The present Gilbert and Sullivan offering by the Washington Savoyards is a marathon event. With "Trial by Jury" as warm-up, "H.M.S. Pinafore" follows. One has to like Gilbert and Sullivan a lot.

Even with the lively enthusiasm of the cast and the ebullient professionalism of Christian Mendenhall as both the Learned Judge in "Trial" and Sir Joseph Porter in "Pinafore," the full presentation lacks theatrical excitement. Musically and directorially, the unvaried pacing ignores the dramatic tide that carries any stage piece along. The plots are creaky and too familiar, but they work; Gilbert and Sullivan knew their business. But in more than three hours, variety was hard to find amid the inflexible tempos with stage movement to match. The big numbers seldom came off, save when Mendenhall was at work.

The singers were not wholly to blame for not always delivering the words. The speed of language or music depends on the speed with which it is heard, not on fixed miles per hour. Slightly slower can sound faster if everything is heard. When tenor Hugh Harvey III, playing Rackstraw in "Pinafore," demanded room for breath and drama, he got it, thereby improving his performance and showing his lyric qualities to advantage.

Staging problems were caused by sets too representational for the space. Freestyle sets would have given room for the actors to move. In "Trial by Jury" it was almost impossible to cross the stage; in "Pinafore" actors had to line up to enter and exit, which did little for the flow of action.

Odd casting choices caused odd results: Buttercup sings of "many years ago" but is not old enough to be credible; Cousin Hebe should be somewhat long in the tooth, not, as her portrayer was, a very pretty girl.

But, in spite of all temptation to criticize, it remains likable, the music continues to surprise, and the effervescence is inherent. That's why Gilbert and Sullivan continue, and why we continue to go to their operettas.

Performances continue through Sunday at Trinity Theatre.