Determined intercept

[Albrecht Von Hesse]

On my 15th patrol, August 1943, I was headed down to quandrant EH. Weather was brisk but clear, rather pleasant in fact.

I'd no encounters the entire time. Not an aircraft nor ship the entire way. Around quandrant DT I received a radio report of a large enemy convoy, one moving at a respectable 13 knots. Plotting their course, I began an intercept approach. Considering they were approximately 400 klicks out I didn't expect an accurate interception, if any at all.

Three quarters of the way there BdU gave an updated contact report. Replotting it showed my long-range estimation was (surprisingly!) within 10 klicks of their current position. Making a minor adjustment I continued along at flank speed, then came to a stop at my plotted intercept point. And waited.

And waited.

And waited.

Based on course, speed and elapsed time I knew there was a weasel in the henhouse somewhere. I submerged, and did a 360 hydrophone check. Somehow, after almost a full day of steaming in a straight undeviating line, the convoy decided, about 50 klicks from the intercept point, to make a course change. They were now just passing behind me, and they had to be more than 16 klicks out because I couldn't see them, only hear them.

Back on the surface I plotted a new course, then went to flank speed. Within fifteen minutes I had smoke on the horizon. Within another ten I could spot them visually via UZO and binoculars.

Normally I do not make daylight surface attack intercepts, especially from 16 klicks out on a virtually dead calm day. But due to their course, I was going to lose them if I didn't go right after. I couldn't do the "90 degree dog-leg out of visual/flank speed to pass/90 degree dog leg back to intercept" approach I usually do for intercepts due to their speed and course. I figured 'what the hay' and bored after them. The worst that would happen is I'd have to abort the pursuit.

I got to within 10 klicks without any sign that I'd been spotted, and actually was cutting the vector and closing. I knew it would be only a matter of time before they spotted me, so I decided to pad the odds by going deck awash. Besides, if I have to crash-dive my IXC, it only takes 15 seconds to fully submerge if I'm at deck awash.

But I couldn't get my %$^# bow to go fully under, and it was blasting up a spray I was sure could be seen for klicks. Especially with me running at flank speed. I set the depth for 7 meters. Then kept nudging the needle more and more, until almost at 8 meters. And still the bow wouldn't go fully under.

The following is what the pursuit approach looked like at around 5-6 klicks out:

http://i96.photobucket.com/albums/l192/Albrecht_von_Hesse/1.jpg
http://i96.photobucket.com/albums/l192/Albrecht_von_Hesse/2.jpg
http://i96.photobucket.com/albums/l192/Albrecht_von_Hesse/3.jpg

You might notice the lack of spray. You'll never guess how I managed it either.

I fully manned the bow torpedo and bow quarters!

I was shocked that it worked. But it did! Nothing else worked, but within a minute of fully crewing those two compartments, my bow stopped blasting up spray.

I still couldn't approach as close as I usually do, so before I slowed up I took aim at two large tankers, and fired one steam torpedo at each from 6.5 klicks out, with their speed set at medium and impact-pistolled for 4 meters.

Submerging I counted off the almost six minute run . . . and got another shock when I heard a detonation.

This is what I saw after 30 minutes of running submerged along behind the convoy:

http://i96.photobucket.com/albums/l192/Albrecht_von_Hesse/4.jpg

Not the best intercept I've ever made, I'll admit. But I winged one. And after another hour I did a slow submerged approach and finished it off with a second torp.

Still, it was an interesting approach, if for no other reason than struggling to find a way to keep from blasting a spray up that might as well announce my boat's after you.

[Dodger01]

I am always impressed by how you make your approaches. The careful and planned methods, as well as the fact that you make a concerted effort to identify the flags before firing. I am learning from your efforts, and I thank you for that :-)

[Der Teddy Bar]

Ya gotta hava bigga ones to pull off a daring attack like that :rotfl:


BTW, great shooting :up:

[AVGWarhawk]

Interesting about shoving your men to forward torpedo room and it worked. I will give that a try. I have seen convoys make sweeping course corrections so shadowing can be tough. Normally I look to see how often the change course back and fourth. You will see a pattern. Shadow with the predicted path you see by observing. Once in front of the projected path submerge and wait for the goose to come to your table:up:

[TarJak]

Kudos Albrecht! I've been wondering how to keep the nose down and stop the spray.:yep:

Nice work and your determination impressed me. Why didn't you try for an angled end around. I've found running flank at about 30 to 45 degrees to the target's course runs me out far enough to escape the notice of the escorts. You then have to do the long run to get ahead. Guess it all depended on their speed. Were they a fast convoy doing +9kts or a slow one?

[mookiemookie]

Outstanding.

Great strategy and absolutely something I'll have to add to my repertoire. Way to press the attack! :up:

[Albrecht Von Hesse]

Wow! Thanks everyone for the compliments! :|\\



Nice work and your determination impressed me. Why didn't you try for an angled end around. I've found running flank at about 30 to 45 degrees to the target's course runs me out far enough to escape the notice of the escorts. You then have to do the long run to get ahead. Guess it all depended on their speed. Were they a fast convoy doing +9kts or a slow one?

Actually they were doing 13 knots. The fastest I've ever seen for a non-task force convoy.

Normally what I do when I encounter a convoy is immediately go to dead stop (unless it's bad weather and they're within 2 klicks :p ). Once I'm at 0 knots I pick a ship, lock my UZO on it and take bearing and range readings, marking that on the map relative to my position. I do that twice more, at 5 minutes and 10 minutes, then connect the points to set a course for them.

I place the compass at the first point and draw a circle. Depending on the weather and the mod I'm running (and at times other factors, like the year and number of escorts) the circle is anywhere from 8 klicks to 20. My course line is at least 200 klicks long, and I'll draw another circle (same-sized) at the middle and at the end. Next thing I do is plot a course, at flank, away from the convoy and out to the border of the first circle. The circles are drawn at what I estimate is the visibility range of the convoy (if they have radar I'll make the avoidance circle lots bigger that I do for visual avoidance).

Once I'n chugging away, and hopefully still undetected, I plot a course parallel to the convoy, by connecting my course tangent to the middle and end circles. Now things get a bit 'math-y'. What I want to do is travel the minimum distance necessary to intercept. This is for two reasons: one is that the longer I travel, the more any errors in plotting accumulate and grow, and the other is the longer it takes to intercept, the more likely the convoy will make a course change and/or I'll be spotted by aircraft or another ship.

Based on the convoy speed and my flank speed I set my distance so that when I reach a set point (where I'll plot a forth circle and set my course tangent to it) and turn 90 degrees to the convoy course, that when I reach 1 - 2 klicks away from the plotted convoy course I'll be around 20 klicks ahead of them. I choose 20 klicks for two reasons: that's far enough away to remain beyond their visual and radar range, yet is close enough that when I submerge I can pick them up on passive hydrophones.

Then it's usually just a matter of waiting. Sometimes I'll re-surface and do a surface attack approach (early years :D and at night) but normally I'll make creep adjustments submerged and sneak past the forward escorts until past and inside their screen.

@TarJak

I couldn't do that with this convoy TarJak because at the point you see they were between 6 - 9 klicks out, and on a divergent course between 120 - 130 port AoB. At their speed, and course, and also because they'd already made one unexpected radical course change, I decided trying to outflank and re-approach them would likely fail. That happens of course :hulk: but that's life.:p

[P_Funk]

I was shadowing a convoy recently and I was on perfect prallel course to wait for dusk. Well suddenly the lead escort turns straight at me and I wonder if he saw me or not. Well soon enough I see the rest of the convoy turn at me too but that course change was rather severe. A real surprise. But the good news is that the major course change turned it into an Atlantic convoy when it was looking like a Gibralter convoy.:rock:

Convoy course changes are such a pain, especially since it takes so much time to plot the new course and line up abreast. That's usually an hour or two of real life gone! And not even an attack.

[AVGWarhawk]

Wow! Thanks everyone for the compliments! :|\\



Nice work and your determination impressed me. Why didn't you try for an angled end around. I've found running flank at about 30 to 45 degrees to the target's course runs me out far enough to escape the notice of the escorts. You then have to do the long run to get ahead. Guess it all depended on their speed. Were they a fast convoy doing +9kts or a slow one?
Actually they were doing 13 knots. The fastest I've ever seen for a non-task force convoy.

Normally what I do when I encounter a convoy is immediately go to dead stop (unless it's bad weather and they're within 2 klicks :p ). Once I'm at 0 knots I pick a ship, lock my UZO on it and take bearing and range readings, marking that on the map relative to my position. I do that twice more, at 5 minutes and 10 minutes, then connect the points to set a course for them.

I place the compass at the first point and draw a circle. Depending on the weather and the mod I'm running (and at times other factors, like the year and number of escorts) the circle is anywhere from 8 klicks to 20. My course line is at least 200 klicks long, and I'll draw another circle (same-sized) at the middle and at the end. Next thing I do is plot a course, at flank, away from the convoy and out to the border of the first circle. The circles are drawn at what I estimate is the visibility range of the convoy (if they have radar I'll make the avoidance circle lots bigger that I do for visual avoidance).

Once I'n chugging away, and hopefully still undetected, I plot a course parallel to the convoy, by connecting my course tangent to the middle and end circles. Now things get a bit 'math-y'. What I want to do is travel the minimum distance necessary to intercept. This is for two reasons: one is that the longer I travel, the more any errors in plotting accumulate and grow, and the other is the longer it takes to intercept, the more likely the convoy will make a course change and/or I'll be spotted by aircraft or another ship.

Based on the convoy speed and my flank speed I set my distance so that when I reach a set point (where I'll plot a forth circle and set my course tangent to it) and turn 90 degrees to the convoy course, that when I reach 1 - 2 klicks away from the plotted convoy course I'll be around 20 klicks ahead of them. I choose 20 klicks for two reasons: that's far enough away to remain beyond their visual and radar range, yet is close enough that when I submerge I can pick them up on passive hydrophones.

Then it's usually just a matter of waiting. Sometimes I'll re-surface and do a surface attack approach (early years :D and at night) but normally I'll make creep adjustments submerged and sneak past the forward escorts until past and inside their screen.

@TarJak

I couldn't do that with this convoy TarJak because at the point you see they were between 6 - 9 klicks out, and on a divergent course between 120 - 130 port AoB. At their speed, and course, and also because they'd already made one unexpected radical course change, I decided trying to outflank and re-approach them would likely fail. That happens of course :hulk: but that's life.:p





There are two types of convoy just as in the war. Fast and slow. So it is nice to know that this was modelled into the game:rock:

[Sailor Steve]

NYGM has a lot more types than that. Their convoys change speed every time they change direction!:rock:

[TarJak]

I couldn't do that with this convoy TarJak because at the point you see they were between 6 - 9 klicks out, and on a divergent course between 120 - 130 port AoB. At their speed, and course, and also because they'd already made one unexpected radical course change, I decided trying to outflank and re-approach them would likely fail. That happens of course :hulk: but that's life.:p

That makes sense. I'll definately give it a whirl next time I hti a situation like this.