"Convoy OB-70 wargame" Topic

OG-70 Wargame.
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My wargames group are play testing a WW2 Naval game involving convoys and anti submarine warfare. The rules will probably be available to the public in a few months. For our game last weekend, Big Trev took command of an Escort Group in charge of a British convoy, while our Baldric commanded the German forces. The convoy, OG-70 was from the UK to Gibraltar and set around late 1941.

BT was kind of lucky in drawing a reasonably strong escort for a fairly small convoy. The escort group he had could have found they were looking after as many as 40 merchant ships, but instead only had twelve, although they were fairly important vessels. The smaller number enabled him to deploy a tighter screen than usual and as he had drawn two old destroyers as part of it, he was able to place one astern as well as one up front. The stern escort would enable him to race to deal with threats, or to assist other escorts if needed. He placed his two flower class corvettes to port and starboard ahead of the convoy, his two ASW trawlers on each flank, and a pre-war sloop at the rear to keep that covered if the old destroyer had to rush off elsewhere.
The first morning move was uneventful, but the convoy had barely left sight of Northern Ireland when it encountered a single Fw200 Condor, which circled ominously for most of the afternoon move. As there was no air escort, or catapult ship with OG-70 they could only watch as it circled, sending out sighting reports.
The result of this came almost immediately after darkness, during the night move, when Wishart detected a U Boat, as it surfaced near the rear of the convoy, but ahead of the rear escorts. Wishart, which was already zigzagging at 15 knots, turned toward the contact and increased speed. The sloop Aberdeen failed to see the threat, but warned of its presence, turned in response, firing star shell to illuminate the area ahead of Wishart. The U Boat was caught by surprise and took evasive action, but too late. Wishart rammed U215 aft of the conning tower. Damage to the submarine was not immediately fatal, but Wishart was too close to engage with gunfire, and U215 attempted to slip away, despite a bulkhead hit and engineering damage. However Aberdeen, spotting the enemy illuminated by star shells, engaged with gunnery, causing further damage. As it turned out this was not really needed as U215 could not control her flooding, and also unable to dive, was abandoned by its crew. U215 subsequently sank. Wishart and Aberdeen picked up the survivors. The rest of the night went smoothly, without further contact. Wishart had lost her Asdic dome, but her damage from ramming the U Boat was relatively slight.
The morning move for day two resulted in Aberdeen picking up a HF/DF transmission from a U Boat that was obviously shadowing the convoy. However as she was the only ship so fitted, an exact fix could not be obtained. Big Trev decided to send the Aberdeen steaming directly down the line of contact and although the U Boat was not sighted, the transmissions ceased and it was presumed to have dived, thereby breaking contact.
The Afternoon move of day two brought a brief sighting of a ship out on the starboard bow of the convoy, at 15,000yds. Saladin now being the fastest ship was sent to investigate. Although unable to locate the mystery ship, she none the less found survivors in the water from a previous convoy and rescued them. This delayed her return to the convoy until the first hour of the evening move. Late in the afternoon a U Boat fired a torpedo from outside the escort screen and despite the long range it struck the SS Port Sydney, flagship of the convoy Commodore, which dropped out of her column and eventually sank. This was a score for U101. Aberdeen picked up survivors.
The night move of day two saw all hell break loose. Three separate submarines attacked the convoy, two of which penetrated the screen. U131 fired at the SS African Planter, but the torpedoes missed, one going on to strike the Ammunition ship MV Hammerfest, which blew up with a roar. The Escort Commander gave instructions for all units to perform ‘Operation Raspberry' while the merchant ships performed ‘Buttercup'. The U131 was caught on the surface and fired on by the corvette Marigold, and the destroyer Wishart, which had advanced up through the columns and also visually spotted the U Boat attempting to escape. With shells falling all around the U131 crash-dived. Having already lost her Asdic dome, Wishart was not much good in such a hunt, so as the convoy advanced past the scene, she was replaced by the sloop Aberdeen. Some thorough depth charging caught U131, which with batteries on fire leaking fumes, was forced to make an emergency surface. Unable to dive again, the guns of Aberdeen and Marigold banged away at her until eventually, with all motive power lost, due to some solid hits from Aberdeen, she was abandoned. Aberdeen returned to station, leaving Marigold to pick up German survivors.
In the meantime the Trawler Wardour was dealing with an intruder trying to enter the convoy from the port side. U99 was sighted moving in at high speed on the surface but was illuminated by Wardour, whereupon, the corvette Pink also sighted the danger and turned back to engage. U99 crash-dived after firing torpedoes into the port side of column 1. These missed their intended target, but went on to hit the Dutch tanker Brabant, in column 3. The tanker was severely damaged, caught fire and blew up. U99 was then hunted vigorously, and after some confusion, was considered to have been sunk by Wardour. Actually, she had made her escape, although severely damaged.
Directly ahead of the convoy, U102 ran in on the surface, slipping through the gap left by the corvette Pink, which was busy with U99. Her salvo of torpedoes scored a single hit on the African Planter, causing that vessel to slow down, but she was able to survive. U102 then dived, and was severely damaged by depth charges when Saladin arrived to sweep the area. The hunt continued for a time, but eventually an accurate depth charge pattern forced U102 to surface, where the crew quickly abandoned her.
To starboard of the convoy the ASW Trawler Yestor was intercepting a U Boat that appeared 1000yds off her port quarter when the merchant ships fired snowflake. U104 was fully illuminated when the trawler opened fire; along with the armed Merchant ship African Planter. The U Boat dived at once and escaped further detection, although Yestor searched thoroughly.
By the dawn of day 3, all escorts had resumed their stations, and the convoy speed had been adjusted to allow for the limping African Planter. During the morning a HF/DF contact was investigated by Aberdeen, which located the submarine, forced her down, and destroyed her with depth charges. The U Boat (U102) was acting as ‘squealer' to help other boats make contact. After being forced to dive contact was temporarily lost with the convoy.
In the afternoon of day 3 there were no further incidents and due to the original high speed of the damaged African Planter, something approaching the normal speed for a slow convoy could be reached. The break of contact obviously worked. The night passed peacefully, with no ships torpedoed and no submarine contacts.
At first light on the morning of day 4 at sea, a Fw200 Condor was sighted closing from astern, then a second was seen. The escorts and Merchants filled the sky with flak that damaged one Condor, forcing it to break off its attack. However the other machine flew over the SS Kinross, dropping a stick of bombs that left the merchantman sinking. The aircraft passed safely out over the front of the convoy and headed home as available escorts rushed to pick up survivors.
During the afternoon move another Condor picked them up and things started to bode ill for the night to follow, however only one U Boat (U244) made contact and she was driven off after a severe depth charging from two of the escorts.
Dawn of day five saw the convoy closing its destination and Big Trev was hoping that he would manage to get into Gibraltar without further trouble. However during both the morning and afternoon moves he was forced to send escorts out to drive off U Boats shadowing the convoy. Then late in the afternoon, he received news of yet another ‘squealer' out on his starboard flank. This time he decided it was too close to darkness and he wanted his fastest escorts with the convoy. It must be remembered that the Wishart was no longer of any use for hunting submerged submarines as she had lost her Asdic dome when ramming U215. She was stationed within the convoy where her gun armament might be of use if a U Boat got in among the columns and was illuminated. While Aberdeen was faster than the corvettes and trawlers, her margin of speed was not sufficient for her to be back in the screen by dark. Saladin was too important to be away for any length of time, being the flag of the escort commander.
Darkness fell on night five, and was soon split by gunfire as the trawler Yestor opened fire on a U Boat that attempted to penetrate the starboard screen. This boat was U301, which made a dash for the merchant ship columns in the hope of becoming harder to pursue. In doing so Baldric misjudged and cut things too fine. The bow of African Planter loomed up before him and U301 was cut in half by a merchant ship that had not even realised it was there.
Meanwhile U155 was racing in from 45deg astern of the starboard column, taking advantage of a gap left when the Yestor pursued U301. She had a perfect shot lined up in front of her and quickly torpedoed the old WW1 built ship War Sirdar, which miraculously survived, although severely damaged. She then put a torpedo into the Norwegian SS Vaargoss, but again did not achieve a sinking. U155 had just fired her stern tube at the African Planter when Wishart appeared moving at the fastest speed she could manage, considering the damage she suffered during the night melee of day two. U155 was quickly under her guns, and unable to be engaged, so Big Trev ordered her to ram, despite the risks. Wishart having no Asdic meant that if the submarine had time to dive, it would surely get away. To everyone's amazement Wishart survived her second ramming. U155 was unable to dive, but tried to make off on the surface, as her speed was still higher than the twice-damaged Wishart. At this point, the trawler Yestor, also misjudged things and rammed the stern of the much-damaged African Planter. Both ships survived, but the African Planter was now barely afloat and Yestor lost her Asdic dome. Ahead of the port column, U137 was attempting to get into the convoy columns when sighted by the destroyer Saladin and the Corvette Pink. The corvette was closest and opened fire with her 4" gun. However U137 was not about to be put off. Not having seen the Saladin closing her, she opened fire on the Pink with her deck gun, silencing fire from the corvette. Hits from Saladin took out the conning tower and U137 crash-dived. Both Pink and Saladin followed up with depth charge attacks that were rewarded with an underwater secondary explosion, after which contact was lost.
On the morning of day six the escorts reformed the convoy which was now restricted to only 3 knots due to the damage suffered by War Sirdar and Vaargoss, while the African Planter was now under tow. The Destroyer Wishart was badly damaged, the corvette Pink had no main gun, and the trawler Yestor had a crumpled bow from her collision with the rear of African Planter. Except for Wishart, which had no Asdic dome, none of the escorts had more than a single pattern of depth charges left. Fortunately luck was with the Convoy. The only contacts for the morning and afternoon moves of day six were Allied aircraft from Gibraltar. These took over the role of intercepting HF/DF contacts and forced the U Boats to break contact. The night was quiet and by dawn the convoy was well under the cover of Gibraltar. Due to its slow speed, it would take two more days to actually get into the harbour, but OG-70 was now heavily protected and no further enemy contacts occurred.

Post game we felt that too many U Boats were sunk. However in later reflection it occurred to me that one was sunk in collision with a merchant ship, in what was an accidental loss. At least three more could be considered lost due to inexperience, because our Baldric had been somewhat press ganged into being a U Boat commander and was not familiar with some of the advantages and disadvantages he was likely to be faced with.

In our next game we'll see if a bit of experience can turn the tide and sink more ships, than they lose.

Mal. Wright.

Thanks for the write up. I have always thought that the U-Boat war in the Atlantic was an area that offered great game ideas.

I look forward to reading more and hearing about your rules.

From what I have read, it did seem that a great many U-Boats were sunk. In later '42 / '43, not so much a problem, but if a '40 or '41 game, the losses seemed high.

Oh, ya. The photos are great!

It was too high. But I had to allow that poor Baldric was somewhat roped in as the U Boat commander and had never done anything like that before. Therefore I'm inclined to think some of the losses were purely due to inexperience.
We'll test that thesis next weekend.

Great report as always. And Im not even a naval wargames fan!

Didn't Baldric also take it in the shorts as the German DD Commander at Narvik?

Poor guy needs a win. How about letting him take Scharnhorst versus Courageous?

Nice battle report Mal.

The rules sound like fun. We've needed a good set of convoy rules for some time.

I look forward to their release.

What scale minis do you use for your games?

Best regards,

Rob

Nice report Mal & I 'd agree with your thoughts about the U-boat loss rate. The escort commander would be getting a 'gong' for that performance!

If you are interested I will be running another test game this Saturday evening Huw.

Balric did take a beating at Narvik, but at least in Convoy he potentially had enough forces to have wiped out the convoy and its escorts. With some more experience at the game, he just might too!

Mal.

Terrific report… I am very interested.
Could you please drope me a pm over there affshc.net/forums when your rules are out? Will they be printed, or a downloadable PDF?

Final details are not yet worked out, but I would expect the rules will be printed. We have still got some play testing to do yet, but at present they seem to work brilliantly. They will probably not need an extended development because I've being doing ASW and Convoy games for 30 years or so, and a lot of this is just finally putting into print, what my group have already been doing for a long time.

McKinstry said "Poor guy needs a win. How about letting him take Scharnhorst versus Courageous".

At fifty miles distance? Poor Baldric.

Or, give him the entire FAA and RN against a crippled Bismarck!

Crikey! Had ten U Boats and a couple of Fw200c Condors as it was. Lets not get too generous!!!

Mal, I'll see if I can organise some babysitting!

Great! I need some people who know the pointy end of a ship from the blunt end.

Pointy end goes into the iceberg doesn't it? If you can PM me the details at huw(dot)davies(at)rgh(dot)sa(dot)gov(dot)au please Mal & I'll be really nice to her indoors!