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View Full Version : Situation: Large convoy sighted at dawn - what do you do?



paulhager
02-20-2012, 06:17 PM
It's patrol #2 (LCDR Arthur Franz commanding, submarine is a Gar class), running standalone TMO 2.5. I've saved the game to take a break. Here's the sitrep:
Mixed sonar-visual attack in heavy storm two and a half days earlier netted an enemy Liner - 18,000+ tons. Ten torpedoes expended - 5 hits, 5 misses.
Torpedoes remaining: 10 Bow; 4 Stern.
HQ notified of enemy convoy just after dawn at 1110 (base time), 28 March 1942.
Only lead elements observed at 14,000 yards - much smoke signifying large convoy.
Speed 9 knots; course 242 true.
Environmentals - perfect visibiliy, clear skies, wind 4 m/s.
Discussion:
Currently, operating with two outstanding objectives - both are to sink enemy shipping. Environmentals favor enemy ASW combatants - likelihood of depth charge attack is high. Weather likely to remain clear throughout the day. Ephemeris shows sundown for this location is around 2330, moonrise around 2030 with the disk at 85% waxing gibbous.

Options:
Immediately close and engage convoy.
Maintain contact, attack at night.
There is no right or wrong answer here. I'm interested in other opinions.

fireftr18
02-20-2012, 08:02 PM
A lot depends on your heading and the targets bearing and heading. And if you have radar. That said, there is a basic setup. Stay as far from the convoy as you can and track it. Get ahead of it, and get roughly perpendicular to it and stop. Go to decks awash and wait until you see a ship or pick one up on sonar. When you do, go below the thermocline and track the convoy with sonar. Go silent and wait some more. Adjust as needed for range. When you're ready, come up to PD a have fun. Soon as you're happy, crash dive and get out of there. Be sure to remember to decrease engine speed again, you don't want the DD's to hear you.

MWolfe1963
02-20-2012, 10:18 PM
Well, I'm still playing 2.2 highly tweaked for myself, I made my sub more fragile and most escorts are pro's, so I would opt for a night surface attack from long range if weather remains calm.. I would shoot a few long range M14's with my stern facing the enemy, then haul arse, once the escorts see the torps they will come searching where I shot them from, but I will be long gone and do a closer attack on the unescorted flank. Course right now I'm playing a very serious career, my goal not to lose one crewman and no injuries other than mild.

paulhager
02-20-2012, 10:34 PM
A lot depends on your heading and the targets bearing and heading. And if you have radar. That said, there is a basic setup. Stay as far from the convoy as you can and track it. Get ahead of it, and get roughly perpendicular to it and stop. Go to decks awash and wait until you see a ship or pick one up on sonar. When you do, go below the thermocline and track the convoy with sonar. Go silent and wait some more. Adjust as needed for range. When you're ready, come up to PD a have fun. Soon as you're happy, crash dive and get out of there. Be sure to remember to decrease engine speed again, you don't want the DD's to hear you.

I took for granted that this thread would be read as a challenge/discussion. Apparently I wasn't clear. Sorry. To clarify - my previous post (Patrol 1 (http://forums.ubi.com/showthread.php/660031-Night-actions-18-January-1942)) dealt with successive attacks on the same convoy at night, hence the question/problem posed here. The two options from which to chose were stated as attack immediately (a daylight attack) or maintain contact and attack at night. My impression is that you are suggesting to immediately get into an attack position - that would mean a daylight attack.

On that assumption, recall from the sitrep that the weather is clear, low winds. These conditions favor the defense. The enemy will have a much easier time detecting the sub and destroying it. The immediate attack in good visibility has the advantage that the enemy is there now and you can quickly get into position, hopefully before a course change. Note: this is early 1942, so no radar.

Regarding the attack, I almost never approach from 90 degrees (see, for example, the two attacks in patrol 1). By coming in from 90 degrees under the above conditions, the enemy is presented with a favorable (for him) aspect ratio in nearly ideal ASW conditions. If you intend to turn away, you'll be doing so at slow speed. In 1942, all of the DD's will rapidly converge on your location and you'll be depth charged mercilessly. You'll have a hard time escaping because you can't go deep in a Gar nor can you go very fast.

ADDENDUM: I have some additional information. I was able to ascertain that the convoy is comprised of five merchants and three escorts.

This complicates the daylight attack. Safest would be a submerged attack from outside the screen. Militating against this is the likelihood that the Mark 14's will be detected and the ships will turn away, foiling the attack. The alternative would be to drop below the thermal, penetrate the screen and attack in close. You might escape by diving under the convoy. Given the environmentals you might also be detected and depth charged. (I go to great lengths to avoid being depth charged.)

paulhager
02-20-2012, 10:43 PM
Well, I'm still playing 2.2 highly tweaked for myself, I made my sub more fragile and most escorts are pro's, so I would opt for a night surface attack from long range if weather remains calm.. I would shoot a few long range M14's with my stern facing the enemy, then haul arse, once the escorts see the torps they will come searching where I shot them from, but I will be long gone and do a closer attack on the unescorted flank. Course right now I'm playing a very serious career, my goal not to lose one crewman and no injuries other than mild.

One complication is the lack of radar, which poses a bit of a challenge. TMO has frequent convoy/TF zigs and without radar maintaining contact is a bit of a challenge.

If the seas were heavier, I'd probably go for the immediate attack without giving it much thought.

As it is, I chose your option. Currently, the time is 1548. The convoy has changed course twice since being detected. I've been able to maintain a position between 14,000 and 15,000 yards bearing about 45 degrees from the lead escort. I only lost visual contact once but was able to reestablish using passive sonar.

donna577
02-20-2012, 11:15 PM
​I would opt for the night attack.....I have had Gar/Tambors to 450ft without a problem. By clicking on the depth gauge in the control room I have had them deeper, but not by much.

Mescator
02-20-2012, 11:39 PM
My initial instinct was to do a daylight submerged attack from range, but waiting on night would probably give you a better success rate.

MWolfe1963
02-21-2012, 12:36 AM
See, that's what I like about TMO alone, the constant course changes. Historically ships did this, but stayed to a base course you can somewhat figure and plot the base course and put yourself in a shooting position, with TMO it's a lil more random. Overall, groups do stay on a basic base course, but with TMO course changes can often be drastic, maybe you remember my Java Sea attack, dang group almost went in a large square covering 200nms, yet course changes about every 10 miles. There was no figuring where it may be porting. The other issue with TMO's traffic is much of it spawns and despawns in the open water, so groups may vanish in deep water right before your eyes. Overall, you should see course changes about every 10nms, if he set them any shorter it would put quite a load on your PC, but compare to RSRD, face it, it really doesn't have these zig legs, just look in the ME.

Obvious, we know somewhat how the AI will react, before I tweaked my settings I could easily go in most conditions and attack and escape. Why I increased thermals and silent running to be a lil more in my favor, my sub is fragile, one close charge hit is about sure death, two for sure.

Wait until you run into some of the TMO TF, much higher speeds than RSRD, with the constant course changes, enemy radar and meaner escorts.....be careful.

It's tough, I miss so much about RSRD where groups spawn and despawn at ports, take correct course, historical realism, etc., but like the functions of TMO. I'm working on a more traffic mod for TMO which will include more ships, rework the battles and add the larger convoys and invasion groups. TMO does traffic much different than RSRD, it uses many of the groups and spawn points over and over, but adjust groups spawn rate, uses generic settings for ships and loops. It's much faster to do traffic this way, but lacks much historic realism.

paulhager
02-23-2012, 02:56 AM
Following is a brief write-up of the attack. As previously stated, my plan was to shadow the convoy and attack at night. Calm seas and moonlight would work well for a night surface attack.

The first screen shot was taken at 1127 (GMT-10) 28 March, shortly after HQ responded to a contact report with the order to sink enemy shipping.

http://i1084.photobucket.com/albums/j408/paulhager/01_03-28-42_1127_AF02.jpg


The mission started with an order to proceed to a location, at which point I was given a sink ships order. Along with the recent order, I now had two orders that would be fulfilled if I sank sufficient tonnage.

Because the boat has no surface search radar, the only way of maintaining contact is via passive sonar and eyeballs. Fortunately, hydrophones are hull mounted (contrary to my earlier assumption), thus it’s possible to track the enemy while traveling at moderate speeds on the surface.

The next screen shot shows the navigation map after four hours have elapsed.

http://i1084.photobucket.com/albums/j408/paulhager/02_03-28-42_1532_AF02.jpg


A little later, the contact report icon solidified and I was able to send another contact report to HQ. I got another sink ships objective! That gave me three.

By 1930, the sinuous path of the convoy is easily seen in this screen shot of the nav map. It was still 4 hours to sunset.

http://i1084.photobucket.com/albums/j408/paulhager/03_03-28-42_1930_AF02.jpg


The next screen shot was taken at 2220 – the Sun was nearing the horizon. I had some important decisions to make. If the convoy were to continue on course, I’d either have to attack in the shallows or race around the island and attack from the other side. I didn’t want to do either. It might be possible to attack on the edge of the shallows during civil twilight but how would the AI react to that? Is it treated as full darkness or something in between daylight and darkness? While pondering this, I gave orders to race ahead to the ambush point. The contact icon once again solidified and I sent another report to HQ. I was ordered to attack escorts.

http://i1084.photobucket.com/albums/j408/paulhager/04_03-28-42_2220_AF02.jpg


Finally in position a quarter hour after sunset, a sound check revealed that the convoy was changing course to 211 true. It should continue on course for at least an hour, based upon past observations. I went to flank, careful to get no closer than 12,000 yards.

There were three ships in the near (starboard) column. From front to back, they were a Taihosan, an Akita, and a Kasagisan. The far column was headed by another Taihosan, followed by a Haruna (small) tanker. The three escorts were all Momi DD’s, one of which was operating in front of the far column. Having enemy escorts with a top speed two knots less than mine led me to feel quite sanguine about my prospects in the impending attack.

I was able to set up a little under 4,000 yards from the far column track – that put me 2,200-2,300 yards from the track of the near side escort. The Akita at 4,000 tons was the prime target. Next would be the lead Taihosan. Readers may wonder why I didn’t target the trailing Kasagian. The chief reason was the proximity of the escort. A secondary reason was that tankers are among the most valuable in terms of renown – even small ones are worth a torpedo. If I could time the shot optimally, there was enough target overlap that I might bag the tanker.

All torpedoes were set for 8’, impact pistol, and slow speed. The four stern tubes were fired in a wide spread at the Akita. Next, the near Taihosan got tubes 1-4. It was another wide spread, biased slightly astern. Finally, the Haruna got tubes 5 & 6. The sternward bias was fairly significant because it would definitely be alerted and turning by the time the torpedoes arrived. Torpedoes now away, I set course due West at two knots.

The first torpedo struck the Akita at 2355.

http://i1084.photobucket.com/albums/j408/paulhager/05_03-28-42_2355_AF02.jpg


Torpedo numbers 2 and 3 also hit – number 4 swept past the bow and continued on toward empty ocean. The Akita was dead and the checkmark appeared for three objectives!

The convoy began to react. Star shells blossomed 2,000 yards behind the sub, now traveling at 12 knots decks awash. I ordered surface. The Taihosan was executing a starboard turn when the first two torpedoes in the salvo struck far astern.

http://i1084.photobucket.com/albums/j408/paulhager/06_03-28-42_2356_AF02.jpg


It was enough – target two was dead. Two torpedoes continued on in the direction of the tanker, which was making a sharp turn to port. If I was going to get a good screen shot, I had to multitask: making certain the sub was moving away at 20 knots while watching on the external camera as the torpedo wakes converged on the tanker.

It’s interesting to watch an attack proceed to its denouement via the external camera. It’s a POV that no real captain ever had. At some point, that ballistic computer in your brain pan sends a message to its constituent parts to gin up the hormones for the proper emotional response. In my case it was pleasure. After torpedo three from the attack on the Taihosan harmlessly sailed by astern, torpedo four hit the tanker solidly in the rear quarter. As the Haruna slowed, the two torpedoes targeted on it struck amidships and in the bow. It too succumbed.

http://i1084.photobucket.com/albums/j408/paulhager/07_03-28-42_2358_AF02.jpg


Here is the final screen shot from the attack, taken two minutes later at 0000, 29 April. The near Momi is selected. If you look closely, you’ll see that its speed is “medium” and its course is WNW. It can’t see the sub.

http://i1084.photobucket.com/albums/j408/paulhager/08_03-29-42_0000_AF02.jpg


After a few more minutes elapsed, the Momi had turned to the South. It was not pursuing.

With 4 torpedoes remaining, I charted a course generally in the direction of home. A call to HQ produced no new orders.

Shortly before local noon, I picked up a fast moving convoy on passive. It wasn’t practical to try to keep pace with it so I closed to attack. I ended up sinking a Conte Verde Liner.

Final tally: 0 torpedoes remaining; 5 ships sunk – 18 hits, 6 misses, no duds; 40K+ tons; 4 objectives.

Magic452
02-23-2012, 06:32 AM
Great attack and some good shooting. WELL DONE!

Magic.

PS we defiantly need some better smilies.