May 23/24 night shadowing and interception approach CS1/BC1

[Dave Saxton]

@ Dave Saxton,

can you be so kind to tell me the difference between the utilization and range of those radio frequencies :

- Fleet Wave ; 138 K c/s ; 500 K c/s ; 4,740 K c/s ; 8,290 K c/s

From Battle Summary Nr. 5 on the W/T ( Wireless Transmission ) chapter :

Royal_Navy_radio_frequencies.jpg

Especially about the 138 K c/s W/T frequency specifications, because from Capt. Leach report we can read :

... at 23.34 "Prince of Wales" was signalled to report bearing of "Suffolk" by D/F on 138 Kc/s.

So, if I read correctly between PoW and Hood at " short " distance thay could break the " radio silence " as it seems clear to me, ... surely NOT being intercepted and NOT reaching Scapa or Iceland from where they could have listen to them and record those messages ( including the enemy ), ... and in fact it did NOT happen ... since we have NO evidence of those transmission that occurred in reality between PoW and Hood ...

If I am right, ... as I think looking at those evidences, ... this means that most likely many other Royal Navy units when at close distance each others could use this W/T ( Wireless Transmission ) method too ... even if under " radio silence " officially ... and now I think about those 4 destroyers up there ...

Bye Antonio

The frequencies listed are not those used by short range radio such as talk between ships. These are long range radio frequencies. ( I think 500 kilos is the international marine emergency wave length of 600 meters) If they had to relay the messages from ship to ship it was because things were not working properly. Perhaps there was "atmospherics" or antenna icing or something. Didn't Bismarck's radios also have a hard time getting out as well?

The Allie's TBS frequencies were in the VHF range of 30 to 300 mega cycles. The frequencies listed are are in the medium to high frequency bands of 300 to 30000 kilo cycles. These would not be used as a secure means to communicate over short distances between RN warships. They would use their VHF equipment for that. VHF was line of sight.

FWIW, The German Navy used both VHF (which they called UKW ) and UHF bands for tbs radio.

[Antonio Bonomi]

Hello everybody,

@ Dave Saxton,

thanks Dave, ... that is what I was suspecting but I wanted to be sure about it, ... so, Capt. Leach statement must be read being a request from Hood to PoW to tell them the D/F bearing interception of the Suffolk transmission using the 138 K c/s radio wireless frequency, ... and NOT to transmit from PoW to Hood those Suffolk D/F information/data using the 138 K c/s frequency.

Can you tell me a bit more about those TBS ( Talk Between Ships ) equipment :

The Allie's TBS frequencies were in the VHF range of 30 to 300 mega cycles. The frequencies listed are are in the medium to high frequency bands of 300 to 30000 kilo cycles. These would not be used as a secure means to communicate over short distances between RN warships. They would use their VHF equipment for that. VHF was line of sight.

https://books.google.it/books?id=RBC2nY ... es&f=false

viewtopic.php?t=5814

World War II-era TBS radios were basically low-powered, 50 watt, line-of-sight devices so that the enemy couldn’t pick up and DF (direction find) on the signals. They could be tuned to operate on any frequency in the 60 to 80 MHz range, the frequency being fixed and controlled by the use of crystals. They had an effective range of about 10 miles.

There were eight models in the series, TBS-1 through TBS-8. All were manufactured between 1938 and 1945 by the RCA Corp. except TBS-4 and TBS-7, which were produced by General Electric. As far as features and functions were concerned, they could transmit and receive either voice or CW (Morse Code) and that was about it. They could accommodate up to two remote control units; however, these weighed about 10 pounds each and had to be fix mounted—check out the photo at right.

Taken from here :

http://www.marineelectronicsjournal.com ... =VIEW&a=92

Do you think both on Hood and PoW, as well as on the 2 heavy cruisers and the 6 destroyers that night they had those equipment available to be used ?

Thanks and bye, Antonio

[wadinga]

Hello Dave and Antonio,

I have never seen any suggestion that TBS style equipment was available. We know PoW and Hood had problems even with the W/T gunnery net, and executive- vitally important- messages for squadron manoeuvring were done with flags. (In 1941 ) We don't know for sure instructions were given to the destroyers by Aldis lamp but it seems likely.

We know communication with the Coastal Command aircraft was very likely done the same way.

It seems unlikely that the FBI are going to find a lot of incriminating e mails in Wake-Walker's account That is these are all secure methods of communication. Brinkmann observes that VHF voice calls between ships are insecure.

On M/F-D/F this article suggests + or - 2 degrees is exagerrated poor performance http://nvlpubs.nist.gov/nistpubs/Scient ... 29_A2b.pdf however these are for continuously transmitting nav beacons not a 30 sec transmission. See p 564

M/F D/F bearings to Norfolk and later Suffolk are clearly indicated on original PoW track plot and there are none after 03:38. The 05:41 positions are PoW's guessed DR for invisible cruisers.

The "Game" is not over it is afoot!

All the best

wadinga

[Dave Saxton]

I don't know if Hood and POW had VHF equipment, but think it likely since RCN destroyers did starting from 1938. Nonetheless, I agree that they would likely use signal flags and/or lamps for those situations. The frequencies are given for the recorded messages and they are MF and HF bands, not VHF.

[Antonio Bonomi]

Hello everybody,

@ Dave Saxton,

many thanks, ... my request was mainly directed to realize how the 4 Royal Navy destroyers could have been re-grouping after they divided themselves that morning, ...

Their distance was in the range of 15 sea miles, ... and after 3 am there was enough light, ....

Can you confirm that in case of a VHF message TBS type, those were NOT going to be recorded in any circumstance ?

What was the common practice ?

@ Wadinga,

thanks for your confirmation about how the Royal Navy warships in squadron communicate each others on 1941.

As obvious I was mainly interested on how the destroyers could communicate each others that morning, ... but it is always good to know as much as we can also for the other Royal Navy units, ... including the aircrafts, ... you never know future needs ...

I will NOT intentionally comment anymore on RearAdm W.F. Wake-Walker. The reality everybody can easily realize is more than enough by itself.

Some degrees of bearing as well as few sea miles tolerance must be taken in consideration given the level of information we have available at hand.

The bearings I have used to nail down forever the Norfolk track are the most precise available in this moment, ... taken from the PoW map as well as from he Norfolk own strategical map ( at 05.41 vs Suffolk ). It is a grid of bearings fixing the 05.41 point and you know it from the PoW Polygon from Plan 4 plus F.O. Busch book ones. The Norfolk own 05.41 strategical map bearing to Suffolk ( 320° = D/6 or D/C on The Plot ) is just perfectly matching with them resolving the matter forever.

Now the overall map is connected with the " PoW Plan 4 Polygon ", ... with the battle map, ... and with the corrected version of " The Plot ".

Based on the above, for me the " game is over " about how to position the Norfolk own track from 02.29 until 05.41.

But, if you find a new set of more precise and reliable information, ... and you will be able to put them together in a comparable way matching them all as I did, ... I will really love to re-open the " game " between us on this matter.

Bye Antonio

[Cag]

Hi All

There is quite a good website at RN museum of radar and communications (HMS Collingwood) which has lots of info. It gives radar and wireless equipment designations fitted to ships and dates etc when m/f d/f became h/f d/f (h/f d/f was not available to PoW etc iirc) and such like although Mr Saxon is most definitely your best source for such things.

There is also jproc.ca I believe giving details of Canadian wireless fitments to ships which is another source.

Hope this helps
Best wishes
Cag

[Alberto Virtuani]

Hi all,
one additional maneuver that puzzles me is the one Capt.Leach refers to in his narrative at point 10:

04_50.jpg (25.91 KiB) Viewed 1117 times

Assuming all the previous course changes were done together as per Leach account (by blue pendant = "a un tempo" in Italian, if I have understood correctly from Paul Cadogan) the Hood should still have PoW on bearing 90° (as it was at 23:15) while sailing on course 240°at 04:50. Therefore Hood was ahead at this point in time.

Reading Capt.Leach there is no detail on how PoW took "guide" of the fleet but he says Hood was stationed at the same time on bearing 230°, that, while sailing on 240°, is still well ahead of the PoW . Therefore I don't understand how Hood could take the lead again at 05:05.....

Is anybody able to explain what should have been the maneuver in this timeframe ?
Could Leach have mixed up the Hood bearing with the PoW one (as PoW at 230° from Hood would have made her "guide") ?


Bye, Alberto

[Dave Saxton]

Hello everybody,

@ Dave Saxton,

many thanks, ... my request was mainly directed to realize how the 4 Royal Navy destroyers could have been re-grouping after they divided themselves that morning, ...

Their distance was in the range of 15 sea miles, ... and after 3 am there was enough light, ....

Can you confirm that in case of a VHF message TBS type, those were NOT going to be recorded in any circumstance ?

What was the common practice ?

I don't know if any VHF or other vocal messages would have been recorded or not. I have not seen any such RN transcripts from this operation.

Normally the max range for the Allie's VHF tbs equipment is listed as 10 nautical miles.

The USN used tbs equipment extensively during the night battles in the Solomon Islands. Were these vocal messages and chatter recorded word for word or just remembered after the fact? During the heat of combat it was probably not possible to keep up. Did the RN procedures differ from USN practice?

In the case of the Scharnhorst and German destroyers at North Cape, survivors claimed that Scharnhorst was communicating with a destroyer or Johannesson's destroyer group via tbs in the minutes just before the first skirmish. These communications remained undetected by the enemy. I don't know if there are records of these communications among the destroyer's records. The range was far greater than 15 miles to the main group of German destroyers from the Scharnorst by then. However, communications among the destroyer group were taking place as well.

There was one exception. Z33 was operating independently trying to rejoin with the Scharnhorst. It may have been within 15 miles from the Scharnhorst at that time. A second pip was indicated on Belfast's radar 24,000 yards from the Belfast to the North after Scharnhorst turned to the South and increased speed. This may have been Z33. Nevertheless, we don't know if Allied tbs equipment was analogous to German equipment in terms of range or if the transmitting and receiving conditions were similar.

[dunmunro]

Hello Dave and Antonio,

I have never seen any suggestion that TBS style equipment was available. We know PoW and Hood had problems even with the W/T gunnery net, and executive- vitally important- messages for squadron manoeuvring were done with flags. (In 1941 ) We don't know for sure instructions were given to the destroyers by Aldis lamp but it seems likely.

We know communication with the Coastal Command aircraft was very likely done the same way.

It seems unlikely that the FBI are going to find a lot of incriminating e mails in Wake-Walker's account That is these are all secure methods of communication. Brinkmann observes that VHF voice calls between ships are insecure.

On M/F-D/F this article suggests + or - 2 degrees is exagerrated poor performance http://nvlpubs.nist.gov/nistpubs/Scient ... 29_A2b.pdf however these are for continuously transmitting nav beacons not a 30 sec transmission. See p 564

M/F D/F bearings to Norfolk and later Suffolk are clearly indicated on original PoW track plot and there are none after 03:38. The 05:41 positions are PoW's guessed DR for invisible cruisers.

The "Game" is not over it is afoot!

All the best

wadinga

TBS did not become common in the RN until supplied with TBS units via lendlease. AFAIK, the only RN units capable of voice communication were those ships equipped for fighter direction and this was usually restricted to communicating with FAA or Coastal Command fighter aircraft.

[Cag]

Hi All

Hi Alberto, I think the term taking over guide of the fleet simply means that the role of keeping the 'fleet' on a bearing on which the senior officer required it to be on would have been the sole responsibility of PoW navigation officer and helmsman instead of that of those men on Hood. Up to that point the responsibility of Rowell and the helmsman was keeping station with Hood and recording course etc. I'm not sure its necessary for the ship maintaining the guide to be ahead if the other ship is doing something other than being the guide.

What Hood was doing on course 230° as you say is not mentioned nor is her distance from PoW but I presume it was something other than fleet navigation (something to do with gunnery or attempting to d/f or equipment calibration?). This was completed by 05.05 and Hood resumed guide or relieved PoW allowing her to continue to keep station.

Best wishes
Cag.

[Antonio Bonomi]

Hello everybody,

@ Dave Saxton

many thansk for your very precious information about the radio communication possibilities ...

@ Dunmunro,

I see your inputs about TBS not being used on 1941 at least, ... so according to your opinion how were the destroyers communicating each others from the separation until they decided to come back ...

@ Alberto Virtuani,

a very good and interesting question ...

@ CAG,

if that is true, ... then it will be interesting to try to realize what they did on Hood on that timeframe, ... and what happened soon after that event on Hood ...

Bye Antonio

[paulcadogan]

Is anybody able to explain what should have been the maneuver in this timeframe ?

Hi Alberto,

I think I figured that out when we were discussing Antonio's track chart for the 160 degree turn to the south west at 0203. It was by Blue Pendant with PoW initially bearing 90 deg from Hood - i.e. on her starboard beam. After the turn, Hood would have been slightly ahead on PoW's starboard side as Antonio illustrated.



With the other turns to 220 and then to 240 also by Blue Pendant,PoW would have fallen further astern of Hood, with Hood remaining on her STARBOARD bow.

With the Germans expected to appear on the starboard side, it could have been problematic if Hood was to starboard of PoW - her funnel smoke, if not Hood herself would interfere with PoW's line of sight to the enemy. It was therefore necessary for Hood to move to PoW's PORT bow so both British ships could have an unimpeded view of the enemy. If Hood remained "guide" the PoW was obliged to conform to her movements, so in order for Hood to change her position, PoW was made "guide" - i.e. she maintained the squadron's course, allowing Hood to alter course - most likely to fall behind, cross astern from starboard to port, then either Hood speeds up to retake her lead position, now on PoW's PORT bow resuming guide, or PoW would take her foot off the gas to again retake her station, now 4 cables on Hood's starboard quarter. The process took 15 minutes - 0450-0505.

This is why I said previously that those last photo's of Hood taken from PoW, if they were taken on May 24, were probably taken between 0505 and 0535...





But the obvious question would be, why not let Hood remain guide and let PoW change her station? I suspect the answer might be speed. PoW was already behind, and altering from Hood's port to starboard quarter would have made her fall further behind, having a harder time to regain her station.

I suppose it could have been done either way, but obviously Holland chose to move Hood.

Paul

[Alberto Virtuani]

@Mr.Cag and @ Paul Cadogan,

thanks a lot for clarifyng the meaning of the term "take guide".
I think you can be right saying that this doesn't mean necessarily to be "ahead".

I also agree with Paul analysis of the reasons why Holland decided to do that (to allow Hood to move on the PoW port side and this also confirms that Holland was already aware (and in full control) of the interception geometry to come shortly.

I would just tend to say that, IMHO, Hood did not fall behind PoW to do this maneuver, as she was already in front of the PoW and to issue the order to "take guide", to slow down, to pass behind PoW "circling around her, then to recover the lead and finally to issue the order that Hood was resuming the lead , while sailing already at 28 knots, would have taken more time than 15 minutes and would have been a much more difficult maneuver to execute, loosing time and precious geometry.

I would imagine Hood was just moving from PoW starboard side to port while remaining ahead of the latter (as Leach words suggest, not mentioning the "circle" around his ship but just saying that Hood "stationed herself on 230° bearing" from the previous 270°)


Bye, Alberto

[Cag]

Hi All

If it is ok may I ask a question. I am sure that you are correct as regards what occurred and bow to greater knowledge but I'm a little unsure on a couple of things.

I've re read my old RN seamanship manuals and it does state that if a ship has been stationed at a point then if a turn is ordered the ship executing that turn and the ship following must modify their speeds to maintain their relative stations. Therefore if PoW was to starboard of Hood when travelling on the bearing 000° then she would be to starboard after the turn to 200° or not?

Obviously if the stationing order was cancelled or altered or the signal to turn was specific ie both ships turn together or in order etc etc. I am of the opinion that we may not know for sure exactly what occurred only that a turn was ordered.

I do know that a turn to starboard is shown by the turn flag followed on the halyard by the numeral of the turn ie turn starboard 50° would be turn flag (BT would be the turn flag if turning together) and numeral 5. A turn to port would be the numeral flag first then the turn flag.

Also on the pics posted by Mr Cadogan of Hood taken from PoW, is it possible to narrow down when these were taken by studying when battle flags were hoisted as I believe Leach puts this at 00.15 on the 24th. I may be wrong but I can't see the large battle flags flying in the image of Hood just the small one always flown at the main mast gaff?

Thanks for any help
As always best wishes
Cag.

[Cag]

Hi All

Just a quick addition, is it possible that Hood being on 230° is something to do with the fire control signals made prior to the Battle?

If you look at the enclosure ii of PoW gunnery report it does state that between 01.03 and 05.43 preliminary testing took place. Could this manoeuvre and handing over of the guide be something to do with this as far as Hood was concerned?

Again I doubt we will ever know for sure but it is fun trying to work it out though!

Best wishes
Cag.