1940 Convoy: Distances 'twixt columns, ships, & c. information request

This is is just to highlight a question raised twice now on the thread below:
We ( or rather, a Polish friend and I ) and the OP have done the hard bit of translating a very valuable detailed log from a Polish destroyer but I am sure the information requested is at a learned member's fingertips.

Translation of Polish naval logs required

Copy & paste:

"One issue I have not been able to find out is how Convoy H.N.25 would have been set up. I know Convoy H.N.25 formed into 4 columns with steamers with FYLINGDALE (3918grt), GLEN TILT (871grt), BRIGHTON (5359grt) and LEO (1140grt) as column leaders. There were 39-42 ships in this convoy depending on which source you use. The passage of Convoy H.N.25 took 73 hours covering a distance of 515 nautical miles between Hovden Island Point, 85 nautical miles north of Bergen, and Methil on the Firth of Forth. The convoy's average speed was 7 knots per hour.

What I can't find are details of the distance between the 4 columns and the distance between ships in those columns. This would give me an idea what sea area the convoy would have covered. I would welcome any advice from our more experienced members on what was the standard practice for merchant convoys of this type and size in April 1940.

Thanks again for your assistance. John H."

And thank you in advance from Shetland, Essex, and Poland.

 

Not sure how relevant this might be

World War II at Sea

I am sure others have more specific details for your time period

TD

World War II: The Definitive Encyclopedia and Document Collection [5 volumes]
Theres a few references in their as well

The Allied Convoy System by Arnold Hague - AbeBooks
ConvoyWeb you could email them and ask the question

 

It would seem that specific Admiralty instructions were issued for each convoy which included both the formation (number of columns etc) and the spacing and that this might vary on different legs of the voyage. Convoys could be single column, 2 columns or three columns and obviously in the case you quote four. There were convoy files at the Public Records office and I assume that these are now at TNA and can be accessed. The file for the convoy you are interested in should be there.

I enclose the details for convoy JW 51A which should provide an idea. This was a "broadfront" convoy ie 3 columns. The Admiralty instructions were 'columns to be 5 cables apart by day and night unless otherwise ordered. Ships in column to be 2 cables apart' Whilst I suspect spacing might vary depending on the specified convoy speed I wouldn't have thought by that much

 

I agree that specific instructions would be issued for each convoy and would think the spacing would depend much on whether it was a 'fast' or 'slow' convoy and the maneuverabilty of the merchantmen. Greater distance being allowed for error in a 'fast' convoy zigzagging. I should know the answer but I can't put my hand on it at the moment.
Meanwhile from Convoy rescue ship - Wikipedia
The convoy rescue ship was a response to early experience. Each merchant ship in a convoy was assigned a station so that the convoy formation would consist of several columns of three to five ships. The lead ships of the columns were spaced at intervals of 1,000 yards (910 m) along a line perpendicular to the convoy course. Each ship in the column followed the ship ahead at a distance of 800 yards (730 m).
These separation figures for columns agree with the previous post but the distance between ships is twice that, 800yds being 4 cables.

Tim
Edited to add. From HyperWar: Antisubmarine Warfare in World War II [Chapter 10]
Typical convoy disposition.

 

Thank you all for your contributions, it is very much appreciated, I am the OP for this thread.
What I can add to this discussion: Captain Pinkney reported in his Commodore Report of Convoy H.N.25 "We continued at about 7 knots, without zig-zagging..". The translation of the ORP Blyskawica (Polish Escort Destroyer) records confirmed that the 4 escorts were zig-zagging from first light till dark. ORP Blyskawica watch officer also reports "Entered 1st fighting guard" for 4 hours and then "Entered 2nd fighting guard" for 4 hours and then back to 1st for 4 hours and then to 2nd for 4 hours and so on. This was repeated over 24 hours/3 day passage of convoy. Any ideas what this means? I assume this relates to their position relative to the convoy?

Thanks for your assistance.

John H

 

4 hours = a watch - might it mean that for the duration of the convoy the crew were doing watch on watch - half the crew four hours on and four hours off watch? Not something to keep up for very long but for the 3 days a way of having the maximum number on duty at any time

 

BTW JW 51A s convoy speed was also 7 knots.
I suspect convoy configuration might also depend upon the numbers and type of escort vessel available and what the greatest perceived threat was - surface vessels, u boats or aircraft. This might explain why configurations were sometimes varied depending on which leg of the trip it was.

 

Sounds very much like what is now called 'Defence watches' a slightly relaxed state to allow time for eating and resting as opposed to 'Action Stations' when all would be closed up. In my time Defence watches were 7on 5off 5on 7off which could be maintained for long periods.

Tim

 

Thanks to all for the contributions. I did check my 1943 Admiralty Instructions and KR but could find nothing specific. My 1879 Victorian QR and Admiralty Instructions have a chapter on convoys as attached.

 

There were the Admiralty Instructions - rather like Kings Regulations and the Army Handbook and Admiralty Instructions that related to specific operations like a particular convoy

Also may be worth looking at the Admiralty war diary

 

Another factor to be taken into account was the ports of origin and the destination. The WS convoys (troop convoys round the Cape to to Suez and the Indian Ocean would see ships loading in both Liverpool and the Clyde, sailing separately as two separate parts and then coming together when at sea). Not all the ships had the same destination, but there was a pattern that allowed all the ships destined for one port to be in the same column, allowing them to peel off the main convoy as their destination approached. See Munro's "The Winston Specials".

For convoy WS21S, the famous Operation Pedestal to Malta, there is reference to the convoy having to change its steaming disposition on several occasions. Cruising Disposition No 16 was adopted in the Atlantic. As they approached Gibraltar Cruising Disposition 17 was adoped to practice the convoy defence against dummy aircraft attacks, then Crising Disposition 15 to pass through the Straits of Gibraltar and ten back to Cruising Disposition 16. See Crabb's "Operation Pedestal"

Cruising Disposition 16 from 10-12 Aug (after Furious had detached) was 5 columns, the centre of which contained the battleships and carriers and the Charybdis bringing up the rear. Each of the 4 other columns was led by a cruiser with another cruiser bringing up the rear of the outside columns. The escort screen was largely disposed in an arc from one beam of the convoy to the other across its front.

Cruising disposition 17 used on 12 Aug, grouped the merchantmen in the centre and moved the warships out the corners, with the carriers and their AA cruiser escorts operating in a box to the rear of the convoy.This presumeably opened up the AA gunnery arcs to allow the escort to better defend the merchantmen and the carriers to turn into wind to launch and recover aircraft.

In the evening of 12 Aug Cruising Disposition 21 was adopted for the night passage throught he Sicilian Channel. This put the survivors iinto 2 columns so that they could follow the few destroyers with the TSDS minesweeps.

 

I also seem to recall that the East coast convoys travelled in only a very few columns, but were rather long, so that they could pass each other with the swept channels. That made them harder to defend against the E-boats.

 

I cannot find a "Book of Reference" entitled "Convoy" or similar ( apart from RN histories of six specific convoys ) but the list is the 1950 edition ( Kew reference ADM 234/1 ). I cannot find the earlier list anywhere: the instruction in the 1950 list was to destroy the previous list of BRs, so they did !

 

There would be an Operational Order for each convoy together with a Form A1 showing each ships position in the convoy. General instructions will not be in KR&AI but in BRs (Books of Reference) such as CB (Confidential Book) 03058 - Admiralty Instructions for Commodores of Convoys.
Whilst not entirely appropriate as it is post WW2 and US Navy much in this publication will be similar to RN especially Chapter 5 - Convoy Organisation Naval Control of Shipping

Tim

 

There are three documents that may help and should be at Kew - for each convoy. These are the Advanced Sailing Telegram, Cruising Order and the convoy Commodore’s notes.

 

National Archive Reference for CB 03058 (1941-45) is ADM 199/2372.

Tim

 

Hello Robert-w

I have obtained ADM 199/24 from Kew for Convoy H.N.25 which contains the Commodore Reports of Convoy H.N.25 by Captain J S Pinkney Master of SS Fylingdale, Rowland and Marwood’s Steamship Company Ltd. Whitby.

I have also details of the Advanced Sailing Telegram from several websites but not from Kew, but I have not located Cruising Order details.

Many thanks.

John H

 

In theory you can download RN historical documents from the Australian Navy website.

Publications | Royal Australian Navy

 

A typical convoy of that size (OG 79):
Columns to be 3 day 5 night cables apart.
Ships in columns to be 2 cables apart.
From memory a cable was 608 feet, the italic figures were typed in on the Cruising Order form.

 

A cable is 1/10 of a nautical mile or at least it was in WW2 over the years the definition of a cable has changed from period to period