The uboat game is not supported by TM. Some adjustments made to enhance the pacific game, will negativly effect the uboat game. About the only extent of support im able to offer for the uboat game, is to make sure it doesnt crash and functions as it should, "out of the box". Posted a fix here awhile ago.
http://www.ducimus.net/sh4/release/TMO_Enable_Uboat.7z