The PCA’s mechanical dipper dredger Rialto M. Christensen (RMC) was built in 1977 by the Japanese Hakodate Dock Company in the days when the Canal was still under US governance. Designed to replace several classic steam dipper dredgers, RMC is a diesel-electric, cable-operated vessel designed for what’s acknowledged to be some of the most difficult conditions to be found anywhere. Not only does she play a daily role in maintaining navigation channels, but even though the Canal celebrated its 90th year in 2004, there’re still several places where its banks have yet to reach their so-called ‘angle of repose.’ And from time to time landslides occur that create shoals consisting of a variety of material, including large, heavy rocks.