Page 66 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

54 The Vehicle
Do not over design the system. The old saying goes that a chain is only as strong as its weakest link. Accordingly, all components of an ROV system should be rated to the maximum operating depth of the underwater environment anticipated, including safety factors. However, they should not be overdesigned. As the operating depth proceeds into deeper water, larger component wall thicknesses will be required for the air-filled spaces (pressure-resistant housings) on the vehicle. This increased wall thickness results in an increased vehicle weight, which requires a larger floata- tion system to counter the additional weight. This causes an increase in drag due to a larger cross section, which requires more power. More power drives the cable to become larger, which increases drag, etc. It quickly becomes a vicious design spiral.
Careful consideration should be given during the design phase of any ROV system to avoid overengineering the vehicle. By saving weight and cost during the design process, the user will receive an ROV that has the capability of providing a cost-effective operation. This is easier said than done, as “bells and whistles” are often added during the process or the “latest and greatest” components are chosen without regard to the impact on the overall system. Keep these ideas in mind as the various component choices are presented in the following chapters.