Just today sunk a light cruiser playing with TMO and RSRD mods only. It was not dark and the sea was not too rough. No rain and minimal fog.

I detected it on radar heading on a near parallel course same direction. Went to flank speed on the surface staying just on the edge of radar range until I reached a point of convergence of paths and sank to 150 rigged for silent running.

Waited it out for the cruiser to appear then come near to my firing position, rose to telescope depth and took a quick look at it (which was the first moment I saw it was a light cruiser), dropped the scope and set up 4 torpedoes, waited a little more then raised scope, fired my fish and dove to run if my attack failed.

One light cruiser less for the Japanese navy.

Since first post, i get used to TMO warships, and had some success sinking few of them.
But it remains they are very efficient and hard to close. This is the fun of it after all! :D

TMO was originially designed with challenge in mind. The idea was to amp up the game so as to create the sense of danger and trepidation that a real sub skipper most likely experienced when dealing with the enemy. Because the stock AI was so laughably bad (but not the legendary degree of FaIL of the stock SH5 AI:haha:) that, because of the aforementioned hard coding, the only way to achieve this was to uber the enemy units. TMO is meant to be challenging for its own sake. Conversely, RFB was designed to be as historically accurate as feasible with the game and, despite its own AI mods, appears comparatively easier, especially considering that sufficient familiarity with the Pacific war will give a player a distinct a priori advantage.

If one does not like TMO, either mod it to your taste or try one of the other megamods. There are more than enough choices to suit any player.