other than the obvious..... what makes marine RCA's any different than the normal ones..... usually they shouldnt get water on them, maybe wrap some heatshrink over the physical connection? Never heard of em before...
i would check academy i noticed they have some marine audio stuff or get some of that white grease used on electrical connections and coat them before you install then heat shrink and i think that would be over kill
my friend specializes in boat installs and he uses the regular stuff