Why can I not designate tragets in LWAMI unless they are extremely close?

[FPSchazly]

Unfortunately it's just a side effect of LwAmi. Here's an excerpt from the manual, which I highly suggest you read, it's full of awesome info of how the game works at a program level. You can find it in the "Manual" folder of your Dangerous Waters game directory (assuming LwAmi is active of course).

Originally Posted by LwAmi 3.11 Manual

LWAMI increases the sensitivity of the Spherical/Cylindrical and Hull/Conformal arrays relative to towed arrays. This makes these arrays much more useful than before and conforms better to real-world performance. The change is seen most at the Broadband station—range is increased significantly, and some contacts may appear on Broadband sphere before Narrowband sphere. Note that some faint Broadband contacts may not be markable until they get a little bit closer (this issue is present in stock DW, but because of the increased sensitivity, it is encountered more frequently with LWAMI).