Is there anything on how they used the radars?

[stellaferoxx]

Hi,

I can say I am quite an expert in all U-boat sims but somehow never got to the US subs. Now I have started a campaign in SH4 for the first time (and loving it!) and I am getting radars, surface and air. Is there any advice or material I can read how to use them properly on patrol, or do you just jump from sonar to SJ and SD back and forth?

Thx for you help

[Bubblehead1980]

Originally Posted by stellaferoxx

Hi,

I can say I am quite an expert in all U-boat sims but somehow never got to the US subs. Now I have started a campaign in SH4 for the first time (and loving it!) and I am getting radars, surface and air. Is there any advice or material I can read how to use them properly on patrol, or do you just jump from sonar to SJ and SD back and forth?

Thx for you help

I'll search my files when home and share, so you can read in depth, but here is a quick overview for now.

SD radar is air search only. Early models detected aircraft 7-10 mile depending on variety of factors such as height(lower plane is, closer it will get before detected) . In reality was mounted on an extendable mast so sub could raise it from 60 ft depth and sweep before surfacing. This is not modeled in stock but it is modeled in the mod Trigger Maru Overhauled (TMO) and other mods as well. Improved SD radar detects targets typically at 10-14 NM.

SD was in reality, not directional...so it only measured distance to contact. In the sim, it is unfortunately modeled incorrectly and does give a bearing and will give a map contact (if they are enabled)

Far as using it "properly" which I take to mean in historically accurate manner, well up to you but not much can do, its there, we dont have a separate display in the control room or conning tower display(UBI short changed us on that) so its use map contacts or just head the warning when reported and dive. In the FOTRS mod can turn the radar on and off, which is nice, but last I checked does not have the extendable mast, because of it is an either or situation from what I understand.

Some sub skippers kept SD off, just made periodic sweeps out of fear of the signal being detected.

SJ


SJ surface search radar typically picked up contacts around 9-11 NM depending on variety of conditions, such as range, size of target, the targets profile/AOB to the beam.

The early SJ radar only had the A scope display (green lines that "dance"), not the PPI scope, but UBI was lazy and included them both from started and thus far no one has figured out how to hide it without breaking the radar. To properly use, just ignored the PPI scope and use A scope if you choose.

Procedures varied but from understand , out of fear of being detected, giving a beacon to enemy forces, SJ was kept off during day time, with periodic sweeps every 15-30 minutes. At night, it was depended on much more obviously as it was a game changer at nights, especially as the night surface attack became the preferred method of attack by US submarines in late 1943 early 1944 and in reality, also for navigational purposes.


In the sim can run around with it on 24/7 if like until detect something. I do sweeps about every 15-30 mins on patrol then turn it off to use it properly and as I am currently working on introducing radar warning equipment to certain Japanese vessels in 1943 onward. They were based on German equipment and major warships received them, select number of destroyers and ASW escorts, aircraft as well in 1944/1945. Good habit to have as in future it.


SJ-1 radar came about in late 1943 and included the PPI display and improved performance. Can detect targets up to about 18 NM but typically around 12-14, of course depends on variety of factors. Use of the PPI display, showing positions relative to submarine really changes things, esp in a night surface attack situation.


Radars in SH 4 are poorly modeled but modders have improved them a lot. Possibly the best radar mod out is the 3D TDC and Radar Range Unit. This makes the SJ radar accurate, linked to the TDC (as it was in reality) and has a lovely 3D TDC modeled, which when the position keeper is activate on TDC, tracks the target, pretty cool to watch things unfold on the 3D TDC. Of course, if you play without map contacts, this is even more amazing as it makes your job a lot easier and more in line with history. I love it. The mod is in the downloads and is incorporated into Trigger Maru Overhauled.



Sonar wise. Your crewman assigned to the sonar can only hear within the ranges listed in the file, but when you man the station you can hear contacts much great distance, so always good to do a sweep. In reality the hydrophones on us subs could hear quite far, depending on conditions, but only had a certain effective range.


Subs could hear on the surface as had chin mounted sound heads and in the sim the effects of the subs engine noises, water, and speed are not modeled (ugh) so they are far too effective on the surface. . I've remedied this somewhat in TMO but still working on things.


So for sound, advice is , especially before radar do a sweep yourself to see fi hear anything. Continue to do even after radar as sometimes will hear very faint and distant ship noises which are outside of the SJ radar range, especially the early SJ radar.


I'll share some links here later when home.

[stellaferoxx]

Thx Bubblehead, that is already a lot. I am used to playing at 100% realism and with the FOTRS Mod. So the first thing I noticed is that you can't measure a ship's speed by its length passing a line. The length is not given.

I'd like to know more about the radar stuff. I want to be as authentic as possible (while having fun of course). Maybe any books you can recommend?

thx for taking the time to answer!

[propbeanie]

Look in the FotRSU Support / HowTo folder for CapnScurvy's "Using Radar_Sonar.pdf" file for something close to the FotRSU set-up. Bubblehead has the 3D TDC in his re-worked TMO, and that would be different. For the 'real' way to do it, try RADAR Operators' Manual, RADAR Bulletin NO. 3 on the USS Pampanito web site.

[Aktungbby]

American fleet submarines enjoyed a considerable advantage from very early in World War II, as they were equipped with basic radar from the first days of the Pacific conflict, and added more advanced units within the first year of the war.

presentation/18/ SD RADAR:
The earliest radar installed in the fleet boats was the SD air search radar. This was a very basic unit. Operated from the conning tower, the SD radar was only vaguely directional. It was capable of warning that a plane was within about 6 miles of the boat, but couldn’t really pinpoint a bearing, or give much in the way of information.

The main advantage it conferred was that it warned of aircraft in the vicinity, and could also indicate if they were coming closer, giving the boat time to dive and elude. The obvious problem was that it was still short range—6 miles can be covered in just over a minute at 300 mph—and was of very little use for surface searches. Getting away from enemy aircraft was important, but the priority was hunting down enemy ships, and something was needed to help with that goal.

Late in the war, SD was replaced by SV radar, which used a rotating directional antenna, and could give a range and bearing on the target. It was also capable of being linked to boat’s PPI, and had provisions for IFF (Identification, Friend or Foe) capability.



SJ RADAR:
The next major advance came with the installation of SJ Radar, beginning in mid-1942. Unlike the SD unit, the SJ was a directional radar, which could be used to sweep the surrounding sea for targets. The primary limitation on range was the height of the retractable mast, radar being limited to line-of-sight.

In the Pacific, the United States enjoyed a considerable advantage over the enemy. While the German u-boats were forced to spend most of their time submerged, kept down by the ubiquitous enemy radar on Allied ships and aircraft, the American submarines had the radar advantage over a Japanese fleet that largely lacked radar.

Japanese destroyers didn’t get radar until much too late in the war for it to do any real good. What was available mostly went to capital ships, and was mainly of a fairly primitive design, useful mostly for gunnery range finding. The fleet boats’ SJ radar was designed for search, ranging, and navigation, and was a much more advanced design.

In addition to conducting surface searches, the radar masts could also be extending above the water before surfacing, to check the area for enemy warships and aircraft. This was considerably more effective than using the periscope, particularly on dark nights.

PPI:
The next great advance in American submarine radar was the addition of a Plan Position Indicator (PPI) to the screen. This type of unit is common in even the cheapest small craft radar today, but at the time it was a revolutionary development.

The PPI superimposes a chart image on the screen, giving the operator and commander a much clearer idea of just where everything is. This could be extremely valuable when operating near a coast, since it was possible to match the chart on the PPI with the radar returns to get an exact position. (Radar waves bounce off of islands, too.)



PERISCOPE RADAR:
Late in the war, miniaturization had progressed to the point where it was possible to install a small radar antenna (ST) in the search periscope. This was used for obtaining an accurate range on a target. The sonar could also do this, but that required transmitting an audible “ping,” which could be heard by the target, warning them of the presence of a submarine. Most Japanese vessels were unable to detect the radar pulses, and so remained unaware until it was too late to elude.

The availability of these various forms of radar accounted for much of the effectiveness of the American fleet submarines in World War II. By giving warning of aircraft, radar allowed the boats to operate on the surface even in daylight, keeping the batteries charged, and greatly extending the distance that could be covered in a day. Even the SD radar could detect a plane beyond the visual range of the sharpest-eyed lookout.

As a surface search aid, radar again extended the visual range of a submarine’s lookouts. The antenna could be raised higher than a man could perch, giving it a broader horizon to search. And it could see through haze and fog, or on a moonless night, when a lookout might have trouble seeing the foredeck.

More importantly, because the submarines had radar, and the Japanese, for the most part, didn’t, it shifted the odds decisively in the direction of the submarines.

Of some intertest to the persnickitous: http://shipbucket.com/forums/viewtopic.php?t=7962

This is PAMPANITO (SS-383) in July of 1945, at the conclusion of a refit period at Hunter's Point near San Francisco. She is camouflaged in Measure 32/3SS-B.

PAMPANITO (like the class leader BALAO) was a "government built" boat, with two rows of limber holes and a portside anchor. PAMPANITO was launched with a 4"/50-caliber deck gun, but the July 1945 refit period removed this gun in favor of the newer 5"/25 wet mount. PAMPANITO also received two 40mm Bofors Mark 3 single mounts on the fairwater, and the aft end of the fairwater itself was shortened to reduce the boat's silhouette when running surfaced. The SV air search radar sits on a mast aft of the periscope shears, with the SJ-1 surface search antenna ahead of it, and the ST range-only radar on the forward periscope. APR-1 radar countermeasures stub antennas sit atop the periscope shears, and the usual DF loop (for underwater HF reception) hangs between the shears, suspended from the topmost brace.
PAMPANITO would survive the war to become a museum in San Francisco, CA.

[stellaferoxx]

Thx Propbeanie, this is what I need to dive into. The PDF helped a lot already. I am beginning to get an idea of discriminating between what was real and what is modelled in the game. I know too little about the US side of subs.

[stellaferoxx]

Originally Posted by Aktungbby

Of some intertest to the persnickitous: http://shipbucket.com/forums/viewtopic.php?t=7962

This is nice!

[propbeanie]

One ~HUGE~ difference between the real SJ and the game's version is land masses, or lack thereof in the game. If you would happen to see a PPI screen on a real sub back then, there was a lot of "clutter" that would show on the screen, and interfere with seeing ships. An experienced operator could navigate by radar, but an enemy combatant could hide in the "clutter" along the shoreline reflections. For the most part, not so in the game. Sonar is very similar in function in the game. "Land mass? What land mass? I don't see no shtinking land mass!... ??" and you can "see" a sonar line around most islands. Of course, the senior operator can hear a mackerel sneeze at 16 klicks...