SAMS Vessel Stability and Naval Architecture 3

Question 1

The free surface effect reduces vessel stability because:

Accepted Answer

Liquid in a partially filled tank shifts to the low side when the vessel heels, raising the effective center of gravity

Answer

The added liquid weight increases overall displacement beyond design limits

Answer

It creates turbulent flow around the hull that reduces hydrodynamic lift

Answer

Liquid overflows onto the deck and reduces freeboard

Question 2

The Plimsoll mark (load line) on a vessel indicates:

Accepted Answer

The maximum permissible loading depths for various seasonal and geographic zones

Answer

The vessel's registered gross tonnage and net tonnage

Answer

The vessel's maximum authorized speed at full load displacement

Answer

The draft at which the vessel was initially launched and inclined

Question 3

In a vessel's stability booklet, the 'light ship' condition is defined as:

Accepted Answer

The completed vessel with no cargo, fuel, ballast, fresh water, stores, crew, or passengers

Answer

The vessel with only crew and essential navigation equipment aboard

Answer

The vessel at minimum operational ballast with half fuel stores

Answer

The vessel configured with only permanently fixed equipment and no consumables

Question 4

In naval architecture, 'trim' refers to:

Accepted Answer

The difference between the forward draft and the after draft

Answer

The transverse (side-to-side) inclination of a vessel at rest

Answer

The reduction of superstructure weight to lower the center of gravity

Answer

The vessel's speed relative to the surrounding water mass

Question 5

IMO intact stability criteria for most vessels primarily require:

Accepted Answer

Sufficient area under the GZ curve across defined heel angle ranges to resist dynamic forces

Answer

Freeboard must exceed 15% of the vessel's molded beam at all times

Answer

Metacentric height (GM) must remain positive throughout all loading voyages

Answer

Maximum draft must never exceed the keel depth plus 10% safety margin

Question 6

When calculating stability, an increase in the vessel's KG (height of center of gravity above keel) will:

Accepted Answer

Reduce stability by decreasing GM, bringing G closer to or above M

Answer

Improve stability by raising the metacenter proportionally

Answer

Have no effect on initial stability if the vessel is not currently heeled

Answer

Increase the righting moment at all positive angles of heel

Question 7

A 'stiff' vessel in terms of stability is one that:

Accepted Answer

Has a large GM, rolls quickly with a short period, and can be uncomfortable or dangerous for cargo

Answer

Has a small GM, rolls slowly and gently, and is very comfortable at sea

Answer

Has very high freeboard and large reserve buoyancy above the waterline

Answer

Has heavy permanent ballast that prevents any rolling in moderate seas