Jump to content
voltaicgrunt

Tinfish Mathmatics

25 comments in this topic

Recommended Posts

Players
165 posts
435 battles

After being charged down by a BB in my smoke and with no idea if he would get to me before my torps reloaded, I decided to do some addin up.

 

Knots and Km in same game is first problem, but I sorted that. At 30knots a ship covers approx 1 km per minute.

 

Torps go twice the speed, which makes predictions easier, so 60kn = 108Kmh = 1.8km/min = 30m/s.

 

A tinfish should cover 10nautical miles in close to 5 mins. But it doesn't, takes 90seconds.

 

Another way to look at it, 10KM = 5.3 nautical miles. At 60 knots, torps take 5.3 mins to cover 10km.

 

Is my math wrong, or is the mathematical perspective of this game skewed?

 

 

Edited by voltaicgrunt

Share this post


Link to post
Share on other sites
Players
13 posts
2,560 battles

The games math is fucked up regarding the correlation between distance/range/time. If you look at you after battlereport, your sailed distance is often way more than is possible in 15 mins or less.

Edited by Djoller

Share this post


Link to post
Share on other sites
Weekend Tester
1,197 posts
9,304 battles

Yep it's not really possible to do 1 km every 10 seconds with a Bismarck. :teethhappy:

 

Edited by Srle_Vigilante

Share this post


Link to post
Share on other sites
[DUDES]
WoWs Wiki Team, Privateer
1,795 posts
17,386 battles

Torps go twice the speed, which makes predictions easier, so 60kn = 108Kmh = 1.8km/min = 30m/s.

 

Those numbers are correct. The only difference is the boosted speed in-game, because actual knots would have been to slow for a shooter type game. These boosted speeds apply to all large moving object in the game (ships, torpedoes and planes - bullets behave differently). Unfortunately I dont know the exact value how much faster the in-game knots are compared to the real knots.

Share this post


Link to post
Share on other sites
[SYTHE]
Players
618 posts
6,581 battles

IIRC (and it's been a while), game knots are six times faster than real ones.

As others have noted, speeds given in m/s scale differently to speeds given in knots. I think they are still sped up, but not as much.

 

Ships are also something like five times too big (check out the 1km-long star destroyers^W^Wbattleships), but that's probably less of an issue for what you're trying to calculate.

Share this post


Link to post
Share on other sites
Players
1,091 posts
2,423 battles

I choose not to think about it anymore. I'm a navigator irl and thus know a fair bit of convering nautical miles, degrees, minutes and seconds to km and m (yes, all distance measurements).

But what they use ingame baffels me. Best not to think of it I guess.

  • Cool 1

Share this post


Link to post
Share on other sites
[DUDES]
WoWs Wiki Team, Privateer
1,795 posts
17,386 battles

Ok... I did a short training room session. I used the torpedoes of my Leningrad: they can travel 8 km at a speed of 60 kn. On average they took 51.08 s to the edge of their range. This means 60 kn are 156.6 m/s or 563.8 km/h in-game. This combination of digits looks arbitrary and really weird...

 

 

Edit: Derp!

 

Edited by Z_OnkelE

Share this post


Link to post
Share on other sites
[SYTHE]
Players
618 posts
6,581 battles

Ok... I did a short training room session. I used the torpedoes of my Leningrad: they can travel 8 km at a speed of 60 kn. On average they took 51.08 s to the edge of their range. This means 60 kn are 156.6 m/s or 43.5 km/h in-game. This combination of digits looks arbitrary and really weird...

 

That's almost exactly 5x reality. So looks like knots are 5x too fast in game, not 6x as I had understood.

Share this post


Link to post
Share on other sites
[BABBY]
Beta Tester
1,596 posts

I think it's that the ships are scaled up (go near some coastal buildings found on most maps to witness the attack of the 5000ft destroyer) and the speed is a result of that.

Share this post


Link to post
Share on other sites
Players
1,091 posts
2,423 battles

 

That's almost exactly 5x reality. So looks like knots are 5x too fast in game, not 6x as I had understood.

 

I don't understand this. How is that 5x faster than real?

60kn x 1.852 = 111.12km/h

So 45km/h is less than half the speed of 60 real knots.

 

But apparently in game 1 knot equals to 0.725km/h.

Share this post


Link to post
Share on other sites
Beta Tester
1,739 posts
1,782 battles

Ok... I did a short training room session. I used the torpedoes of my Leningrad: they can travel 8 km at a speed of 60 kn. On average they took 51.08 s to the edge of their range. This means 60 kn are 156.6 m/s or 43.5 km/h in-game. This combination of digits looks arbitrary and really weird...

 

 

I don't understand this. How is that 5x faster than real?

60kn x 1.852 = 111.12km/h

So 45km/h is less than half the speed of 60 real knots.

 

But apparently in game 1 knot equals to 0.725km/h.

Small calculation error here... according to Z_OnkelE's test, the torp speed is not 43.5 km/h but 563.76 km/h ... that is around x5 the normal speed. 

Share this post


Link to post
Share on other sites
[SYTHE]
Players
618 posts
6,581 battles

 

I don't understand this. How is that 5x faster than real?

If the torp covers 8km in 51 seconds, 8000/51 = 157 m/s.

Divide this by 60 to give 1 knot = 2.61 m/s, in game world.

In reality, 1 knot = 0.51 m/s.

2.61 / 0.51 = 5ish. (it's actually a bit over, but either that's down to measurement error or WG haven't used a nice round number)

 

If you prefer to work in km/h, then since there are 3600 seconds in an hour,

8 * (3600/51) = 565 km/h (not 44 km/hr as you said). Divide by 60 and 1 knot = 9.4 km/h

In reality, 1 knot = 1.85 km/h. 9.4 / 1.85 = 5ish.

Share this post


Link to post
Share on other sites
[SYTHE]
Players
618 posts
6,581 battles

I think it's that the ships are scaled up (go near some coastal buildings found on most maps to witness the attack of the 5000ft destroyer) and the speed is a result of that.

 

The ships are scaled up, but that doesn't have any bearing on the speed of things if we're working with "real-world" metres.

IF the ships are scaled by the same factor as the speeds (which I'm not sure about), then one could argue that another way of looking at it, which is nicely consistent but perhaps harder to gets one's head around, is simply that metres in the game are five times larger than usual except when reported to the user, and that islands are tiny :-)

Share this post


Link to post
Share on other sites
[DUDES]
WoWs Wiki Team, Privateer
1,795 posts
17,386 battles

2.61 / 0.51 = 5ish. (it's actually a bit over, but either that's down to measurement error or WG haven't used a nice round number)

 

... and of course errors of my time measurement, even though I used a median and not the value of only one set of torpedoes.

 

 

Just a heads-up: due to the numbers I got from my experiments, I think I will do another test with a ship itself. I suspect they scale differently than ships in terms of speed actually.

 

For convenience reasons I will use the Tachibana. She can go 30 kn and agile enough to get the manoeuvres and precise positioning done. The plan is to use the map squares to determine the distances and the do a normal "time needed for X lines past".

 

The only uncertainty in this case: the information about the distance between each line. As far as I remember from one of the older minimap mods on the map Islands (T1+T2) the lines have a distance of 2.4 km to each other. But this can be reevaluated afterwards.

 

Edit:

The lines on the map Islands should be 2.4 km apart according to this screenshot (taken 24th of September this year)

20160924_IslandsMinimap.jpg

 

Edited by Z_OnkelE

Share this post


Link to post
Share on other sites
Players
1,091 posts
2,423 battles

 

Small calculation error here... according to Z_OnkelE's test, the torp speed is not 43.5 km/h but 563.76 km/h ... that is around x5 the normal speed. 

 

Ah, that explains it. I did not check his calculations.

Share this post


Link to post
Share on other sites
Beta Tester
324 posts
2,096 battles

if I recall the speed scale factor for torpedoes and ships from a Q&A is 5.22. Ships are scaled to be approximately twice there original size.

Edited by DominusEdwardius

Share this post


Link to post
Share on other sites
Players
165 posts
435 battles

I did this exercise because I'm crap at torping. The math confused me because ships/torps in knots, distances in Km and I could not get the numbers to match.

 

Once forum explained everything x5 or x6 I stopped bothering about the numbers, I now use what I think of as the rule of halves.

 

Ship does half speed of torps (approx).

 

Ship sailing 90 degree vector at 10km. Offset aim is 35 degrees (3x width of narrow spread on a Mahan). The offset halves for every angle of degree for a ship approaching/fleeing. EG. BB heading inbound at 45 degrees, aim point is 17.5 degrees off track. Fleeing at 45 degrees, 35+17.5 = 52.5 degrees.

 

Very useful for deciding how much lead adjustment to use for manoeuvring ships.

 

Ship covers half the distance of torp, with 10KM torps and enemy heading straight towards you at 0 degrees, Theoretical max range shot is 10km + 2.5km = 12.5km.

 

For stern chasing shot, it doubles, 10km - (30/2)*2 = 5km.

 

Figures are approx because working on 60kn torps and 30 kn ship, but it's close enough for Govt work. You can fudge the rest on the fly, and torp spread will help.

 

WHY BOTHER?

I am using this successfully to set up torpedo ambushes in 3 situations.

First, when you have ship detected but he disappears behind islands, etc.

Second, using minimap I can get an accurate prediction.

Third, as stated, to adjust from computer predicted track for manoeuvring ships.

 

Example.

Soon after spawn, when enemy is heading for their chosen engagement areas, I can time shots into areas I know they're going to go with some degree of accuracy. You know the map, you know there are places the enemy has to sail initially, using this rule I can put torps into those areas as they pass through.

 

This is NOT the best way to torpedo, but it is an extra tool and I find it very effective because early in the game, no one is expecting torps, and they aren't dodging.

 

It's like Arty in WoT taking blind shots at well travelled routes, only with a little more science.

 

Edited by voltaicgrunt

Share this post


Link to post
Share on other sites
[DUDES]
WoWs Wiki Team, Privateer
1,795 posts
17,386 battles

Ok! Here are the value for a full speed (no flag, no boost) Tachibana in a straight line. The method worked according to the following layout:

SpeedMeasMethod.jpg

I started full speed near a corner of the map squares and sailed parallel to one of the North-South lines. In this way it was ensured my ship only travelled the distance equal to the edge length of the squares. The time was taken for the start and the end when the tip of the ship arrow was on the lines (you can also see an example of the timestamps in the top right corner). I used 5 squares as a distance because: a) precision, b) referring to the screenshot in my earlier post, the distance between the first and fifth line is exactly 12 km.

 

The Tachibana needed 147.94 s for those 12 km (check the picture above, too) at her 30 kn (30.1 kts according to the game UI). This leads to a speed of 81.12 m/s or 292.02 km/h. If you recall earlier values for the torpedoes, ships seem to have slightly higher m/s per kn-relation than torpedoes! I absolutely understand if anybody is baffled over the time objects in this game need to travel distanced. These numbers are indeed fishy!

 

 

TL;DR:

torpedo speeds relate to 2.6 m/s per 1 kn in game (or 9.40 km/h per 1 kn in game)

ships speeds relate to 2.7 m/s per 1 kn in game (or 9.73 km/h per 1 kn in game)

 

Edit: Derp!

Edited by Z_OnkelE

Share this post


Link to post
Share on other sites
Beta Tester
1,739 posts
1,782 battles

 This leads to a speed of 81.12 m/s or 22.53 km/h

Again, m/s to km/h is (m/s * 3.6) = km/h, so 81.12 m/s = 292.03 km/h

  • Cool 1

Share this post


Link to post
Share on other sites
[DUDES]
WoWs Wiki Team, Privateer
1,795 posts
17,386 battles

Again, m/s to km/h is (m/s * 3.6) = km/h, so 81.12 m/s = 292.03 km/h

 

Haha! Initially I did it right this time and then I corrected it to relate to the older one :teethhappy:

 

But absolutely good derp from my side :fishpalm: . Corrected all values above!

Share this post


Link to post
Share on other sites
Beta Tester
1,739 posts
1,782 battles

Rest of the calculations is correct however. 1 kn = 2.6 m/s is the right number for torpedoes.

Share this post


Link to post
Share on other sites
[SYTHE]
Players
618 posts
6,581 battles

, ships seem to have slightly higher m/s per kn-relation than torpedoes! I absolutely understand if anybody is baffled over the time objects in this game need to travel distanced. These numbers are indeed fishy!

 

torpedo speeds relate to 2.6 m/s per 1 kn in game (or 9.40 km/h per 1 kn in game)

ships speeds relate to 2.7 m/s per 1 kn in game (or 9.73 km/h per 1 kn in game)

 

 

This small difference is very probably experimental error.

Share this post


Link to post
Share on other sites
[DUDES]
WoWs Wiki Team, Privateer
1,795 posts
17,386 battles

This small difference is very probably experimental error.

 

Maybe. I also checked the 30.1 kn version and the difference was not noticeable, thus I excluded that discrepancy. But 2.6 to 2.7 looked a bit too much for just rounding errors, hence I did mentioned them separately.

Share this post


Link to post
Share on other sites
[R_N_G]
Players
37 posts
12,487 battles

Check out

wiki.wargaming.net/en/Torpedoes_(WoWS)#Reaction_Time

... says 2.6 for torpedoes,

or

http://forum.worldofwarships.eu/index.php?/topic/65200-fubuki-vs-benson-darkys-ultrakurzer-guide/page__pid__1392187#entry1392187

... says 2.6854 for torpedoes, but I don't know where he gets that numer from?!

Edited by Utlieov

Share this post


Link to post
Share on other sites
Beta Tester
324 posts
2,096 battles

If memory serves correct, 2.6 (or was it 2.61) was the value confirmed by Wargamming (eventually), the 2.6854 is from the HUD which misrepresents the torpedo speeds I do believe.

Share this post


Link to post
Share on other sites

×