Deck General · Free Surface Effect
To minimize free surface effect in a fuel tank, the BEST practice is to:
- AKeep the tank at exactly 50% full
- BKeep the tank either nearly full or nearly empty, and use fewer, smaller tanks
- CSubdivide the tank with a longitudinal centerline bulkhead
- DBoth B and C are effective methods✓ Correct
Explanation
FSC is reduced by (B) keeping tanks nearly full or empty to minimize free surface area, and (C) adding a centerline bulkhead which splits one wide tank into two narrow tanks. Because FSC varies with the cube of tank width, halving the width reduces FSC to 1/8 per half. Both methods are used in practice.
Authority: Stability & Trim (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
- Free Surface Effect
Free surface effect (FSE) is caused by:
- Free Surface Effect
The free surface correction (FSC) for a tank depends on:
- Free Surface Effect
A vessel has a calculated GM of 2.0 feet. The total free surface correction for all slack tanks is 0.8 feet. What is the effective GM?
- Free Surface Effect
Free surface effect is GREATEST when a tank is:
- Free Surface Effect
A vessel has two identical slack fuel tanks side by side. Installing a centerline watertight division in each tank (creating four narrower tanks) will reduce the total free surface effect by approximately:
- Stability Definitions
Displacement is best defined as: