Manual TDC speed figuring

[Rockin Robbins]

Originally Posted by DrBeast

I use the simple 3min 10sec rule: jot down the position of the ship on the map, start the watch, and put down the next mark after exactly 3 minutes and 10 seconds. I then measure the distance traveled in Km, multiply by 10 and hey! presto, I have the target's speed in knots. Being a European, I don't bother with feet, hands, brows, or any of that jargon: it's metric system for me. :p

*DrBeast sits back and waits for Rockin Robbins to come charging in

I always pause and zoom in completely when I'm jotting down the marks and measuring, that could help a bit.

Charrrrrrrrrrge! In human measurement terms, use the 3 minute rule. Distance traveled in nautical miles (the knot is nautical miles per hour. That's a CLUE!!!:rotfl times 20 is speed in knots.

If they have the sense to use knots, you'd think they would have the sense to use sensible units all the time instead of mixing them all up. And hey, these are American boats. We'll have none of that kilohertz stuff here, it's kilocycles!!!! Ya see, that term actually MEANS something. All those Europeans HATE words that actually mean something... Maybe that's why they speak all those foreign languages? OUCH! Onkel Neal, he hit me!

[DrBeast]

Originally Posted by Rockin Robbins

Charrrrrrrrrrge! In human measurement terms, use the 3 minute rule. Distance traveled in nautical miles (the knot is nautical miles per hour. That's a CLUE!!!:rotfl times 20 is speed in knots.

If they have the sense to use knots, you'd think they would have the sense to use sensible units all the time instead of mixing them all up. And hey, these are American boats. We'll have none of that kilohertz stuff here, it's kilocycles!!!! Ya see, that term actually MEANS something. All those Europeans HATE words that actually mean something... Maybe that's why they speak all those foreign languages? OUCH! Onkel Neal, he hit me!

*DrBeast hides the fly-swatter behind his back
No I didn't! :rotfl:
When it comes to terminology, I must admit I have a fair advantage over you anglo-saxons. Many words derive from greek, and being greek sure helps me understand words that'd make you guys dig up a dictionary in sheer frustration

I hope I remember the nm rule this time...I keep seeing it time and again and I always forget it...maybe I should engrave it on the monitor..."3 minutes, nm x 20 = knots"...there, that should do the trick!

[looney]

How do the yards work then?? I'm also a metric person but when playing US sub I try to work in knots.

[Raptor1]

Holy thread bump of eternal bumpiness!

Anyway, 1 knot = 2,025.372 yards/h, Mesa think

[looney]

That makes sense.. i noticed 10k yards = 5nm (roughly)

I now understand why the 3min rule works

That's what the search function is for not?

Sup fellows...

First post here... I've been a fan of sub sims for some time now...

It all started roughly with Jane's 688(i), then more recently Sub Command, Fast Attack and finally Dangerous Waters... now I'm on to SH4.

Having played those games, I still didn't dominate them completely... there are details that still elude me... lol

One thing is all the jibberish units talk... being portuguese I'm accostumed to meters.... seeing feet, yards, knots, nautical miles.... it's just mind blogging...

So every time I start in a different game the fist thing I always set up is a conversion chart... everything to meters... so I can have a rough idea of what I'm doing...

Cause if someone says a ship is 4000yards away I don't have that instinct to know if that's far or near...lol.. so if someone says it's 3,6km away... I can know how far it is mentally... don't know if this makes sense to you...

[Sailor Steve]

WELCOME ABOARD, kramxel!

I'm American, but I'm one of the many who thinks just like you...well, just the opposite, in one sense. I still think in yards, feet and miles, but when I play SH3 I always use metric.

One thing that will make it simple to understand is that when the International Ordinary Hydrographic society standardized the nautical mile in 1929, they made it metric. A nautical mile is exactly 1852 metres. The United States didn't adopt it until 1954, since this comes to an odd number, as Raptor1 pointed out.

Yes, it is confusing, but can be simple to execute. A yard is 0.9144 metres, which makes a metre 1.0936 yards. As you can see, the two are close enough that for measuring fairly short ranges you can do it in your head. For longer ranges it falls apart. The nautical mile is used for long-distance measurement, and the knot for speed, because a nautical mile is one minute of arc (1/60 degree), or 1/21600 of the distance around the earth.

These should help explain it further:
http://en.wikipedia.org/wiki/Nautical_mile
http://en.wikipedia.org/wiki/Minute_of_arc