Types of Ships

In SimWAPS, a ship is modeled according to three input parameters. 

• Type : Determines overall proportions and structural characteristics, 
• Length : Directly influences dimensions and hydrodynamics performance, 
  
• Operational Speed : Used to compute apparent wind components and estimate vessel resistance.

These parameters enable us to establish a simplified but realistic model of performance under sails. 

Ship Types

SimWAPS takes into account different ship types. The underlying model remains the same for each type, only the proportions of the ship changes. Here are the main categories : 

• Container Ship : long and narrow, optimized for speed and the transport of containers stacked on the deck. 
  
• Bulker : Wide and deep, designed to transport bulk goods at moderate speeds. 
  
• Tanker : Rounded shape and increased stability, dedicated to transporting liquids at relatively low speeds. 

If you know the exact dimensions of your ship and don't want to use our geometric models, a custom ship type is also available. Here you can enter all the geometrical characteristics of your ship. 

Geometry estimation 

Depending on type and length, SimWAPS estimates : 

• Draft 
• Beam width
• Deck height 

Our models are based on data collected by MAN and centralized in the following three reports : 

• MAN Energy Solutions. (2022). Propulsion trends in bulk carriers. MAN Energy Solutions.
• MAN Energy Solutions. (2019). Propulsion trends in container vessels. MAN Energy Solutions.
• MAN Energy Solutions. (2021). Propulsion trends in tankers. MAN Energy Solutions.

Resistance and Energy Savings

Sails generate a propulsive force that reduce the engine power required to maintain speed, but also a lateral force, taken up by the hull and appendages, which prevents drift but introduces additionnal resistance. 

This lateral resistance slows the ship down and must be taken into account to correctly assess energy gains.

In addition to this, the model applies a simplified version of Holtrop-Mennen calculation to estimate relative power savings.