Here it is:
http://www.mediafire.com/?3qzxyk71fkjbhe6
It is based on IRAI for compatibility with TDW's mods. Changes done:
guns_radars_01.zon:
-added a SH3ZonesCtrl to reflector_base object, with a box set as WeaponsLight and a collision sphere centered on the reflector (though I am not sure that the latter is actually needed).
This is the core part of the mod.
guns_radars_01.sim:
-changed searchlight's beam color from full white to violet to reflect the spectrum of carbon arc lamps that WWII reflectors were based on;
-changed serchlight range from 200 mt to half a mile (the stock figure seemed a bit too short to me);
-adjusted attenuation parameters to reflect the new range.
Those changes are a bonus by me. You can remove the sim file from the mod if you don't like my settings, or you can give me your suggestions for improving them.
The mod comes with an historical mission based as well on TDW's torpedo tutorial mission. Just surface, get closer to the merchant and start fire for making her to turn on her searchlights. I was able to switch off one of them the hard way

, with one well aimed shot (at close range)
