Attacking large, well-escorted convoys

[MKalafatas]

TMO/RSRDC

In December, 1941 there are several large task forces approaching the western coast of Luzon. I've seen them at Lingayen Gulf and also Vigan.

I'm having a devil of a time trying to sink anything in the S-boat. No radar, of course. Must rely on sonar, which is fine if one dives sufficiently frequently to check it.

Trouble is, I can't fix the speed and course of the task force with any precision because of the activity of the escorts. They see me on the surface at night, long before the 3 minutes required to track a visible merchant.

If I submerge I'm safer, but can't see the merchants until they are very close. Sometimes they are so close that I'm unable to reach a firing position. At other times, the escorts are all over me and I don't notice a course or speed change.

I've fired about 11 torpedoes in these circumstances and haven't hit a thing!

Heckuva challenge. Any advice?

I should add: I'm a killer when it comes to unescorted merchants. Shooting accuracy is not generally a problem (I use manual targeting, O'Kane method).

[Rockin Robbins]

You'll have to play peek-a-boo. Sit at periscope depth. Use passive sonar to give you a bearing on which the raise the scope. At least that way you'll know he's in the field of view. Raise the observation scope to take your first observation. Lower the scope while you plot the result and start the clock. At 2:45 raise the scope to take your second observation at three minutes.

Even that can be messed up by a DD catching a whiff during the three minutes and making you too busy to get the second one done, and then you're back to observation #1 again. Rinse and repeat until you get the job done.

Convoys are a pain!:D But that's where the tonnage is, so we go there and hope for the best.

The real boats have accounts of exactly what you are going through. They couldn't see through the scope. They were seen on the surface. There were a lot of targets that didn't get engaged as a result.

[MKalafatas]

Thanks, RR. One modification I might make is just to shoot at the most convenient target, whatever it is, as opposed to the biggest target, which might be more difficult to reach or have closer escorts.

[Armistead]

I've attacked these groups many times. Early war escorts are push overs if you do the right things.

What I would do is sit in front and plot a course that puts you in the middle of the convoy, stay as narrow as you can and work between the front and flank escorts...main thing is not to expose your broadside. Go deep, below the thermal using silent running, when the front escort passes you, come up and attack. You won't have time for 3 minute rules, etc, may see your scope, just use the stad, in close you can get accurate readings and speed.

If I'm between the escorts, I always helm to keep my bow nose pointed at the lead escort until he passes.

Bad thing with OKane, takes a lil time and usually leaves your broadside open to a escort. The good thing with these big groups is you can come in from the front as stated and pop enough and still have plenty of targets to shoot at.

[Bubblehead1980]

TMO/RSRDC

In December, 1941 there are several large task forces approaching the western coast of Luzon. I've seen them at Lingayen Gulf and also Vigan.

I'm having a devil of a time trying to sink anything in the S-boat. No radar, of course. Must rely on sonar, which is fine if one dives sufficiently frequently to check it.

Trouble is, I can't fix the speed and course of the task force with any precision because of the activity of the escorts. They see me on the surface at night, long before the 3 minutes required to track a visible merchant.

If I submerge I'm safer, but can't see the merchants until they are very close. Sometimes they are so close that I'm unable to reach a firing position. At other times, the escorts are all over me and I don't notice a course or speed change.

I've fired about 11 torpedoes in these circumstances and haven't hit a thing!

Heckuva challenge. Any advice?

I should add: I'm a killer when it comes to unescorted merchants. Shooting accuracy is not generally a problem (I use manual targeting, O'Kane method).

RSRD's enemy visuals for escorts is far too high, there is a patch them brings them down to more realistic levels with TMO.

http://www.subsim.com/radioroom/showpost.php?p=1520697&postcount=4


Download and just enabled after RSRD.Also a nice radar fix as their radar is like Allied radar by default(stock game thing) and the sonar fix for Type A/B/ C/D escorts gives them their active sonar as for some reason they did not have it, even in mid 1944.With their super visuals nerfed, you should be able to get into a position that makes a submerged approach possible.

[Rockin Robbins]

Thanks, RR. One modification I might make is just to shoot at the most convenient target, whatever it is, as opposed to the biggest target, which might be more difficult to reach or have closer escorts.

A great point. Nothing makes things go in your favor like a little gratuitous chaos! They are in perfect formation with all lanes covered until you disturb the system. Then chaos breaks loose, opening avenues of approach that wouldn't have been available.

And yes, when chaos breaks loose, Dick O'Kane attacks are much less useful than other tactics. Dick O'Kane is primarily an ambush technique.

[MKalafatas]

Thanks, everyone --- excellent ideas in there. Starting a new career to try 'em out.

[Ruff EL]

ive assaulted these convoys with TMO and RSRD installed and came away quite successful. My technique was pretty simple, once i determined speed, which wasnt too difficult at decks awash at night in rough seas (guess i was just lucky there or had good lookouts). After that was determined i dove to 330 ft and went streight in past the ring of 16-20 various escorts circled around the juicy center of the convoy...they didnt sense a thing. Like mentioned above, you gotta keep your hull narrow in relation to the escorts, and the effective depth of their sonar is usually only around 310 ft or so in early war situations so stay deeper than that, this might not work for you in the S boat as i dont know their max depth capability (never used one).

hope this helps some

[MKalafatas]

The deepest I've been in an S-boat is 240'. Afraid to push it more than that. I like your "decks awash" idea. That never occurred to me!

[Dignan]

RSRD's enemy visuals for escorts is far too high, there is a patch them brings them down to more realistic levels with TMO.

http://www.subsim.com/radioroom/showpost.php?p=1520697&postcount=4


Download and just enabled after RSRD.Also a nice radar fix as their radar is like Allied radar by default(stock game thing) and the sonar fix for Type A/B/ C/D escorts gives them their active sonar as for some reason they did not have it, even in mid 1944.With their super visuals nerfed, you should be able to get into a position that makes a submerged approach possible.

Are these still compatible after the TMO 2.5 update?

[Dignan]

You'll have to play peek-a-boo. Sit at periscope depth. Use passive sonar to give you a bearing on which the raise the scope. At least that way you'll know he's in the field of view. Raise the observation scope to take your first observation. Lower the scope while you plot the result and start the clock. At 2:45 raise the scope to take your second observation at three minutes.

RR,

In regards to the method you describe above, when you say "take an observation," what are you basing the range observation on? Stadi? Range slide ruler and hash marks? Using the map contacts to plot marks? Best estimate?

Just trying to get an idea of how other people do this. I have been on a "no map contact update" kick lately, which makes short peaks to get a plot with a semi-decent range very challenging. Especially with escorts nearby.

[torpedobait]

The deepest I've been in an S-boat is 240'. Afraid to push it more than that. I like your "decks awash" idea. That never occurred to me!

My last S Boat imploded at about 432 feet - Didn't go that deep by choice, of course. I had sustained heavy damage by gunfire from an unseen DD. We never had a chance...

[Rockin Robbins]

RR,

In regards to the method you describe above, when you say "take an observation," what are you basing the range observation on? Stadi? Range slide ruler and hash marks? Using the map contacts to plot marks? Best estimate?

Just trying to get an idea of how other people do this. I have been on a "no map contact update" kick lately, which makes short peaks to get a plot with a semi-decent range very challenging. Especially with escorts nearby.

Yeah, I'm afraid I'm talking about the dag blasted stadimeter, then plotting the positions on your nav map so you can read the range off using the compass. You can use active sonar or come up to radar depth (but not with an S Boat!) to get better numbers if you wish.

Yup I hate the stadimeter, but sometimes it's the best you got and then you use it.:D

[Rockin Robbins]

My last S Boat imploded at about 432 feet - Didn't go that deep by choice, of course. I had sustained heavy damage by gunfire from an unseen DD. We never had a chance...
That's life in the ole S-Boat for you. You're down and out, never had a chance but at least you'll go down fighting anyway. At least the enemy will know you were there.

Ever see the poster of the frog shooting a bird at the eagle swooping down with his claws out? That's us in an S-Boat.

[Dignan]

Yeah, I'm afraid I'm talking about the dag blasted stadimeter, then plotting the positions on your nav map so you can read the range off using the compass. You can use active sonar or come up to radar depth (but not with an S Boat!) to get better numbers if you wish.

Yup I hate the stadimeter, but sometimes it's the best you got and then you use it.:D

I've been reading "Wahoo" by Dick O'Kane. When he describes their targeting and plotting sequence they don't mention the stadimeter. How did real sub crews get a range on a target? In the book, they just raise the scope, the scope operator calls out the bearing, the range (is he estimating) and AOB (which I know they were just estimating by eye) and then they lower the scope and the plotting team would make the plot. Was he just leaving out the gritty details of data collection with the stadimeter or did they not use it?

[Platapus]

Of course if attacking well escorted convoys was easy, they would not have bothered to escort them. :D

[TorpX]

I've been reading "Wahoo" by Dick O'Kane. When he describes their targeting and plotting sequence they don't mention the stadimeter. How did real sub crews get a range on a target? In the book, they just raise the scope, the scope operator calls out the bearing, the range (is he estimating) and AOB (which I know they were just estimating by eye) and then they lower the scope and the plotting team would make the plot. Was he just leaving out the gritty details of data collection with the stadimeter or did they not use it?

IIRC, O'Kane and crew used the stadimeter when at the periscope. (Some boats had the new periscope radar.) At the surface they could use either the radar, periscope stadimeter, or binocular reticle (which was marked in milliradians). Radar, while an important tool, was not perfect; it could malfuction, be fooled by weather, or alert the enemy. The stadimeter, and optical reticles required identification of the ship in question, or at least an estimate of its mast height.

I believe the stadimeter scale was actually on the opposite side of the periscope, and thus the captain would call out "range mark", so one of the crew could read off the indicated range and plot the position. In other words, he would not know what range the stadimeter gave, until after the scope was lowered. (This had the benefit of allowing the observer to concentrate on making a quick, concise observation and not being biased or confused by what he expected the range should be.) The Captain really had no way of instantly knowing the range in real time beyond what he could see intuitively. This is one reason why torpedo attacks were not usually done "on the fly". Instead, the Captain would study the plot, and decide to launch on the next observation, by announcing "final bearing and shoot".

It's too bad, Ubisoft didn't pay more attention to these aspects of the sim.

[Armistead]

I've been reading "Wahoo" by Dick O'Kane. When he describes their targeting and plotting sequence they don't mention the stadimeter. How did real sub crews get a range on a target? In the book, they just raise the scope, the scope operator calls out the bearing, the range (is he estimating) and AOB (which I know they were just estimating by eye) and then they lower the scope and the plotting team would make the plot. Was he just leaving out the gritty details of data collection with the stadimeter or did they not use it?

I've read the book a few times, I think it reads several times Dick saying "bearing, range, etc...submerged they were getting range from the stad.
Also possible radar...Okane preferred it, but would tune range with the stad I would think. Okane also used other methods, basically what we refer
to as the 90 attack, range doesn't matter.

[Dignan]

Thanks for the comments guys. I think you're right. It was probably a combination of tactics and tools.

In the game my only problem is that my periscope seems to lack "spotting ability" until targets are within about 5,000 yards, even on clear daytime conditions. This makes getting a good plot ahead of firing time difficult. For example I can be on the surface and my lookouts will call out visual contact bearing and range estimates (ctrl-V) from very long ranges. As soon as I submerge and raise the scope, I can't get a lock which means I can't get a stadi reading. Why is there such a difference in visual spotting ability between periscope and surface spotting? Shouldn't it be the same?

Is this the result of a mod? I'm running TMO 2.5, RSRDC and the new OTC mod.

[Armistead]

Not sure what you mean by "spotting ability" Even if I can't lock on, I can see ships to probably 5-7 nms on a clear day, if playing no cams and contacts, least get some idea and with 3 radar mod in TMO fairly easy to plot a course

I haven't tried OTC yet, next on my list, maybe it's corrected some issues.
For one I hate any dial/tool that doesn't move on it's on. I would rather have have a scope/stad that didn't have any lock on features.. However, I can lock on targets for a few seconds at around 9000 yardsand hurry and do a stad measurment. Sometimes it unlocks after you pull the stad down, but just lock it back and make sure ship is ID'ed when you click a stad measurement, but honestly it's about impossible to get accurate stads over 3000 yards in game

Be interesting to do a lil research and see how well range was calculated at long ranges with the stad, seems I read they were getting fairly accurate ranges at much longer ranges than we do. One issue is the mast in game tend to fade out and hard to see the tops.

[Dignan]

Not sure what you mean by "spotting ability" Even if I can't lock on, I can see ships to probably 5-7 nms on a clear day, if playing no cams and contacts, least get some idea and with 3 radar mod in TMO fairly easy to plot a course

I haven't tried OTC yet, next on my list, maybe it's corrected some issues.
For one I hate any dial/tool that doesn't move on it's on. I would rather have have a scope/stad that didn't have any lock on features.. However, I can lock on targets for a few seconds at around 9000 yardsand hurry and do a stad measurment. Sometimes it unlocks after you pull the stad down, but just lock it back and make sure ship is ID'ed when you click a stad measurement, but honestly it's about impossible to get accurate stads over 3000 yards in game

Be interesting to do a lil research and see how well range was calculated at long ranges with the stad, seems I read they were getting fairly accurate ranges at much longer ranges than we do. One issue is the mast in game tend to fade out and hard to see the tops.

What I'm referring to is the ability of your watch officer to call out range estimations by pressing ctrl-V. Once I go to periscope depth and look through the scope at the target, my watch officer says "No visual contact" when I ask for range. A 2 year old looking through the scope could clearly see that there is a ship. Not until it gets to about 4 to 5k yards does it get recognized. So why is there such a difference between the surface and periscope view in your crew's ability to visually spot a ship?

I agree that the stadimeter is pretty useless beyond 5,000 yards.

[Sailor Steve]

Your Watch Officer isn't looking through the periscope; you are. His ability to estimate range is based on the fact that he's standing beside you on the bridge, so it doesn't work when submerged. In SH3 your Weapons Officer could read the range and bearing off the dial on the periscope and give a far-too-accurate 'estimation' of range and bearing. In SH4 that function was disabled. You're on your own.

[Rockin Robbins]

US Navy Submarine Periscope Manual 1946 (http://www.maritime.org/fleetsub/pscope/chap4c.htm#4J), page 99:

The device gives readings independent of the focus setting of the individual observer. It is capable of bringing into coincidence two points of the image that subtend an angle of from 0 degrees to not more than 2 degrees of the field at high power. It is provided with duplicate scale dials of Bakelite attached to the outside of the periscope so that range and course angle data may be read by an assistant, if desired. One set of scale dials is located under the eyepiece at the lower end of the eyepiece box, and the other set diametrically opposite on the back of the periscope. Such scale dials are not less than 2-inch outer diameter in the case of the smallest scale dial, and so located as to be easily readable. The graduations and numbering on each scale dial are clear and legible and each scale dial occupies as great an angular portion on the dial on which it is engraved as is practicable. The angular movement of the scale dial or scale dials connected to the handwheel is directly proportional to the angular movement of the handwheel.Anyone see something completely unexpected in this quote?:ping:

[Armistead]

Your Watch Officer isn't looking through the periscope; you are. His ability to estimate range is based on the fact that he's standing beside you on the bridge, so it doesn't work when submerged. In SH3 your Weapons Officer could read the range and bearing off the dial on the periscope and give a far-too-accurate 'estimation' of range and bearing. In SH4 that function was disabled. You're on your own.


So who is looking in the scope when I'm at the map screen and I get the message "ship spotted"...that's the AI, not me:O:

The issue is the AI can't connect with us on what we see, we see it, the subs AI may not. Course you can improve the crews visual ranges, etc. Often in TMO 2.2 I can get shot at at over 5nms, crew can't see crap to warn me.

But as you said, in many ways we're on our own...

[Dignan]

Your Watch Officer isn't looking through the periscope; you are. His ability to estimate range is based on the fact that he's standing beside you on the bridge, so it doesn't work when submerged. In SH3 your Weapons Officer could read the range and bearing off the dial on the periscope and give a far-too-accurate 'estimation' of range and bearing. In SH4 that function was disabled. You're on your own.

That's realism I guess. :DL I knew it wasn't actually the WO looking through the scope but I was more referring to the ctrl-V function. I suppose that makes sense that it wouldn't work when at PD.

So this isn't so much of a problem in a boat that has radar but when you're in an S-boat what are some methods for plotting an approaching target from Peri depth when the target is still too far away for the game's periscope to "lock on?"

[Sailor Steve]

That's realism I guess. :DL I knew it wasn't actually the WO looking through the scope but I was more referring to the ctrl-V function. I suppose that makes sense that it wouldn't work when at PD.
Since I've never used that function once in five years, I guess I can't help.

[Rockin Robbins]

Hmmmmmm.... Nobody surprised by the quote from the Periscope Manual. I guess it's all old news there then.:hmmm:

[Diopos]

Hmmmmmm.... Nobody surprised by the quote from the Periscope Manual. I guess it's all old news there then.:hmmm:

:yep:

That manual I read. Of course I cross checked it with Ubi's manual. (Uhmmm sorry just had a side effect from my medication !!!!!:doh:)

.

[TorpX]

US Navy Submarine Periscope Manual 1946 (http://www.maritime.org/fleetsub/pscope/chap4c.htm#4J), page 99:

It is provided with duplicate scale dials of Bakelite attached to the outside of the periscope so that range and course angle data may be read by an assistant, if desired. One set of scale dials is located under the eyepiece at the lower end of the eyepiece box, and the other set diametrically opposite on the back of the periscope.



Anyone see something completely unexpected in this quote?:ping:

That is what I was trying to say in post 17. I was going by pictures of the periscope I've seen. I think this can be seen in some old movies, too.

What is completely unexpected?





That's realism I guess. :DL I knew it wasn't actually the WO looking through the scope but I was more referring to the ctrl-V function. I suppose that makes sense that it wouldn't work when at PD.

So this isn't so much of a problem in a boat that has radar but when you're in an S-boat what are some methods for plotting an approaching target from Peri depth when the target is still too far away for the game's periscope to "lock on?"

With my mods, ctrl-v just gives bearing.

I agree that the lock failures, and the inability to see the mast tops clearly are problems. When I do plots, the long distance observations are more for the purpose of getting me close, than for a firing solution. At least a few close range observations are needed for a solid firing solution, (unless you have RADAR).




One of the things I really loved about SHCE, was that there was a well modeled horizon. When you submerged it actually reduced the range of your vision. If you went up to radar depth for a high-periscope search it improved, and if you were surfaced it was even better.

[mobucks]

Just fan shot the damn convoy and hope for a hit. Luzon is hours away, go reload. :|\\
I hear ya about those early convoys west of Luzon in RSRDC. One time, I swear, I was in convoy alley. Every hour as I traveled north, a new convoy put me down. It was just too much for my S-boat. I got frustrated and shot from the hip with a fan shot. No hits, and then I died.

The best awnser I've seen is to submerge deep with a small aspect to lead escort and surface in the middle of the convoy. The targets will be so close, you can just shoot from the hip at that range with your "seamans eye" and have pretty good results. Takes a bit of practice, but, practice makes perfect. Good luck.

[timmyg00]

US Navy Submarine Periscope Manual 1946 (http://www.maritime.org/fleetsub/pscope/chap4c.htm#4J), page 99:

Anyone see something completely unexpected in this quote?:ping:

The "course angle data"?

-TG

[MKalafatas]

To me, the most daunting aspect of approaching these convoys is their sheer size. Without radar, one is restricted to visual and sonar cues. Visual cues are difficult because the escorts are so alert and --- as was mentioned --- superior. Frequently they see us before we see them.

So we're left with sonar. But if you're flanking the convoy from beyond visual range to get ahead of them, sonar will not capture the entire convoy. You'll get a section of arc, wherein resides at least a portion. But you don't know the layout, the position or course of the lead escort, the location of merchants, etc...

It takes many hours to figure this out, particularly in the sluggish S-boat.

Just finished an encounter with a convoy of 6 merchants, 1 light cruiser, and 18 (!) destroyers and subchasers. I caught them north of Vigan but they ran over me and I couldn't get off a shot. Tracked them for 30+ hours, making seven separate approaches, until finally I reached a firing position 125 nm NW of Vigan on their return leg. Was lucky to sink a merchant (that I didn't even see) when torps missed the light cruiser.

[TorpX]

The "course angle data"?

-TG

Good catch. I guess the target's course is mechanically computed from the observed AOB? I wish they had a detailed diagram of this.


To me, the most daunting aspect of approaching these convoys is their sheer size.
This reminds me of a small item. If I spot a large convoy, and it is daytime so I must make a submerged approach, I will start my approach on a target near the front, if possible. (It may not be possible; it depends on how far off the track you are.) The reason for this is since I cannot ID the targets at a long distance closing on one near the front allows me to alter my approach and attack one farther back if I choose, but if I close on one toward the rear, I will likely be stuck with that choice, as all other targets will be passing, before I am ready for the attack. Getting farther ahead allows for greater flexability in your attack.