SAMS Hull Inspection and Materials 4

Question 1

During a haulout survey of a fiberglass vessel, what is the significance of finding osmotic blisters primarily below the static waterline but not above it?

Accepted Answer

Confirms moisture permeation requires prolonged water immersion, consistent with osmosis

Answer

Osmotic blisters occur below the waterline because sustained water contact is required for moisture to permeate and initiate the hydrolysis reaction in the laminate.

Question 2

What is the primary purpose of a keelson in wooden hull construction?

Accepted Answer

To reinforce the keel from inside the hull and distribute loads

Answer

The keelson is an internal longitudinal timber bolted over the frames and keel, reinforcing the keel from inside and distributing structural loads along the hull's backbone.

Question 3

When a surveyor measures hull plate thickness on a steel vessel and finds wastage exceeding what percentage of original thickness, is replacement typically recommended?

Accepted Answer

20%

Answer

Generally, steel hull plating with wastage exceeding 20% of original thickness is considered to require repair or replacement to maintain structural integrity.

Question 4

Which condition is most indicative of 'hard spots' in a fiberglass hull?

Accepted Answer

Localized cracking in the hull skin aligned with underlying bulkhead or frame positions

Answer

Hard spots occur when hull skin cracks appear in lines that mirror the position of stiff internal members (frames, bulkheads) transferring point loads into the flexible laminate.

Question 5

In composite construction, what does the term 'print-through' refer to?

Accepted Answer

Telegraph of the woven fabric pattern visible through the gel coat surface

Answer

Print-through is the telegraphing of the weave pattern of underlying reinforcing fabric through the gel coat, caused by differential cure shrinkage.

(SAMS) Society of Accredited Marine Surveyors Certified Practice Test

(SAMS) Society of Accredited Marine Surveyors Certified Practice Test

SAMS Hull Inspection and Materials 4