MTC Marine Plumbing & Sanitation Systems 2 — Questions and Answers
Question 1: What component is installed between the seacock and the raw water pump to protect the impeller from debris and marine growth?
- Raw water strainer (Correct answer)
- Anti-siphon valve
- Vented loop
- Pressure relief valve
Correct answer: Raw water strainer
A raw water strainer filters sediment, shells, and debris from incoming seawater before it reaches the impeller, preventing damage and blockage.
Question 2: At what interval should a raw water pump impeller typically be inspected or replaced on a marine engine?
- Every 25 hours or at each seasonal launch
- Every 100 hours or annually, whichever comes first (Correct answer)
- Every 500 hours or every 5 years
- Only when overheating symptoms are observed
Correct answer: Every 100 hours or annually, whichever comes first
Most manufacturers recommend inspecting or replacing the raw water impeller every 100 hours or annually to prevent unexpected cooling system failure.
Question 3: What is the primary function of a bilge pump aboard a marine vessel?
- To circulate raw cooling water through the engine
- To remove accumulated water from the lowest part of the hull (Correct answer)
- To pressurize the onboard freshwater system
- To transfer fuel between tanks when one runs low
Correct answer: To remove accumulated water from the lowest part of the hull
The bilge pump removes water that collects in the bilge—the lowest interior part of the hull—to keep the vessel safe, dry, and buoyant.
Question 4: Which type of bilge pump system is designed to activate automatically without crew intervention when water reaches a preset level?
- Manual diaphragm pump operated by a handle
- Electric centrifugal pump with an automatic float switch (Correct answer)
- Hand-operated piston pump mounted at the helm
- Submersible gear pump controlled by a timer
Correct answer: Electric centrifugal pump with an automatic float switch
An electric centrifugal bilge pump with a float switch automatically activates when rising water lifts the float, providing protection even when no one is aboard.
Question 5: What is the correct winterizing procedure for a marine vessel's freshwater plumbing system to prevent freeze damage?
- Fill all lines with seawater which has a lower freezing point than fresh water
- Drain all water from lines and add non-toxic propylene glycol (RV) antifreeze (Correct answer)
- Add automotive ethylene glycol antifreeze to the freshwater tanks
- Leave water in the lines since modern marine hoses are freeze-resistant
Correct answer: Drain all water from lines and add non-toxic propylene glycol (RV) antifreeze
Draining all water and adding non-toxic RV antifreeze (propylene glycol) protects plumbing from freeze damage while remaining safe for potable water systems.
Question 6: What is a 'barb' fitting most commonly used for in marine plumbing applications?
- High-pressure hydraulic hose connections
- Connecting flexible hose to rigid pipe, pumps, or fixtures (Correct answer)
- Through-deck watertight electrical penetrations
- Rigid pipe-to-pipe threaded unions below the waterline
Correct answer: Connecting flexible hose to rigid pipe, pumps, or fixtures
Barb fittings have ridged projections that grip the inside of a flexible hose when secured with a clamp, creating a reliable and leak-resistant connection.
Question 7: What does 'positive flotation' mean in the context of a vessel's safety systems?
- The bilge pump creates positive water pressure to eject water overboard
- The vessel contains enough built-in buoyancy material to remain afloat even if the hull fills with water (Correct answer)
- The float switch maintains a positive electrical signal to the pump at all times
- The pump is rated to maintain positive pressure in the bilge discharge line
Correct answer: The vessel contains enough built-in buoyancy material to remain afloat even if the hull fills with water
Positive flotation means the vessel is constructed with sufficient buoyancy foam or material that it will remain afloat even when completely swamped, independent of pumping.
MTC Marine Plumbing & Sanitation Systems 2
What component is installed between the seacock and the raw water pump to protect the impeller from debris and marine growth?