The operational capability of the Luhu-class destroyers has been called into question by naval analysts. Ship visits in 1997 allowed US Naval officers to board and inspect Luhu Destroyer No. 112 "Harbin" and to take numerous photographs. Analysis of these photographs and reports by officers present strongly suggested that the Luhu destroyers were mainly intended as technology demonstration vessels rather than serious naval combatants. For example, the large amount of foreign-supplied equipment onboard was still labeled in the language of the country of origin; this was also the case with most of the onboard manuals and other documentation, calling into question the ability of the crew to operate efficiently under stressful circumstances when called upon to deal with equipment labeled in English, French, or Italian, as well as Chinese. Furthermore, the various European systems installed were not originally designed to operate together and as a result were not well integrated - a problem the Chinese could not overcome owing to their lack of familiarity with the underlying technology. The Chinese attempted to address these problems with the introduction of an improved Luhu design, the Luhai-class. This follow-on, essentially an enlarged Luhu, features some improved electronics from foreign suppliers as well as more advanced weapons. However, in some cases, the designers appear to have opted for less capable indigenous designs to ease the system integration issues suffered by the Luhu-class destroyers. The PLAN was reportedly unhappy with the design of the Luhai-class destroyers and production ceased after a single unit was completed.