ONE OF ROCK'S cardinal virtues is its ability to turn limitations into strengths.

One of the keys to rock, after all, is a simple intensity that demands not competence so much as the willingness to push one's ability to the edge. Which is why the Diversions, a local three-piece group long on instrumental talent but short on vocal ability, manage to come out ahead on "Here It Is," their self- produced debut.

It isn't as if the trio wouldn't benefit from better singing, because such songs as "Hearts Like That" and "Painting Myself Into a Corner" boast sufficient melodic potential that the listener can't help but wonder what might have been added by a more competent vocalist. But the fact that the group's members have adjusted their music so that it puts across, if not all the notes, then at least all their personality, helps ake this album an enjoyable mishmash of musical styles.

Because rock isn't terribly long on instrumental sub-genres, the Diversions are left with two basic alternatives: surf numbers such as "Surfin' Pharaohs" and "Sky Dive," and ska numbers such as "The Saint." Guitarist Brian Damage has no difficulty delivering the strict articulation and whammy-bar-assisted tremolo that surf music demands, but bassist Lee Ska too often wavers between carrying a secondary melodic line and providing a solid bottom.

In the end, though the Diversions demonstrate admirable ingenuity in dealing with both their material and their talent, they still have some way to go before realizing their potential. Here's hoping they keep us posted on their development.

THE DIVERSIONS -- "Here It Is" (D.M. Records D.I. 1002); appearing Saturday at Friendship Station.