Deck General · Blocks & Purchases
What is the purpose of a snatch block compared to a standard single block?
- AIt has a higher safe working load than an equivalent standard block
- BIts side opens to allow a line to be inserted without threading the end✓ Correct
- CIt is designed specifically for wire rope, not fiber line
- DIt contains an internal ratchet to prevent the line from running back
Explanation
A snatch block has a hinged side plate (cheek) that swings open so a bight of line can be dropped in without reeving the end through. This is invaluable for changing the lead of a line quickly at sea. SWL is based on block construction, not the opening feature; snatch blocks are suitable for both fiber and wire.
Authority: Deck Seamanship (USCG deck topic)
Practice the full Deck General bank
Free spaced-repetition quizzing across 2190 USCG exam questions — it schedules your reviews so the ones you miss come back until they stick.
Related Deck General questions
- Blocks & Purchases
A gun tackle consists of two single blocks. What is the mechanical advantage (MA) when hauling on the hauling part?
- Blocks & Purchases
A luff tackle uses a double block at the upper (fixed) end and a single block at the lower (moving) end. What is its theoretical mechanical advantage?
- Blocks & Purchases
Friction in a block and tackle system reduces the actual mechanical advantage. When estimating working efficiency, a rule of thumb deducts approximately what percentage per sheave?
- Stability Definitions
Displacement is best defined as:
- Stability Definitions
Deadweight tonnage (DWT) is defined as:
- Stability Definitions
Lightship displacement includes: