SAMS Hull and Machinery Surveyors 2 — Questions and Answers
Question 1: When inspecting a vessel's keel bolts, which condition most strongly indicates electrolytic corrosion rather than simple galvanic corrosion?
- Uniform pitting across all bolt surfaces
- Preferential wastage on bolts nearest the bilge pump discharge (Correct answer)
- Corrosion concentrated at the bolt-to-keel interface only
- Bright metal appearance with shallow cratering
Correct answer: Preferential wastage on bolts nearest the bilge pump discharge
Stray current electrolytic corrosion tends to concentrate near electrical discharge points such as bilge pump outlets, unlike galvanic corrosion which follows dissimilar metal contact zones.
Question 2: Under ABYC standards, what is the minimum thickness of fiberglass laminate generally required at the chainplate attachment area of a sailing vessel?
- Equal to the adjacent hull laminate
- Twice the adjacent hull laminate thickness
- Three times the adjacent hull laminate thickness
- No specific multiplier; engineer's calculation governs (Correct answer)
Correct answer: No specific multiplier; engineer's calculation governs
ABYC standards do not specify a fixed multiplier; chainplate backing must be engineered to distribute the load without failure, typically verified by calculation or load testing.
Question 3: A marine surveyor detects osmotic blistering on a GRP hull. Which test provides the most definitive quantification of moisture intrusion in the laminate?
- Visual blister count per square foot
- Pin-type moisture meter reading
- Hammer sounding for delamination
- Core sample gravimetric moisture content analysis (Correct answer)
Correct answer: Core sample gravimetric moisture content analysis
Gravimetric analysis of core samples measures actual water weight gain in the laminate, providing quantitative data that surface moisture meters cannot match in accuracy.
Question 4: Which structural element connects the deck to the hull shell and is critical for resisting racking forces in a monohull sailboat?
- Bilge stringer
- Deck beam
- Hull-to-deck joint (Correct answer)
- Floor timber
Correct answer: Hull-to-deck joint
The hull-to-deck joint transfers lateral racking loads between the topsides and deck structure, making its integrity essential to overall hull stiffness.
Question 5: When assessing a diesel engine's crankshaft deflection readings, what does an increasing deflection spread from forward to aft bearings typically indicate?
- Normal bearing wear within tolerance
- Engine foundation hogging or hull distortion (Correct answer)
- Crankshaft journal out-of-round
- Excessive lubricating oil viscosity
Correct answer: Engine foundation hogging or hull distortion
A progressive deflection trend along the crankshaft axis suggests the engine foundation or hull girder has distorted, causing misalignment between bearing saddles.
Question 6: During a haul-out survey, a surveyor observes that antifouling paint has worn through to bare gelcoat on the keel-to-hull fillet only. What is the primary concern?
- Increased hydrodynamic drag from fouling growth
- Crevice corrosion initiation in a high-stress laminate joint (Correct answer)
- UV degradation of the gelcoat surface
- Paint adhesion failure requiring full hull strip
Correct answer: Crevice corrosion initiation in a high-stress laminate joint
The keel-to-hull fillet is a high-stress area subject to flexing; bare substrate in this zone is vulnerable to crevice corrosion (on metal keels) or moisture ingress into a stressed laminate joint.
Question 7: Which SAMS guideline requires a marine surveyor to disclose a material relationship with a vessel being surveyed?
- SAMS Ethics Canon 3 — Conflict of Interest disclosure (Correct answer)
- SAMS Technical Bulletin 7 on survey methodology
- ABYC E-11 electrical standard
- 46 CFR Part 188 documentation rules
Correct answer: SAMS Ethics Canon 3 — Conflict of Interest disclosure
SAMS Ethics Canon 3 mandates that surveyors disclose any financial, personal, or professional relationship that could compromise impartiality when surveying a vessel.
SAMS Hull and Machinery Surveyors 2
When inspecting a vessel's keel bolts, which condition most strongly indicates electrolytic corrosion rather than simple galvanic corrosion?