DCA Lesson 3 Test Review Questions and answers 2026

What are the 4 draft marks? Briefly describe them.

1. Calculative: Used for displacement

2. Navigational: Used for operational nav draft

3. Limiting: Reserved buoyancy

4. Plimsoll: Allowable freeboard (How much you can load)

What reference do you refer to for all ship-specific instructions?

DC Book

What are the 4 conditions of satisfactory stability and buoyancy for vessels?

1. Limiting drafts are not exceed

2. No abnormal topside weights

3. Liquid Loading Instructions are followed

4. Proper degree of watertight integrity is maintained

What information can be provided from a draft diagram?

1. Displacement

2. LCF

3. MT1

4. TPI

5. KM

6. LCB

List the 5 things the stability curve provides.

1. Righting arm

2. Danger angle

3. Max righting arm

4. Angle of maximum righting arm

5. Initial stability

List some ship design characteristics

1. MP

2. LBP

3. LCF

4. FP

5. AP

6. Designed waterline

What three things do you look at for weight additions?

1. PR/PS

2. Draft

3. Trim

What is a ships floodable length?

The maximum portion of a vessel's length, centered at a given point, that can be flooded at a specific permeability without submerging the margin line.

A small 'GM' has ____ roll recovery.

Slow

A large 'GM' has ____ roll recovery.

Quicker

Gravity moves ____ from weight removals.

Away

Gravity moves ____ weight additions.

Towards

As buoyancy increases, metacentric height ____.

Decreases

A dry dock or running aground is considered a weight ____.

Removal

What ships are designed with trim by the stern?

1. Icebreakers

2. Smaller ships

Why are some ships designed with trim by the stern?

To increase plant efficiency

Define Free Surface Effect.

When a compartment is partly filled with fluid, the liquid can flow from side to side as the vessel rolls and pitches.

Define Free Communication Effect.

Sea water goes in and out of a compartment reducing overall stability

What are the 3 conditions for Free Communication Effect?

1. Open to the sea

2. Partially flooded

3. Compartment off centerline

What methods are used to reduce FSE?

1. Pocketing

2. Reducing surface permeability

3. Installing swash bulkheads

4. Closing sluice valves

5. Venting

Flooding Effect Diagram (Green)

Flooding of green spaces will improve stability, even though free surface exists.

Flooding Effect Diagram (Yellow)

Flooding of yellow spaces will improve stability if no free surface exists. If space is not 100% full stability will be impaired.

Flooding Effect Diagram (Pink)

Flooding of pink spaces will decrease stability because of added high weight, free surface effect, or both.

Flooding Effect Diagram (White)

Flooding of white spaces has no appreciable effect on stability.

Liquid Loading Diagram (Green)

Clean ballast

Liquid Loading Diagram (Blue)

Potable Water

Liquid Loading Diagram (Pink)

JP-5

What is "Bodily Sinkage"?

Loss of Reserve Buoyancy

What is "Capsizing"?

Loss of Transverse Stability

What is "Plunging"?

Loss of Longitudinal Stability

What is "Breaking Up"?

Loss of Ship's Girder

Mother Goose Beats Kids

M: Metacentric Height (Moves opposite of B)

G: Center of Gravity (G follows weight added or shifted. G moves opposite weight removed)

B: Buoyancy (Follows the water line)

K: Keel

What is critical draft?

When the metacentric height (GM) equals 0

True or False: G moves faster than M?

True

What is 'positive' stability?

GM is greater than 0

What is 'negative' stability?

GM is less than 0

What is 'neutral' stability?

GM is 0

What NSTM covers dry docking?

NSTM 997

When are docking arrangements agreed on?

At the pre-docking conference, or 5-6 months prior

What are soft caps, and how thick should they be?

1. Form the top of keel blocks and side blocks

2. 2 inch minimum, 6 inch maximum

During docking and undocking when does responsibility of ship transfer?

When the first part of the ship crosses the plane of the dry dock sill.

What are divers used for during docking?

Inspect ship blocks to make sure the ship is resting correctly

List 3 causes of negative stability.

1. Removal of weight low

2. Addition of weight high

3. FCE or FSE

What logs does DCA provide prior to dry docking?

1. Last 2 dry dock reports

2. A list of all outboard valves

What requirements must be met for a ship prior to entering dry dock regarding its tank levels, list, and trim?

1. Tanks must be either emptied or full

2. 0 degree list

3. Less than 1% trim

What log does DCA maintain while in dry dock and when should they be notified?

1. The weight shift log

2. When the weight being moved exceeds 500 lbs

Who submits the leakage report?

CO

Who recieves the leakage report?

Dry Dock Officer

When does the leakage report get submitted?

Before flooding or lowering of the dock

List 3 ways of correcting negative stability.

1. Add weight low

2. Remove weight high

3. Eliminate FCE or FSE

What is ballasting?

Process of filling Low Compartment with Seawater to:

1. Improve Stability

2. Control List/Trim

3. Increase or decrease draft

What hull board inspections occur before undocking?

1. All outboard valves

2. External hull fittings in proper conditions for waterborne operations

3. The dock itself for debris

What hull board inspections occur during docking?

1. Propeller position

2. Shores are properly in place

3. Any known damage

4. Condition of zinc anodes and CAPAC

What must be done to the ship's propellers, rudders, and projecting devices before entering dry dock?

1. Rudders are locked amidships

2. Projecting devices are kept in retractable position

3. Propellers are in docking position

Who is responsible for developing the docking plan, and what items are included in it?

A. Everyone who attends the pre-docking conference

B. All locations of all keel blocks and side blocks, Tugs and pilots required, Working parties, Time and date of docking

What are the actions to be accomplished if a leak is reported during flooding of the dry dock?

If not major, continue, if major, stop flooding

What spaces are manned during undocking?

All spaces that had work and all spaces below the waterline

What are the 4 ways a ship experiences Critical Stability?

1. The ship has a negative GM

2. The ships is listing to the danger angle (1/2 angle of max GZ)

3. Floodable length exceeded

4. Damage with bad weather.

What is progressive flooding?

Flooding from compartment to compartment