Various factors can form operational limits for the use of a vessel in seaway. Often these are excessive ship motions or accelerations, which can make human work in certain situations impossible or unsafe. On special vessels such limits can be connected to operation of certain equipment. On an offshore vessel or a research ship a limiting factor can be e.g. water motion in a moon pool. Many of these factors or parameter values can be directly measured in model tests, or the number of occurrences of an undesired event over time (shipping of green water, slamming) can be counted in a model test campaign in a defined seaway. Typically in-house numerical simulations would precede the model tests to improve the efficiency of the model testing.
Operability limits can also be of more functional nature, e.g. holding a vessel steady against an offshore windmill foundation, or launching and recovering a dinghy safely onboard in seaway. Many issues related to dynamic stability of the vessel in waves, e.g. steerability of high speed marine vehicle in waves or the dynamic stability of a vessel against excessive heeling in extreme sea states. The progress and level of success of the operation as a whole can be video recorded and evaluated.
- ship motions and accelerations
- shipping of green water
- slamming impacts
- steerability in waves
- DP -capability