ship stopping distances

[Sailor Steve]

Originally Posted by jmardlin

They wouldn't be because reversing engines even at back emergency only uses about 2/3's ships power. So stopping distances should be slightly longer. But not by much because the screws are much more efficient running backwards because of less turbulence in the water.

Drag helps as well. Reversing the engines to stop the ship should make a big difference.

Here are the numbers I promised. The first is a graph made for a naval wargames study back in 1929. Kongo should be in the same area as Repulse.


This is an actual acceleration board from a WW2 aircraft carrier. Sorry I can't remember which one, but at the time I wasn't in a position to record where stuff I was downloading came from.

[gimpy117]

this would really change the game. ships can't just accelerate to avoid torpedoes as well anymore and V&W destroyers (or the Japanese equivalent) can't come screaming in at 35 knots to ram you after traveling with a convoy at 7 knots.

Originally Posted by gimpy117

this would really change the game. ships can't just accelerate to avoid torpedoes as well anymore and V&W destroyers (or the Japanese equivalent) can't come screaming in at 35 knots to ram you after traveling with a convoy at 7 knots.

well there is a hard coded issue where all ships get a free jump to 0-5 kts in 10-15 seconds and from 5 kts up you can actually control what they do, so they still can move out of the way on you but a bow shot should clip them in the rudders unless your too far away. but this is still better than stock where they go 0-5 kts in 2 or 3 seconds.

[JREX53]

Originally Posted by WEBSTER

well there is a hard coded issue where all ships get a free jump to 0-5 kts in 10-15 seconds and from 5 kts up you can actually control what they do, so they still can move out of the way on you but a bow shot should clip them in the rudders unless your too far away. but this is still better than stock where they go 0-5 kts in 2 or 3 seconds.

Webster,

That isn't exactly accurate. I have been able to get merchant ships to only make 5 to 6 knots in the 1st minute, and to get them so that they don't reach their top speed for up to 20 minutes by just changing the engine HP and engine RPM.

As a suggestion, I would not use just the drag coefficients to cause the speed changes. You lead yourself open for weird things to happen in game.

Originally Posted by JREX53

Webster,

That isn't exactly accurate. I have been able to get merchant ships to only make 5 to 6 knots in the 1st minute, and to get them so that they don't reach their top speed for up to 20 minutes by just changing the engine HP and engine RPM.

As a suggestion, I would not use just the drag coefficients to cause the speed changes. You lead yourself open for weird things to happen in game.

i havent messed with rpms yet...

[JREX53]

Webster,

That is what I am getting at. You have changed the drag coefficients unnecessarily.
The advice I was given by Sam (swdw), who started the initial physics work for SH4, gave me was to adjust the engine HP until you get into the ballpark, then adjust the engine rpm to get what you want, otherwise if you just change the drag coefficients you are asking for the ship to do weird things ingame.

He also said that because of the game engine was to try to set your timings with about 3 or 4 knots below top speed. The game engine actually slows down the rate of acceleration so that the ship doesn't overshoot its max speed.

Another point of interest is trying to get the ships to use reverse engine speeds you almost have to box the ship in so that it cannot turn. I have tried to get it to use reverse speeds by putting a ship in its path, but it will turn to avoid the ship instead of using reversing speeds.

[vanjast]

Originally Posted by JREX53

Webster,
Another point of interest is trying to get the ships to use reverse engine speeds you almost have to box the ship in so that it cannot turn. I have tried to get it to use reverse speeds by putting a ship in its path, but it will turn to avoid the ship instead of using reversing speeds.

I've noticed shooting a torpedo at the ship causes it to 'put on the brakes'. If you fire all torps at 5 sec intervals in front of the ship it might work.

Originally Posted by JREX53

Webster,

That is what I am getting at. You have changed the drag coefficients unnecessarily.
The advice I was given by Sam (swdw), who started the initial physics work for SH4, gave me was to adjust the engine HP until you get into the ballpark, then adjust the engine rpm to get what you want, otherwise if you just change the drag coefficients you are asking for the ship to do weird things ingame.
.

the drag coeficients were used from PT's advice and i threw those values i used away and settled on new values.

i worry lowering rpm too much will cause ships that slow for evasive zig zag manuvers to get stuck doing 5 kts trying to regain speed. do you have a suggested number to start at?