Exam Question
Q5
Describe the relationship between frictional resistance and
(a) Ship speed
(b) The wetted surface area
(c) The surface roughness
(d) The length of the vessel.
Class 2 (2nd Engineer)
SC&S
📅 Mar 2026
Reference Answer
### Introduction to Frictional Resistance
Frictional resistance, denoted as $$ R_f $$, is a component of the total resistance experienced by a ship moving through water. It arises from the shear forces created by the viscosity of the water acting on the wetted surface of the hull. It is the dominant component of resistance at low to moderate speeds. The general formula for calculating frictional resistance is given by Froude's law of comparison:
$$ R_f = C_f \times \frac{1}{2} \rho S V^2 $$
Where:
Frictional resistance, denoted as $$ R_f $$, is a component of the total resistance experienced by a ship moving through water. It arises from the shear forces created by the viscosity of the water acting on the wetted surface of the hull. It is the dominant component of resistance at low to moderate speeds. The general formula for calculating frictional resistance is given by Froude's law of comparison:
$$ R_f = C_f \times \frac{1}{2} \rho S V^2 $$
Where:
Full answer on MeoMock — surveyor-grade reference answers for 7,000+ written exam questions.
Prepare on Android — MeoMock on Google Play