I find this sort of remark offensive to level at a pilot say the least, I sugest you withdraw such comments and try not to be so offensive on what should be an interesting and hopefully polite discusion. Now back to the question, WHAT IS IT? I just had a look at firing arc limiters on various WW2 aircraft but they used simple rods sticking up to prevent one shooting ones own aircraft down or interupter systems on the gun itself, I will be visiting an ex air gunner next week, he might know as he flew as crew on everthing from Hampdens to B17s, the B29 had an interesting system to prevent friendly fire damage but I dont recall anything like this on the B50/B29s when used as tankers, so it looks like it was most likely a shipboard thingy.
Last edited by clunckdriver; 22nd Nov 2015 at 16:14.
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I didn't say you couldn't sail within 20-25 degrees I said you can't sail much closer than that to the wind depending on what you're sailing. Perhaps the markings are used to high light the zone.
I'm pretty sure the instrument in question won't have been fitted to a high performance racing yacht either.
There is quite obviously some sort of corrosion on the lower left quadrant not apparent on the other three quadrants.
Err, because it's a wind indicator and they display through 360 degrees. I think someone mentioned that earlier.
Naval artillery uses milli rads.
I'm pretty sure the instrument in question won't have been fitted to a high performance racing yacht either.
There is quite obviously some sort of corrosion on the lower left quadrant not apparent on the other three quadrants.
then why annotate the dead zone so accurately when it doesn't need annotating at all?
Naval artillery uses milli rads.
Morgan, there are precious few modern sailing boats that can sail inside 40 degrees off the wind so there is no point whatsoever annotating that area on a wind gauge as you simply can't go there. In any case wind indicators are so imprecise such accurate markings would be a bit superfluous. No military sailing vessel would ever have had such a gauge, there is almost a century between such technologies. Such a connection is, as I tried to allude, overly fanciful. How many more reasons do we need for this to be nothing to do with sailing?
I can see no evidence of such extraordinarily selective corrosion that might explain 2/3 of one side being surgically removed - corrosion just doesn't work like that and as it is presumably behind a glass face it probably hasn't been removed physically. As you say wind indicators operate through 360deg, this one appears to be asymmetric.
Millirads; granted, so it's probably not naval artillery.
Still none the wiser.
I can see no evidence of such extraordinarily selective corrosion that might explain 2/3 of one side being surgically removed - corrosion just doesn't work like that and as it is presumably behind a glass face it probably hasn't been removed physically. As you say wind indicators operate through 360deg, this one appears to be asymmetric.
Millirads; granted, so it's probably not naval artillery.
Still none the wiser.
G
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PingDit,
SARBE Directional Indicators have 360 degree coverage. I think Genghis's idea of a Carrier Wind over Deck Indicator or Repeater has merit as the indication would be asymmetrical as the Island would make one side effectively unusable.
SARBE Directional Indicators have 360 degree coverage. I think Genghis's idea of a Carrier Wind over Deck Indicator or Repeater has merit as the indication would be asymmetrical as the Island would make one side effectively unusable.
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That would depend where the wind vane was positioned.
But you'd want a wind over deck indicator to register through 360' and you'd position it at the masthead where it would be unobstructed.
The big clue is that missing sector. What and why?
What did ASDIC repeaters for depth charge/hedgehog attack look like? Were they ever fitted with one on each side of the hull allowing a bit of crossover to the "other" side? Then 30' either side of dead would need to be accurately known for running in, but not to more than a couple of degrees and other sectors to within 10 would be fine to allow you to fire abeam.
The big clue is that missing sector. What and why?
What did ASDIC repeaters for depth charge/hedgehog attack look like? Were they ever fitted with one on each side of the hull allowing a bit of crossover to the "other" side? Then 30' either side of dead would need to be accurately known for running in, but not to more than a couple of degrees and other sectors to within 10 would be fine to allow you to fire abeam.
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The instrument is Naval, not Aeronautical and probably had an exact name at the time, but it's function is that of an azimuth ring, being part of the compass mounted in the binnacle and/or the bridge wings. Could be called azimuth ring or circle, pelorus.
That model , with the Selsyn connections would be a repeater from the main instrument, acting synchronously from the main drive.
The reason for the additional graduations (and it is not any more accurate within the -30 deg to +30deg span) is that this is the usual convention between normal to emergency Hard to Port/Starboard. The 30 to 180 degree markings spans simply complete the circle but for the helmsman the span of interest and response time would relate to the +/- 30 degrees of lubbers line.
These extracts from Admiralty Seamanship Manuals put it in perspective.
A Seamans Pocket Book June 1943 / HMSO / by Authority of the Lords Commissioners of the Admiralty / BR 827
"The amount of rudder carried by a ship is always turned over by the helmsman to his relief.
The man at the wheel may or may not be in a position to see where he is going. Some steering positions are situated below, under armour. In a small ship, however, he will usually be able to see ahead, and if in company with other ships may be ordered to "follow the next ahead". In this case he will steer in her wake, using as little wheel as possible and keeping her masts, etc, in line with his own ship's stem. He must at all times be ready at the order "Steady!" to disregard next ahead and steer by compass.
The helmsman always repeats all orders exactly as heard and reports when he has carried them out. The order "Hard a port" or "Hard a starboard" (i.e. 35 degrees of rudder) is only given in an emergency. The normal order would be "Port 30", etc. Never force the wheel over. If it jams or gets stiff inform the quartermaster, who will tell the officer of the watch. The helmsman's duty is to steer the ship under the supervision of the quartermaster. He is relieved every two hours, and on being relieved must inform his relief what the course is and what 'rudder' the ship is carrying. This two-hour turn of duty is called a 'trick.' "
The 1995 Admiralty version of Manual of Seamanship is somewhat updated but still refers;
"10020. Manual Steering Conning Orders
a. Wheel Orders
These are conning orders to put the rudder over in a given direction to a particular angle, eg 'STARBOARD TWENTY'. Wheel orders are given by the Captain or OOW when the ship wishes either to start altering to a given course, or to control the heading of a ship when no course has been ordered. On receiving a wheel order, the helmsman repeats the order and turns the handlebar or wheel in the required direction to the angle shown on the wheel indicator on the Quartermaster's Console. When this has been done, he reports that the amount of wheel ordered is 'on', eg TWENTY OF STARBOARD, ON'.
b. Altering Course.
To alter course by more than 20 deg, the Officer of the Watch starts by giving a wheel order, and follows this by telling the helmsman the new course to which the ship is turning, eg. 'STARBOARD TWENTY, ALTERING 340DEG'. The helmsman acknowledges by repeating the order and reports the rudder angle set, eg. 'STARBOARD TWENTY, ON'. As the lubbers line passes through a heading 15deg before the new course, the helmsman reports to the OOW, eg. 'PASSING 325'. From this point, the Officer of the Watch cons the ship on to the new course, first by easing the helm as she approaches it, eg. EASE TO TEN', and then by taking the swing off with opposite wheel, eg. 'PORT TEN'. Finally, when on or near the new heading shown by the lubbers line when the order 'STEADY' is given unless the Officer of the Watch gives him another course to it to steer, eg. "STEER 342 DEGREES'.
c. Small Alterations of Course
When making a small alteration of course up to 10deg, the OOW will give a wheel order followed by the course required to steer, eg. 'STARBOARD FIFTEEN, STEER 312 DEGREES'. The helmsman repeats this, brings the ship to the course ordered and, when steady on the new course, reports: eg. 'COURSE 312 DEGREES'. "
That model , with the Selsyn connections would be a repeater from the main instrument, acting synchronously from the main drive.
The reason for the additional graduations (and it is not any more accurate within the -30 deg to +30deg span) is that this is the usual convention between normal to emergency Hard to Port/Starboard. The 30 to 180 degree markings spans simply complete the circle but for the helmsman the span of interest and response time would relate to the +/- 30 degrees of lubbers line.
These extracts from Admiralty Seamanship Manuals put it in perspective.
A Seamans Pocket Book June 1943 / HMSO / by Authority of the Lords Commissioners of the Admiralty / BR 827
"The amount of rudder carried by a ship is always turned over by the helmsman to his relief.
The man at the wheel may or may not be in a position to see where he is going. Some steering positions are situated below, under armour. In a small ship, however, he will usually be able to see ahead, and if in company with other ships may be ordered to "follow the next ahead". In this case he will steer in her wake, using as little wheel as possible and keeping her masts, etc, in line with his own ship's stem. He must at all times be ready at the order "Steady!" to disregard next ahead and steer by compass.
The helmsman always repeats all orders exactly as heard and reports when he has carried them out. The order "Hard a port" or "Hard a starboard" (i.e. 35 degrees of rudder) is only given in an emergency. The normal order would be "Port 30", etc. Never force the wheel over. If it jams or gets stiff inform the quartermaster, who will tell the officer of the watch. The helmsman's duty is to steer the ship under the supervision of the quartermaster. He is relieved every two hours, and on being relieved must inform his relief what the course is and what 'rudder' the ship is carrying. This two-hour turn of duty is called a 'trick.' "
The 1995 Admiralty version of Manual of Seamanship is somewhat updated but still refers;
"10020. Manual Steering Conning Orders
a. Wheel Orders
These are conning orders to put the rudder over in a given direction to a particular angle, eg 'STARBOARD TWENTY'. Wheel orders are given by the Captain or OOW when the ship wishes either to start altering to a given course, or to control the heading of a ship when no course has been ordered. On receiving a wheel order, the helmsman repeats the order and turns the handlebar or wheel in the required direction to the angle shown on the wheel indicator on the Quartermaster's Console. When this has been done, he reports that the amount of wheel ordered is 'on', eg TWENTY OF STARBOARD, ON'.
b. Altering Course.
To alter course by more than 20 deg, the Officer of the Watch starts by giving a wheel order, and follows this by telling the helmsman the new course to which the ship is turning, eg. 'STARBOARD TWENTY, ALTERING 340DEG'. The helmsman acknowledges by repeating the order and reports the rudder angle set, eg. 'STARBOARD TWENTY, ON'. As the lubbers line passes through a heading 15deg before the new course, the helmsman reports to the OOW, eg. 'PASSING 325'. From this point, the Officer of the Watch cons the ship on to the new course, first by easing the helm as she approaches it, eg. EASE TO TEN', and then by taking the swing off with opposite wheel, eg. 'PORT TEN'. Finally, when on or near the new heading shown by the lubbers line when the order 'STEADY' is given unless the Officer of the Watch gives him another course to it to steer, eg. "STEER 342 DEGREES'.
c. Small Alterations of Course
When making a small alteration of course up to 10deg, the OOW will give a wheel order followed by the course required to steer, eg. 'STARBOARD FIFTEEN, STEER 312 DEGREES'. The helmsman repeats this, brings the ship to the course ordered and, when steady on the new course, reports: eg. 'COURSE 312 DEGREES'. "
I'm afraid I can't see how OzBob's explanation has anything to do with the item.
A compass repeater or a pelorus (totally different instruments) both need to cover the whole 360 degrees and would be graduated in degrees all the way around, they'd be useless with less accurate reading possible.
Quite how those helmsman's orders and procedures link to the item is beyond me, I can see no correlation at all and least of all how applying 20 or 30 degrees of rudder relates to graduations on a compass repeater.
Any more ideas?
A compass repeater or a pelorus (totally different instruments) both need to cover the whole 360 degrees and would be graduated in degrees all the way around, they'd be useless with less accurate reading possible.
Quite how those helmsman's orders and procedures link to the item is beyond me, I can see no correlation at all and least of all how applying 20 or 30 degrees of rudder relates to graduations on a compass repeater.
Any more ideas?
"Mildly" Eccentric Stardriver
From what little I can find reference wind indicators on carriers, could it be a repeater from Flyco to the deck, perhaps to the batsman?