Among the various causes that lead to collisions between offshore supply vessels and installation stands out mechanical failures as the third from top with a percentage of 13% according to the Gulf of Mexico collision incidents database in the period 1996 - 2009. Mechanical failures are often the direct outcome of bad maintenance, bad operation or human errors. This paper studies the types of mechanical failures that occur on board offshore supply vessels and presents a consequence analysis of some sample incidents that took place in the Gulf of Mexico in the period 1996-2009 in order to come up with practical recommendations that would help to reduce incidents from taking place or mitigate their negative effects.