question about torpedo depth & under the keel shots.

[gutted]

In SH3, the norm was to set the depth of the torpedo ~2m more than the listed draft of the ship for a good keel shot so they will pass under the ship.

.ie
7m draft = 9m torpedo depth.

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In SHIV with the mk.14's it's possible they'll run up to 3m deeper than what you set them for.

so:
7m draft = 6m torpedo depth ( 7m draft + 2m under, -3m for the variance in depth). so in essence 1m less than the listed draft.


am i correct in this assumption? aren't we still trying to get them ~2m under the ship?

when if first started playing SHIV some years ago, i would set 2m more like i did in SH3 but go so many non-triggers, that i quit using them and just went for contact. wasn't till much later that i found out about the depth problems. but lately i've been having alot of calm seas, and am looking to finally start trying out these magnetics again. but i see threads where people are saying to set them 10' feet (3m) less then the indicated draft.

so

7m draft = 4m depth.

wouldn't that not ever have the torpedo pass just under the ship for a magnetic keel shot? wouldn't it always still hit the ship?

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so if you were using imperial measurements (which i dont)... there's a 10' possible depth variance. we want it to be within about 5' under the ship.

20' draft = 15' torpedo depth. yet.. i see threads where peopel say to use 10' for this example. why set mag's if you aren't even trying for an under keel shot in this case? with a 10' setting you're either going to hit the ship right in the middle.. or you are going to hit it squre on it's keel... never underneath the keel where you really want it.

or am i wrong?

[gutted]

just did some extensive testing (note: im using TMO). Loaded up the nav training mission with manual targetting off (for speed). turned the ship to point at the T3 tanker and saved. Also note, i use metric.. so you imperial skippers will have to convert it. (3m = around 10 feet).

For each test i fired 4 fish set for contact/mag, and in each test 1 of them blew before ever reaching the tanker (again.. im using TMO mod).

T3 = 10.7m draft.



1st test:
10.7m depth = All fish sailed underneath harmlessly

2nd test:
9.7m depth = 1 mag detonated, rest pased by harmlessly.

3rd test:
8.7m depth = 1 mag detonated, 2 impacted.

4th test:
7.7m depth = 3 impacts

5th test:
9m depth = 3 mag detonations underneath, ship cracked in half.

6th test:
8.7m depth = 3 impacts

7th test:
9.5m depth = 1 mag detonation, 2 sailed by

8th test:
9m depth = 1 impact, 2 mags underneath... ship cracked in half

9th test:
9m depth = 3 mags, ship cracked in half


so my findings are....

just shy of 2m less than then the listed draft.

in this case 10.7m draft, just less than 2m would be ~9m depth.

in perfectly calm seas probably exactly 2m less than listed is ideal. heavier seas, you'd probably set it 3m less than listed im guessing.


one thing of note.. there's a huge difference in torpedo's striking near keel, and blowing up just underneath it. the ones that impacted near the keel didn't blow nearly the size of the hole as the ones that blew up just underneath it (as seen from the Free Camera). lastly, the distance from the bottom of the ship you need to be and still get a mag det. is MUCH less than in SH3. you need it to pass right underneath the ship really close. in SH3 you could be up to 2m below the ship and still have it go off... not here.

so to wrap it up:

From now on, if i have really calm seas i'll go for a mag det with 2m less than listed draft. Anything more than really calm seas, and you can expect at minimum 1 in 4 torpedos to blow prematurely when set for magnetic in TMO (even more in rougher weather).

[ETR3(SS)]

An interesting test to say the least. Try it again in 44. The problems with the MK 14 torpedo are fixed then, or at least mostly worked out. The advice of the day (and here in game too) was don't use magnetic and set your fish shallow. Also try your test in a mission that you created so you can get the ideal control environment.

[Rockin Robbins]

I've found that the mag exploder isn't reliable no matter where the torpedo goes. I usually set it, but go for the impact explosion. Most everything sinks with two hits, 1/4 of the way forward of the stern and 1/4 of the way back from the bow, anyway.

Also the visual damage model is not related to the actual damage the target sustains. I've sunk lots of targets showing no visual damage at all! I've had some with a couple of huge holes just hang out forever and need another torpedo to sink them. Eye candy lies a lot!

In the real world, both the US and Germany concluded that their magnetic exploders were garbage and switched to an impact only strategy. Both ended up with under performing torpedoes with an explosive charge gauged to sink targets when exploded under the keel to break the back of the target. Both compensated by just shooting more torpedoes.

The US tried to compensate by introducing the Mark 16 torpedo with a larger explosive charge, but the Japanese ran out of fight before they could reach the field in quantity.

[Matthiu23]

Wow that sounds like a lot of difference.. water has a massive deterrence for explosive power so I would want it exploding under keel but as close to the ship as possible. There's an armor layer but you just need to get under that. Do that and the ship is taking on water big time. I heard its a good idea to set them 5 feet under keel but I had so many sail under the ship I said screw it and started setting for roughly 1.5- 3 ft ABOVE draft.. I wouldn't want to set it anything like 2 meters below or above. That's just not an accurate shot. And even setting it at draft can make them sail below the ship. There's also the issue of duds so in that case id rather it hit the bottom of the ship under the armor. My comfort zone is 1.5 feet above draft to I guess 2.5 ft.. that being said I guess 2 feet above draft would work great. This guy said 1.5 meters was perfect but I don't know. That's just too much variance. As i said, I want it blowing up touching the very bottom of the ship if possible. I don't want to be aiming at the armor layer. The ship in the torpedo sub school level is a good practice target. I was downing it in two torpedoes consistently and it calls for 3-4. Supposedly a well placed shot can take down any ship in one shot. It would probably take a few minutes for it to sink like that so one perfect shot to the bow and one center will do it. I was also doing it on 100% realism. Side note. You can get the crew to estimate speed by giving them a couple range measurements at about a minute apart. I noticed a lot of people are saying the crew won't do it but this is how I eventually was able to get them to do it. No more manual distance mapping to find speed. You don't even need to run the chronometer. I thought it had something to do with that but it doesn't. I want to be able to do everything with the sonar and mapping but I digress. Again my recommendation would be .7 meters above draft or about 2 ft. Actually I just read the guys experiment again and it looks like going slightly higher may work better but one time one of them impacted so let's go ahead and say 4 -4.5ft above is perfect? It's just interesting that the recommendation is 5 feet below but almost 5 feet above is what you want. Interesting about the 10' depth variance, that explains inconsistent results.

[Aktungbby]

Matthiu23! Like Rockin RoBBY I go for two contact shots generally set 2 meters above stated keel depth. That is because in SHV at least, some of the keel depths are not accurate as stated and the eels run under. The Ranger tanker shows 6 meters but only hits at three meters...