Added Resistance Head Seas - STAwave-1

Introduction

STAwave-1 is developed by STA-JIP to estimate the added resistance when sailing in a given sea state. The main benefit to the method is that it only requires the breadth of the ship and length of the bow on the waterline to 95% of the maximum breadth.

The method is only usable in low to mild sea states and head seas as it assumes negligible wave induced motion. The reason for this is that only added resistance generated by the wave reflected of the hull at the waterline is accounted for. The added resistance is independent of the ship speed.

Definiton of LBWL
Definition of LBWL

Limitations

  • Significant wave height \(H_s \leq 2.25\sqrt{L_{pp}/100}\)
  • Heave and pitch small i.e. vertical acceleration at bow less than 0.05g
  • Head waves

Calculator

Description Symbol Value Unit
Significant wave height Hs m
Length of the bow on the water line to 95% of maximum breadth LBWL m
Breadth B m
Density ρ t/m3