Convoy attack decisions | Forums

[LouLewis1967]

I ran into a situation over the weekend where I could not make up my mind about attacking a small convoy. This was 4 relatively small merchants (one 8K ton, the rest less than 5K), escorted by three ships in a triangle around them. The lead escort and starboard side were very small boats (Shimushu I think), and the port side one was not sighted.

The date is mid-March of 1943. The location is mid-ocean, on a line between Peleliu and the Celebes Sea. I think I am in range of at least 3 different Japanese airfields, although near the limit of all of their coverage ranges. No air patrols had been encountered since leaving Peleliu.

The weather was windy (13kts) with light fog (I had to be less than 6nm to see the ships) with no clouds. Sunset was only a few hours away. The moon was about 65% full and would be almost directly overhead at sunset.

Now, this is TMO2.5 without RSRDC, and I had plotted three course changes in the convoy already, radical turns of around 70 to 80 degrees, alternating between to port and starboard. Course changes were roughly 1:40 apart. Speed seemed to be 9 for the merchants, which were in a square box formation.

So, with the leading escort positioned to the left of formation (leading the port column), and the trailing escorts alternately peeling off to search 4000 to 5000 yards to their respective sides, I saw I could time a pretty good gap appearing on the starboard side once that aft escort split off. Waiting for a night surface attack would be pretty easy. On the other hand, with very choppy seas I felt I could get in pretty close for a periscope attack at dusk without being picked up on sonar.

I made my choice, which I can fill in later. But I was wondering what types of attacks some of the other captains might craft up from that situation.

[MWolfe1963]

Well, I think you listed two good options. I still play TMO2.2, but I believe he toned down the high visual factors some in 2.5, in 2.2 easy to get blasted at night 6000 yards plus.

WIth heavy seas you can about work at will, submerged I would've split the gap keeping a narrow helm to the near escort, when escort passed, pull off my attack.


EIther way, we expect a story of a successful attack, all ships sunk, but those lil merchants can be a pain to hit sometimes.

[LouLewis1967]

Yes, I think 2.5 has toned down the visual sensors. I remember reading that in the update, and have pretty much experienced it in the game. But I am always wary of just assuming they all have bad eyesight. Visual detection scales along with crew rankings, right? I am always expecting to run into a high-skilled crew and find out the hard way.

Anyway, no big suspense to build up about this. Here's what happened:

I got out in front of the starboard column after it got dark, on the surface. I was about 13000 yds in front and to the right, about 7000 yds off track. Watching the radar sweep, I saw the starboard escort peel back, waited until he was about halfway out, and started in at about 45degrees heading towards the front of the convoy. At about 5 kts I could slowly close and helm right and keep a sharp profile, hopefully closing to about 5000 yds and shooting at the two starboard ships (which happened to be the two biggest). It went perfect, up until I got set up for the final radar range / bearing input. The pips on the ppi were all jumbled. Because they had started another course change. Everything would now pass down my port side, but I was pretty far from their new track and trailing a little, with only visual AOB estimates in a very choppy sea at night. To make things worse, two escorts were now going to cross from starboard way too close to my bow. I swung hard to port, which brought my broadside facing the escorts. One started shooting, and I crash dove, made a quick periscope observation on the closest good target I could find (Akita Maru) which was also overlapping small freighter beyond. I fired a spread of three, using the TDC and a quickly computed 95% spread from about 6500 yds. Only got one hit, but it stopped the Akita dead in the water. Took a few depth charges, nothing close, and eventually came up and put one in the Akita and sank it.

So, lesson learned was I forgot to pay attention to the timing of the course changes, and got too focused on jumping the first opportunity that was presented when the escort peeled off. Other lesson was I probably would have been better off just sitting at radar depth from about 7000 yds off track and firing a large forward/aft salvo at all the targets. I could have been gone by the time they even knew what was happening.

[paulhager]

I agree with your decision to make a night surface attack. Best is to attack right after the last zig - that should give you the maximum amount of time. While it is nice when an escort peels off and gives one an opening, I still think it is better to attack when you know for sure that there will be no zig. Incidentally, I assume that you filed a contact report with HQ. If you track long enough, you might get 2 (or even 3) contact reports in, generating an attack objective for each.

You might find my account of a day long stalk followed by a night surface attack instructive. (See Large Convoy Sighted.) You'll notice that I fired full salvos from bow and stern tubes. That is one of my favorite attack modes and generally involves setting up at something like a 30º offset to the enemy track. I know what you're thinking: "He's going to be broadside to the lead escort." True but I was no closer than 4,000 yards since I had positioned the sub to attack the column away from the lead escort.

You'll note that I made my escape on the surface - enemy starshells were bursting at least 2,000 yards behind the sub. The key in the night attack is patience. After firing, move slowly. This is the high tension period of the attack because if you screw up, the convoy alerts, you start having shells splashing around you, and the your targets probably scatter. Oh, you also get depth charged.

[LouLewis1967]

I appreciate the replies. It's fun getting back into this game, and learning how to use the 3D TDC, coupled with 2.5's reduced visuals for the AI has made it a different challenge. I think that's what lead to my uncertainty about how to go after this convoy.

I used to have one attack: get in real close at periscope depth. Dealing with the subsequent depth charging was part of the deal, heck I would get pinged before I shot most of the time. I tried surface attacks but was not accurate with my data, and I felt like I was wasting torpedoes. The 3D TDC changed all that by providing much more accurate inputs, so I could get lots of hits from 5000yds or sometimes more.

But on the flip side, being submerged at 5000yds while using radar seems safer than maneuvering on the surface. You still leave enough time to get deep and clear before the escorts trace the torpedoes back, if they do at all.

[paulhager]

I appreciate the replies. It's fun getting back into this game, and learning how to use the 3D TDC, coupled with 2.5's reduced visuals for the AI has made it a different challenge. I think that's what lead to my uncertainty about how to go after this convoy.

I used to have one attack: get in real close at periscope depth. Dealing with the subsequent depth charging was part of the deal, heck I would get pinged before I shot most of the time. I tried surface attacks but was not accurate with my data, and I felt like I was wasting torpedoes. The 3D TDC changed all that by providing much more accurate inputs, so I could get lots of hits from 5000yds or sometimes more.

But on the flip side, being submerged at 5000yds while using radar seems safer than maneuvering on the surface. You still leave enough time to get deep and clear before the escorts trace the torpedoes back, if they do at all.

If memory serves, a majority of US Submarine attacks were made from the surface. Prior to TMO 2.5 (with the Tambor bug patch), I made plenty of night surface attacks but they had to be from long range. With TMO 2.5, night surface attacks can be conducted at something approaching historical distances. It is also now feasible to make night surface attacks with the Mark 18 - something that was nearly impossible with the earlier TMO version.

Also, I'd dispute that submerged is safer, particularly if the environmentals include <4 m/s wind. It is very hard to elude escorts after an attack late war. You have very limited speed for escaping. As I've noted many times elsewhere on this forum, I go to great lengths to avoid being depth charged. That's a very easy way to suffer career death.

Of course, if you encounter a fast moving TF, you may have no choice other than a daylight submerged attack. And, yes, you may have to take your lumps afterwards. In those instances I'm of the view that any US captain would probably take the risk, particularly if the target is a CV or a fat battle wagon. Under those circumstances, career death is acceptable.

[LouLewis1967]

Also, I'd dispute that submerged is safer, particularly if the environmentals include <4 m/s wind. It is very hard to elude escorts after an attack late war. You have very limited speed for escaping. As I've noted many times elsewhere on this forum, I go to great lengths to avoid being depth charged. That's a very easy way to suffer career death..

Sure, I was still speaking in the context of this situation, which had pretty high winds. If all the variables in the situation I posted were presented with a zero-wind condition, I would definitely be leaning away from any submerged attack.

[MWolfe1963]

The night surface attack has never been what it should be in the game. Often you can get in fairly close historically, but the second you expose your broadside, it's easy to be seen. I can under right conditions go in by the bow and pull of an attack at 2000 yards, but often get caught when I turn to escape, so you're forced to dive anyway at that range. I love the increased visuals and gun ranges of TMO2.2 for daytime, but they hurt you at night. The light values just don't work enough to adjust night visuals IMO.

[LouLewis1967]

The night surface attack has never been what it should be in the game. Often you can get in fairly close historically, but the second you expose your broadside, it's easy to be seen. I can under right conditions go in by the bow and pull of an attack at 2000 yards, but often get caught when I turn to escape, so you're forced to dive anyway at that range. I love the increased visuals and gun ranges of TMO2.2 for daytime, but they hurt you at night. The light values just don't work enough to adjust night visuals IMO.

Yeah, some of the historical accounts I have read are a lot closer than I have been able to get in 2.5. Problem is you never find out what "too close" is until the bullets start flying.

[paulhager]

The night surface attack has never been what it should be in the game. Often you can get in fairly close historically, but the second you expose your broadside, it's easy to be seen. I can under right conditions go in by the bow and pull of an attack at 2000 yards, but often get caught when I turn to escape, so you're forced to dive anyway at that range. I love the increased visuals and gun ranges of TMO2.2 for daytime, but they hurt you at night. The light values just don't work enough to adjust night visuals IMO.

In TMO 2.5, a fairly close attack is possible, as I described at the posted link. What I've found is it is still feasible to attack from between 3,500 - 4,000 yards from an escort, and that includes being broadside. The problem arises when your sub is close to an approaching escort's track - at least that's what I've observed. I don't know if the game models directionality of lookouts or not - my sense is that it does. Certainly at something like 3,500 yards with an escort bearing down on you, the sub better be pointed away at that point. In the night attack at the link, I discussed my targeting decision based upon the location of the near side escort. If you look at the last screenshot, the sub was a little over 4,000 yards away from the near escort running at flank and it was not spotted. I'm pretty sure that before I was able to pour on the coal, the escort was within 4,000 yards of the sub.

ADDENDUM: Since I was pointed only around 30 degrees away from the track, the only escort that saw the sub broadside was the leader, which may have been as close as 3,800 yards. The flank escort mostly got a view of the tail end of the sub as I turned away after the attack.