MTC MTC Hull & Structural Systems 1 — Questions and Answers
Question 1: What is the primary purpose of a sacrificial anode on a marine vessel?
- To improve fuel efficiency
- To prevent galvanic corrosion on metal components (Correct answer)
- To reduce hull drag
- To stabilize the vessel in rough water
Correct answer: To prevent galvanic corrosion on metal components
Sacrificial anodes are made of a more active metal (zinc, aluminum, or magnesium) that corrodes preferentially to protect the hull and drive components from galvanic corrosion.
Question 2: When repairing a fiberglass hull blister, what is the FIRST step a technician should take?
- Apply gelcoat immediately
- Grind out the blister and allow the area to dry completely (Correct answer)
- Fill the blister with epoxy without opening it
- Sand the surface and apply antifouling paint
Correct answer: Grind out the blister and allow the area to dry completely
The blister must be opened, cleaned, and thoroughly dried before any repair material is applied to ensure a proper bond and prevent re-blistering.
Question 3: What material is most commonly used for repairing stress cracks in a fiberglass boat hull?
- Polyester resin only
- Epoxy resin (Correct answer)
- Marine silicone sealant
- Underwater epoxy putty alone
Correct answer: Epoxy resin
Epoxy resin provides superior adhesion and flexibility compared to polyester, making it the preferred choice for structural fiberglass hull repairs.
Question 4: What is the correct term for the measurement of a boat's displacement at rest in the water?
- Draft (Correct answer)
- Beam
- Freeboard
- Waterline length
Correct answer: Draft
Draft refers to the vertical distance between the waterline and the lowest point of the hull, indicating how deep the vessel sits in the water.
Question 5: Which type of bilge pump is most reliable for automatic operation in an unattended vessel?
- Manual diaphragm pump
- Electric submersible pump with float switch (Correct answer)
- Hand-operated piston pump
- Centrifugal belt-driven pump
Correct answer: Electric submersible pump with float switch
An electric submersible bilge pump with a float switch automatically activates when bilge water reaches a preset level, providing hands-free water removal.
Question 6: When inspecting a vessel's through-hull fittings, what is the primary concern a marine technician should address?
- Paint color consistency
- Corrosion, cracks, and proper seacock operation (Correct answer)
- Thread count of the fasteners
- Distance between fittings
Correct answer: Corrosion, cracks, and proper seacock operation
Through-hull fittings are critical points of failure; technicians must check for corrosion, cracks, and verify the seacock opens and closes freely to prevent sinking.
MTC MTC Hull & Structural Systems 1
What is the primary purpose of a sacrificial anode on a marine vessel?