I don't think the submarine would fit into a "combat" group the expense is about the same though.
At least Hunt down a local scale model club in your area, Sub Committee or RC groups ought to be able to assist you in the search.
Oh, and RC boats are not that expensive...
RG is keeping a running tab...
Cost - Total to date: - $161.60
http://www.rcgroups.com/forums/showthread.php?t=371569