Sonar and radar

[Zero Niner]

Here's a weird "feature": I was surfaced, running at about 9 kts in a P=class. Then the sonarman calls out contacts and I see a few grey and blue lines. It was an enemy convoy, and I was still surfaced.
I'm no naval person but surely passive sonar doesn't work when surfaced?

I'm using GFO 1.1.

[fireftr18]

Originally Posted by Zero Niner

Here's a weird "feature": I was surfaced, running at about 9 kts in a P=class. Then the sonarman calls out contacts and I see a few grey and blue lines. It was an enemy convoy, and I was still surfaced.
I'm no naval person but surely passive sonar doesn't work when surfaced?

I'm using GFO 1.1.

It depends on the sonar set you have. I'm not sure about the P-Class. The sonar set of fleet boats had a head on the bottom of the hull so that passive sonar is useful while on the surface.

[propbeanie]

The Porpoise did too, but they are just a ~pinch~ overly sensitive. You really shouldn't be able to hear much at 9 knots besides the noise your hull makes going through the ocean, but oh well... The watch crew will make up for it here in just a little bit probably...

[CapnScurvy]

Originally Posted by Zero Niner

Here's a weird "feature": I was surfaced, running at about 9 kts in a P=class. Then the sonarman calls out contacts and I see a few grey and blue lines. It was an enemy convoy, and I was still surfaced.
I'm no naval person but surely passive sonar doesn't work when surfaced?

I'm using GFO 1.1.

If the mod is designed correctly, there is no reason for a newer American sub to not detect a target while surfaced. Unlike the German U-Boat's, most later U.S. Fleetboats had their Sonar/Hydrophone equipment on the bottom of the hull:





The Germans (and the earlier American class subs) had their equipment on the deck....requiring the sub to be submerged in order to operate. Here's an S-Class subs Hydrophone receiver:




An early Porpoise Hydrophone receiver:




Later in the war, the Porpoise and other early sub classes got the hull mount versions, allowing surfaced reception. The only drawback was the already mentioned interference from the subs own speed that created issues for the equipment. A 9knt speed should not produce detection. However, a surfaced American sub, at the correct time period....at a lower speed, will work.

I'm planning on making sure the Sonar/Hydrophones work as expected for the different subs with the FOTRS Ultimate mod. I'm even going to add the ability to have an S-Class boat purchase, through an upgrade, a Hull Mount receiver...probably towards the later stages of the subs life cycle.

[max-peck]

Originally Posted by CapnScurvy

An early Porpoise Hydrophone receiver:

Oh so that's what that is.

I knew about the S Boats having a deck mounted hydrophone receiver
But I did not know the early war Porpoise Boats also had one

I tend to start all of my careers in early 1942 in a Porpoise, and always wondered what that thing on my deck was
I just never made the connection.

Good info - thanks Capn

[Zero Niner]

I have another question: I have the option of installing the SJ or SJ-I radar on my boat. I suppose the SJ-I is an improved version of the SJ?

[CapnScurvy]

Originally Posted by Zero Niner

I have another question: I have the option of installing the SJ or SJ-I radar on my boat. I suppose the SJ-I is an improved version of the SJ?

Yes, the SJ-I usually has greater detection capabilities (greater maximum range, better detection probability). Least it should with most mods and the stock game. But, there are mods that don't address the Radar at all....without giving much thought in accuracy, or authentic characteristics.

It's like the early subs that should only produce hydrophone use while your submerged. Some of them don't do that. You'll get hydrophone use no matter which position your sub is in (besides the reason of not getting it while the target is traveling at less than half its MaxSpeed). It's all kind of confusing for a player who doesn't know what to expect, yet knows what the game does, and believes the behavior is normal.