A mooring winch is designed to have a...

🔍 Key Concepts

• Brake holding power vs. drum diameter – as wire builds up in layers, the effective drum radius increases and the brake’s holding capacity changes. • Manufacturer’s design assumptions – mooring winch brakes are calibrated for a certain number of working layers, not a completely full drum. • Safe working load (SWL) on the outer working layer – class rules and good practice usually specify the rated pull on a particular layer, not on all layers.

💭 Think About

• Think about how the tension on the brake changes when the wire is on the first layer compared to when it is several layers out from the drum core. Does more layers increase or decrease effective brake holding power? • Consider how many layers a winch can realistically keep under proper control without excessive slip when holding a ship alongside in bad weather. • Ask yourself: when manufacturers state the rated brake holding load, do they usually refer to an almost empty drum or a drum with a modest, standard number of layers?

✅ Before You Answer

• Verify how brake torque relates to effective radius of the drum as wire builds up in layers. • Check typical class rules or manufacturer guidance on the ‘rated layer’ for mooring winches (e.g., is it the 1st, 2nd, or more?). • Ensure you distinguish between storage capacity of the drum (total wire it can hold) and the recommended working layers for full brake capacity.

A mooring winch is designed to have a specific number of layers of wire on the drum for optimum brake capacity. How many layers are recommended?

one layer on the drum

two layers on the drum

three layers on the drum

four layers on the drum

🔍 Key Concepts

💭 Think About

✅ Before You Answer