What is workability and why is it crucial for your offshore operations?


Working offshore is never easy. Apart from the job that needs to be done, there are outside factors to take into account, too – unpredictable weather and high sea states, to name just two.

A good plan is therefore crucial. We know that so we developed Ampelmann Insights, a data-driven platform that gives a boost to Walk to Work (W2W) operations. It provides timely, reliable and accurate data to help clients make informed decisions, review performance and optimise their operations day by day.

In other words, it forecasts the workability of operations and allows clients to better plan their work offshore. In order to understand the real value of Insights, though, there are a few questions we need to answer first.

To begin with, what is workability?

Workability is the percentage of time a W2W operation can be successfully executed. More specifically the percentage of time in which people and/or cargo can be transferred with the use of a gangway system. As an example, a workability of 80% over a period of 24 hours means that a successful W2W operation can be performed in 19.2 hours of the total period of 24 hours.

Secondly, what is a workability forecast?

A workability forecast is a prediction that takes into account the most important operational characteristics and concludes if a W2W operation can be executed. Two types of workability forecasts can be distinguished: short-term and long-term.

A short-term workability forecast focuses on 3 to 7 days, with a constant interval of 3 hours. That is the case because the majority of weather stations globally provide forecasts per every three hours.

A long-term workability forecast, on the other hand, can be considered to be a forecast for a longer period of time, as the name suggests, like the forecast for a four-month project.

So how is Ampelmann able to forecast the workability of a W2W operation?

A W2W operation consists of a couple of characteristics that together determine the workability:

  • Weather characteristics, such as waves, wind, swell, current
  • Vessel characteristics, such as length, weight, DP system, RAO
  • Gangway characteristics, such as the capabilities of the gangway

Put all those together and we are able to forecast the workability of a W2W operation.

The core of the calculation behind the workability forecast consists of three elements in itself. The first element is the behaviour of a ship when operating at sea - also known as the RAO (Response Amplitude Operator). The second element is the weather wave forecast from weather stations and the third is the compensation behaviour of the Ampelmann gangway.

At Ampelmann, we have created an algorithm that calculates all possible scenarios regarding the compensation of the motions of the vessel. The result is a percentage which indicates the workability during a specific period.

This is the first of two articles on the topic. Tune in for part II to learn details around how our workability forecasting works.

In the meantime, we are curious to hear your view on our solution. Have any thoughts or questions? Use the contact details below to get in touch with us!


Remco Schipperen

Simulation Engineer remco.schipperen@ampelmann.nl LinkedIn