Determined intercept

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:





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:



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.