Question

[hector]

Hi
If i am submerged and attacking a convoy,(U Boat missions 1943)i will always be spotted if i increase my speed beyond "ahead slow"(iirc) and the convoy will split in all directions.Do the merchants have sonar or is it something else.?

Thanks,

Hector.

[Zantham]

If there are any escorts in the convoy then they may hear you on the sonar, but I haven't discovered any merchants with sonar yet. Sometimes I go flank at PD and they don't know I'm there. Just make sure you dont have anything sticking out of the water. If the seas are rough you can sometimes broach the surface slightly, they can see that too.

[hector]

Hi Zantham,
Thanks for the quick reply to something that is really puzzling me.I understand about them spotting the periscope and so on as i am a player of SH4&3 but thats not it.I cant think what else it may be.
The mods i am using are Enviroment 4,Poul sounds,diverate and enable the Type18 early.(Thanks )

Hector

[Fincuan]

Most of the merchants receive hydrophones in 1942-1943, so it's entirely possible they hear you.

[Zantham]

Originally Posted by Fincuan

Most of the merchants receive hydrophones in 1942-1943, so it's entirely possible they hear you.

Fincuan, I'm aware some of the Japanese merchants may get hydrophones, which would affect the US campaign, but have you found if US/Great Britian allied merchants get hydrophones, which would affect the uboat campaign? I haven't run into any merchants yet that have detected me underwater, but I'm not past 1943 in the uboat campaign either.

[Fincuan]

I haven't either been detected underwater by merchants in my U-boat career(only October 1943), but then again I've only seen Liberty Ships, T3 tankers and Small Old split superstructure freighters, none of which receive hydrophones. I haven't checked what kind of ships the game spawns in US convoys, but I imagine it would be entirely possible that a ship or two(one of the Jap ships) with hydrophones could be spawned. I've modded merchant hydrophones out of my own game btw, since I highly doubt they were that common in real life.

[hector]

I decided to start a new career in 43 with the Type IX-D2.I was able to creep into the first two small convoys without being picked up,infact,i could have used Flank speed and still wouldnt have been spotted.The third convoy was different,the T3 Tanker started to get agitated at over 9000yds so i assume he heard me.This made me think back to my original post and i remembered there was always a T3 in the convoy and possibly a "Liberty ship" when i was heard above "ahead one third".

Maybe someone could point me in the direction of the allied merchants so i could check if they have sonar and then hopefully remove them.

Thanks,

Hector.

[Penelope_Grey]

If I had to conjecture, I would put it down to one of the following... 1. they can see your periscope. or 2. they can actually see your sub.

This happened to me once in a fleet boat while attacking a Japanese task force, on a clear clear day if you are close enough to the surface they will attack you because they can see your conning tower/deck plates. I had the Japanese escorts machine gunning into the water to try and get me. I kid you not.

SH4 appears to have an allowance to spot you while at shallow depth, something SH3 does not have.

[hector]

Hi PG
Thanks for your input on this one.While i understand what you are saying,the T3 Tanker started evasive action at just over 9000yards which seems a bit far to see me under the water.I still think i am being heard as all seems fine if i stay at "ahead one third" speed or "silent running" but i will watch some more and see what happens

Thanks,

Hector

[Fincuan]

Neither T3s or Liberty ships have sonar at any stage of the war and even Bungo Pete can't hear you from 9000 yards away, so you did nothing wrong

At best they usually pick you up on their hydrophones from about 4-5 km away, and that's when going flank. The ships' sensors are defined in Data/Sea/shipname/shipname.sns. It might look for example like this(note that this ship receives a better hydrophone in January 1944):

[Sensor 1]
NodeName=O01
LinkName=M_Visual
StartDate=19380101
EndDate=19451231

[Sensor 2]
NodeName=H01
LinkName=NULL
StartDate=19380101
EndDate=19421001

[Sensor 3]
NodeName=H01
LinkName=Type3-M1P
StartDate=19421001
EndDate=19441101

[Sensor 4]
NodeName=H01
LinkName=Type3-M2P
StartDate=19441101
EndDate=19451201

Hydrophone is node H01. When you replace the bold parts(merchants seem to have Type3-M1P or M2P) with NULL, no more hydrophone. Alternatively, and only if you use TMO 1.5, I could put my files up for download since I've already modded my merchants. They won't work without TMO because they use some of the mod's sensors.

[hector]

Fincuan,
Thanks for that great info and i will have a look through those tomorrow and hope i can work some magic with notepad.Thanks also for the alternative help but i dont use TMO 1.5.

Thanks mate

Hector