A handy and simple tool to determine in a minimum time what is really needed as tug assistance, is the Bollard Pull Calculator which calculates in an approximate way the total required tug power for ships in various conditions of wind and current. This tool can be loaded as an app on the smart phone.
Required tug power and number of tugs needed in variable conditions of wind, current and waves isin most cases an assessment made by pilots based on their professional experience. However, assessments will raise questions by lawyers if something goes wrong. They will use tools to calculate what really is needed with respect to tug power and number of tugs. They have furthermore the advantage of time.
