High power, high-speed vessels such as torpedo boats, and torpedo boat catchers were subject to considerable vibration. The problem had become increasingly important, as higher and higher speeds were demanded. In reply to these demands Alfred Yarrow had conducted a series of experiments over a period of several years with the aim of elucidating the cause of vibration in high-speed vessels and developing a method of reducing it. Using a vibrometer devised by a Mr. Nesbitt, Yarrow had found that the removal of the propeller had no effect on effect on hull vibration and had concluded that vibration was therefore solely due to unbalanced machinery. This confirmed Otto Schlick's earlier observations that excessive vibration occurred when engine vibration due to incomplete balancing synchronised with the natural vibration of the hull. Yarrow solved the problem of excessive vibration in reciprocating engines by balancing the engines with "bob weights" in addition to the usual rotary weights. See also: 'Balancing marine engines and the vibration of vessels.' Transactions of the Institution of Naval Architects, vol. 33, 1892, pp. 213-228.