Deck General · Stability Definitions
Free communication with the sea — a hull breach allowing seawater to freely flood a space — primarily affects stability by:
- AIncreasing displacement and raising the waterline, which always improves GM
- BEffectively adding a large free surface that reduces GM, plus adding flood weight that raises G✓ Correct
- COnly affecting trim, not transverse stability
- DIncreasing reserve buoyancy in the flooded space
Explanation
Free communication with the sea means a flooded space now has a free surface as large as the opening — typically a major fraction of the waterplane. This creates a massive FSC reducing GM. Additionally, the added flood water weight raises G. Both effects degrade stability, potentially leading to capsize.
Authority: Stability & Trim (USCG deck topic)
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