Boat Speed

[Subzero]

Would someone please be kind enough to explain to me the different speeds and when they should be used. ie Ahead one third (if thats not self explanatory), ahead flank etc.

Many Thanks

SZ

[gouldjg]

Ahead slow = fuel economy rate i.e. more milage but longer to get there.

What many players do not realise is when underwater, they try to fast turn a Destroyer by going left full rudder at flank speed without realising that their turn will take much longer than a lower speed turn.

Flank speed is for either chasing down a fast enemy or when actually running away during the last few seconds before Dc's land in your location. Flank is also good for finnishing of a tight turn so you can get on blind side of DD faster.

Flank is not good for out turning a DD when he has a lock on you. You should always slow down and save your flank as a last secinds tactic. The same goes for the reverses.


Take a tip from me and hit reverse for a few seconds to bring down your speed and while setting rudder to the direction you want, then as you beging to turn, hit flank speed and gradually set it back to normal or silent running. You will notice tighter turns and when you do this whilst being attacked you will also notice better DC evasion.

It would help to do a google search on Silent Hunter 2 tactics.

When I played that game, there was a lot more talk on evasion tactics. I presume most players already know this stuff and more but we still get the few noobs who have yet to discover the basics.

[jherdt]

For what it is worth, I've found 1/3 speed on the surface a nice trade off between fuel economy and length of time to get there. When I first started the game I used Standard most of the time, but this consumes too much fuel to stay on station for any length of time.

r/ Jim

[Floater]

What many players do not realise is when underwater, they try to fast turn a Destroyer by going left full rudder at flank speed without realising that their turn will take much longer than a lower speed turn.
No, it's the other way around, and is modelled as such in SH3. Faster speed means faster turns. It's easily tested - you can order a hard rudder, bang up TC, and see how your turn rate changes when you change speed.

[gouldjg]

Is it not a generel rule to start your turn at a slower speed and then half way through turn you should then go flank to get tighter turns.

It seems that way to me but maybe I am mistaken.

I was sure it is this way to make tighter turns though. No wonder I am still getting bloody hit.

[Floater]

It doesn't matter whether you're starting a turn, or partway through it - the effect is the same. The faster you're moving, the greater the water pressure differential at the rudder, and hence the more energy provided to turn the boat. As far as I can tell - I'm no expert here on the exact physics- this is pretty accurately modelled in SH3, and also was in SH2.

Downsides: (1) of course, by going faster, you're making more noise, and (2) the mechanics of turning the boat actually slow you down somewhat for the same reason that travelling fast speeds your turn.

It works the same way for the dive-planes too. The faster you're travelling, the more effective the dive-planes are. That's why, when you order a crash dive, the Chief orders ahead flank.

[jmr]

Not sure if this is the right term but couldn't U-boat skippers use differential power from the engines to turn faster?

[Soviet_Warlord]

Not sure if this is the right term but couldn't U-boat skippers use differential power from the engines to turn faster?

yup but the game doesn't have the differential power feature :x

[coronas]

Experience says me than economic speed is 1/3. I`m wrong?

[gouldjg]

Now I am confused and feeling pretty stupid here.

So Floater

Lets say we have 2 uboats heading north at flank speed.

The need to change to head east asap.

sub A Starts his turn and sustains it at flank speed all the way through.

Sub B Starts his turn (full rudder) however decreases speed as fast as possible also until sub reaches about 2 knots then speeds back up again equally as fast as possible.


Which sub will face East faster?


I would have thought that the flank all the time sub would make a wider turn and thus take longer.

I am so confused now.

Did they not do a similar move in Red October or am I missing something here. I am sure this was counted as good advice for sh2 game.

[Floater]

Gouldjg, I've not a hydrophysicist, so I'll leave this one open. I've explained how I think it works, and you seem to understand well what I'm saying, but now I'm wondering if I'm wrong. :o

You know what I reckon, though? It's going to boil down to parameters, such as the mass of the submarine (and hence its inertia), the surface area and profile of the rudders, and stuff like that. Loads of variables. It's not going to be a straightforward answer, even if we can get hold of the knowledge we need to solve this one.

I'll add that both SH2 and SH3 model faster turn rates for faster speeds, and both sims have been careful to model the overall handling of U-boats as best as they can, and seem to have done very well indeed in that regard.

If you like, and if I have the time and energy, I could pose this question to a bunch of people who know this kind of stuff.

[lafeeverted]

There should be a tighter turn at lower speeds, not necessarily a faster turn. ? Flight sims tell you to slow down to make tighter turns as the forward speed/g force has a large impact on manouverablilty, the same should hold true for the sub. But then again, we are not dealing with radical changes in speed 10 knots to 5 knots, here is where the inertia will come into play.

[caspofungin]

from what little i understand about things nautical, the difference is turn "rate" -- at higher speeds, the rate of turn (degrees per second is faster) but the distance covered during that second is also greater. so if you're turning at flank, although you get to your desired heading sooner, you've covered a lot more ground.

irl, if a destroyer was making a flank speed dc run on a sub, and that sub turned aside at the last moment, the destroyer, although it has a faster turn rate, would overshoot because it's going faster. the ship physics isn't so great in this game, what with the instant acceleration/deceleration, so you don't see that effect in game.

[Sailor Steve]

Caspofungin's explanation is pretty much on the money. During her turning trials on October 6, 1906, HMS Dreadnought at 21 knots took 40 seconds to turn through 45 degrees and 61 seconds to turn through 90 degrees, with a tactical diameter of 466 yards; but at 12 knots took 50 seconds to turn 45 degrees and and 85 seconds to turn 90 degrees, but the circle was tighter at 442 yards.

Usually faster speed should equal faster turns for a ship, just the opposite as with planes or cars. This is because a ship is much longer and thinner when compared with it's rudder size.

[Nedlam]

Would someone please be kind enough to explain to me the different speeds and when they should be used. ie Ahead one third (if thats not self explanatory), ahead flank etc.

As someone said earlier in this post ahead 1/3 usually is the best fuel economy decision.

Flank is use to, ummmmmm, out flank your target.

The other speeds I use to reach an itercept point using the speed that will get me there in enough time but at the same time not burn up too much fuel.

LOL, I forgot the name of the tool but I have something on my map that allows me to quickly calculate a pretty good estimate as to how fast I need to go to get to a certain point in a given time frame.

Then you have to factor in the weather, how much time your willing to remain on the surface (if your chasing your prey that way).

Hope that helps.

[_alphaBeta_]

You can easily tell the mot efficient speed by trying it out. I usually add a little time compression and manually order the speeds by specifying knots. I keep asking the navigator what the max range at this speed is.

For the Type VII and IX the efficiency point is 7 knots, and 9 knots with the engine upgrades. Not sure if that always equates to ahead 1/3. I don't think it does.