The ships in SH3 tend to behave like 'rubber ducks' when bobbing on the sea, bouncing around too much, and turning, accelerating and deaccelerating far too quickly. Philip Thomsen discovered in 2008 that alteration of four key parameters (eng_power, drag (of rudder), gc_height and 'LR'), found in the .sim file of each ship, could make this behaviour much more life-like. He published his findings at SubSim in its own thread, and distributed a number of modified .sim files.
See Thomsen's thread:
http://www.subsim.com/radioroom/showthread.php?t=143775
Thomsen's findings were confirmed by others, including by H.sie who distributed some further modified files, but there was much debate about which values to use - indeed, no clear consensus ever emerged. Moreover, many other players of SH3 could not use the files distributed by Thomsen and H.sie, since they caused clashes with their own sim files.
Therefore, I have decided to make this THOMSEN PARAMETERS APP available for general use, since it can be used to modify ALL ships currently used by ANY user in their SH3 installation.
THOMSEN PARAMETERS APP is an executable file (.exe) that searches through your SH3 'Sea' folder looking for ship.sim files (eg 'NKC3.sim'). It then replaces optionally any or all of eng_power, rudder-drag, surfaced left-right drag coefficient ('LR') and gc_height (= centre of gravity) with values specified by the user.
Every .sim file in your sea folder will be examined and altered!
(The instructions run to 2 1/2 pages, enclosed with the mod. I have tested the mod with about 180 sim files in NYGM (using recommended settings), but the app should work with any super mod, or even stock SH3, and with any ships made by others. Specifically, it functions correctly with IABL's MFM mod. Tests made by manual examination of a random selection of sim files for ships, and by carrying out 10 war patrols in mid Atlantic against a variety of convoys, and in single missions.)
Download from here:
http://www.subsim.com/mods1/nygm/ThomsenParamApp.7z
Stiebler.