"Effect of Drift Force and unstable moment"
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SAMMON - the IDEAL tool to identify manoeuvring capabilities of a ship - SAMMON - learning the EFFECTIVE way
How to get information for wind & current limits to be potentially encountered by thrusters – or current? - this will be described in this movie:
- Measure Drift speed, due to beam wind with no propulsion;
- Measure drift speed using full thrusters
- Estimate wind & current limits to be potentially encountered by thrusters – or current...
- Finally there is a simple formula as Rule of Thumb: the transverse drift speed is about 7-8% of wind speed!
Another very good explanatory video by Knud Benedict. Absolutely worth seeing.
Yaw Stability is an important element of Ships Manoeuvrability - both for course keeping and turning ability. This first video in a series explains the Basic Principles of stability in steady state equilibrium conditions and the forces / moments involved
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.