Tactics for Merchant hunting (TWoS and Real Nav)

[Malwulf]

Hey all,

Quick question regarding different ways to go about finding Merchants. Let's say you have arrived in your patrol area and during a routine Hydrophone check you pick up a possible Merchant contact at long range. Exact range and course are unknown at this time, so catching up and overhauling the contact may be required.

Do you immediately adjust course and attempt to catch and sink the Merchant? Regardless of that fact that you may waste time trying to chase down this target? Or, do you wait in one area/continue searching until you find a contact that has a much more advantageous range, speed, and course? Maybe not as far away or their course is easy to intercept for example.

I have checked through various guides and have even done some research on this topic and how it worked in reality, but I would really like to get some thoughts from fellow sub-simmers. With that, my apologies in advance if this topic has already been discussed far too many times!

For reference, I am currently playing the latest version of SH5 with TWoS installed and Real Navigation enabled. Huge fan of immersion and using real world techniques/strategies.

Thank you all so much in advance!

[bstanko6]

Admiral Doenitz always looked at the hydrophone as a tool. He wrote books and procedures on this topic.

His idea was that no piece of equipment could replace the human being. The hydrophone was good, but you had to get "eyes on" as soon as possible.

Visual contact was key to the Uboat. This was however, a flaw. While Uboats relied on visual confirmations, and human intellect to conduct an attack, the allies were hardcore developing radar and other tools to fight them!

While watch crews were looking for targets, allies picked up the radar blip miles away and already moving in.

But in the end, Germans or Allies, you have to move in for that visual contact.

[XenonSurf]

Very well explained Bstanko6
I still have trouble to figure out if in bad weather situation my hydrophone will perform better at 40-50m instead of 17-25m which would be logical because a lot of surface noise is eliminated when you are deeper. However with my sonar guy at 0 additional promo points I cannot see any difference.

My system for the interception: First I use logic: Where could my target head towards? In SH5 this is a awkward judgement because it could go just anywhere, only land masses would be a reason for course changes, and it's never zig-zaging (which is not smart).

Then, if it's further away I will not try to make a direct surface intercept, but instead draw a guestimate angle to get closer and start a 4-bearing sonar tracking, if the different bearing angles are very small it means the target is fairly going away from me in the bearing direction, so I will go flank on surface in that direction for not losing contact.

Otherwise I will get quickly all data about course, range, and speed of the contact for a perfect interception by analyzing the different bearings and my triangulations after changing position. The 4-bearing method is a basic tool which gives incredible accurate results in SH5 without the need to ever visually see the target, also because, as said, contacts are fool enough to always head in a straight line. Did convoy captains not know about the 4-bearing method? Oh yeah they did know, they were not stupid, mind you, but I guess their attitude was: the shorter the convoy time lasts, the better for survival, so this could explain the absence of frequent course changes by convoys in the Atlantic or North Sea. AFAIK the Japanese convoys used different tactics. Also what I never see in SH5: convoy units which all in the prey of panic start heading in all possible directions once submarines are spotted. Suicidal for single units, but saving the big pack of the convoy.

Once close enough it's still time to identify the target before shooting and with my previous data I'm almost always in perfect shooting position. With or without real navigation in SH5, also in SH3/SH4, but not in SH1 where the AI is *really* smart, too bad that I can not draw a single line or angle on the map...I would easily pay the devs to modify this old game for me

Fact is that in reality this was not so easy and the hydro equipment not so powerful to always use this strategy, what's more: what is the value of perfect data gathering if the enemy radar is impeding you any good approach to the target (later in the war)? So skippers needed to invent some tricks out-of-the-book, but of course the 4-bearing was well-known to all skippers, hydrophone crews and navigators.

[derstosstrupp]

I second what Bstanko6 has said about the hydrophone. It was an auxiliary tool and nothing more. The boat’s place was on the surface. There is much more reliance on the in-game hydro than was truly done IRL.

Check out the link to a guide I put together for Wolfpack. I made it to look like a KM publication but it isn’t, but all the methods in there are historical methods of gathering shooting data. With Hitman’s permission I added the great charts from his SH3 GUI too.

Note that the 9000 m plotting is due to the limits of the Wolfpack environment. In SH5 you can plot as the real boats did since you have hull-down ships - keep the mast tips just visible and estimate the range based on that by eye while overhauling.

http://www.subsim.com/radioroom/showthread.php?t=241480