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newSchoolWorks.com › VoTechWorks › Manufacturing & Marine › Shipbuilding / Marine Fabrication › Certification Exam Preparation: Shipfitting, Maritime Welding, AWS & ABS/USCG Credentials › Lesson 2
MFG-SHIP13-09 · Lesson 2 · 28 clock hours · theory

NCCER Knowledge Domain Review: Shipfitting & Maritime Welding

Objective. Learners will answer practice questions drawn from every NCCER Shipfitting and Maritime Welding knowledge domain at or above the NCCER passing standard on two timed module-level practice tests.

Why a Domain-by-Domain Review Works

NCCER knowledge tests are organized by module, and each module maps to a specific knowledge domain—structural nomenclature, drawing interpretation, welding process selection, and so on. Passing any NCCER credential requires demonstrating competence across all domains, not just the ones that feel comfortable. A targeted, domain-by-domain review lets you find weak spots before the real exam, fix them with focused practice, and confirm improvement with a timed re-check.

The passing standard for NCCER written assessments is 70%. That means you must answer at least 42 of 60 questions correctly on each practice test in this lesson. Treat that number as a floor, not a goal.

Core Domain 1: Ship Structural Nomenclature and Hull Geometry

Every shipfitter must speak the language of the hull. Key terms include keel (the backbone of the vessel running fore to aft along the bottom centerline), frames (transverse members that shape the hull), longitudinals (fore-and-aft stiffeners), bulkheads (vertical transverse or longitudinal dividing walls), decks, gunwale, bilge, camber (the athwartship crown of a deck), and sheer (the longitudinal curve of the deck edge). Hull geometry is described using the baseline, centerline, stations (equally spaced cross-sections), waterlines, and buttock lines. These three sets of parallel cutting planes form the lines drawing—the foundation of all lofting and template work.

Core Domain 2: Reading Marine Construction Drawings, Weld Maps, and Bills of Materials

Marine drawings follow standards similar to ASME Y14.5 for dimensioning and AWS A2.4 for welding symbols. A weld map overlays welding symbols on the structural drawing and identifies each joint by type, process, and inspection requirement. A bill of materials (BOM) lists every plate, section, fitting, and fastener with its material specification, dimensions, and quantity. When reading a BOM, cross-reference the material specification (for example, ABS Grade A or ASTM A36) against the drawing note to confirm the correct grade is called out before cutting.

Welding symbols on marine drawings follow AWS A2.4. The reference line, arrow, tail, and weld symbol work together to specify weld type (fillet, groove, plug), dimensions, finish, and any testing requirements. Misreading a welding symbol—especially the arrow-side versus other-side designation—is a common source of errors in both the exam and on the job.

Core Domain 3: Template and Pattern Development

Templates transfer the geometry of the lines drawing to actual material. Shipfitters use spiling to fit curved members to an irregular surface and mold loft geometry to develop flat patterns for curved shell plates. On the practice test, expect questions about which reference plane a template is lifted from and how to account for material thickness (known as setback or margin) when laying out a template.

Core Domain 4: Fastener and Fitting Identification

Shipyard fastenings include structural bolts to ASTM specifications, temporary dogs and strong-backs for alignment, and various pipe and penetration fittings. Know the difference between a fairlead, a chock, a cleat, and a bit—they each have distinct structural requirements and load directions.

Core Domain 5: Welding Process Selection and Procedure Variables

The four processes covered by NCCER Maritime Welding are SMAW (Shielded Metal Arc Welding), FCAW (Flux-Cored Arc Welding), GMAW (Gas Metal Arc Welding), and GTAW (Gas Tungsten Arc Welding). Marine structural work most commonly uses SMAW and FCAW because both tolerate field conditions. GTAW is standard for aluminum pipe and thin sections. Key procedure variables include amperage, voltage, travel speed, electrode/wire classification, polarity, preheat, and interpass temperature. Changing any of these beyond the range listed in the Welding Procedure Specification (WPS) without re-qualification is a code violation.

Heat input is calculated as: Heat Input (kJ/in) = (Amps × Volts × 60) ÷ (Travel Speed in/min × 1000). Controlling heat input directly controls distortion and the heat-affected zone (HAZ). High heat input risks warping thin shell plating and reducing toughness in the HAZ.

Core Domain 6: Distortion Control and Heat Input Management

Common distortion control methods include presetting (pre-bending members opposite to expected distortion), backstep welding, skip welding, strongback and wedge restraint, and balanced welding on both sides of a neutral axis. Peening is sometimes permitted between passes but must be explicitly allowed by the WPS.

Core Domain 7: Marine Safety — OSHA 29 CFR 1915, Confined Space, and Hot Work

Shipyard safety is governed by OSHA 29 CFR Part 1915, not the general-industry 1910 or construction 1926 standards. Subpart B covers confined and enclosed spaces and other dangerous atmospheres. Before entering any confined space aboard a vessel, employers must test for oxygen content, flammable gases, and toxic contaminants. Subpart Q covers welding, cutting, and heating. Hot-work permits are required before any open-flame or arc-welding operation inside a vessel. Lockout/tagout (LOTO) procedures under 1915.89 must be followed whenever energy sources—electrical, hydraulic, pneumatic, or stored mechanical—are isolated for maintenance or repair. Always wear appropriate PPE: welding helmet with the correct lens shade, flame-resistant clothing, leather gloves, and hearing protection in high-noise zones.

Key terms10

Lines DrawingA set of three orthographic views—body plan, half-breadth plan, and sheer plan—that define the three-dimensional shape of a hull using equally spaced stations, waterlines, and buttock lines.
Weld MapA drawing or overlay that assigns welding symbols, processes, filler metal classifications, and inspection requirements to each joint in a structure, following AWS A2.4 symbol conventions.
Bill of Materials (BOM)A structured list identifying every component in an assembly by part number, material specification, dimensions, and quantity required; used for procurement and quality control.
Welding Procedure Specification (WPS)A qualified, written document that specifies the essential and non-essential variables—process, filler metal, preheat, heat input range, and more—that must be followed to produce an acceptable weld.
Heat InputThe amount of electrical energy delivered to a weld per unit length, calculated from amperage, voltage, and travel speed; used to control distortion and heat-affected zone toughness.
SpilingA template-fitting technique in which a batten or scribing tool transfers the exact curvature of an existing surface to a flat template so that a new member can be cut to fit precisely.
OSHA 29 CFR 1915The federal OSHA standard that regulates occupational safety and health specifically in shipyard employment, covering topics from confined spaces (Subpart B) to welding and cutting (Subpart Q).
Hot-Work PermitA formal written authorization required before any welding, cutting, or open-flame work aboard a vessel or in areas where flammable or combustible materials may be present, as required under OSHA 1915 Subpart Q.
CamberThe transverse, athwartship curvature built into a deck so that water drains to the sides; typically expressed as a rise per unit of beam.
Backstep WeldingA distortion-control technique in which short weld increments are deposited in the direction opposite to the overall progression of the weld, reducing cumulative heat buildup in any one area.

Worked examples4

1. Calculate the heat input for a FCAW pass made at 220 A, 26 V, and a travel speed of 11 in/min. Express the answer in kJ/in and state whether this is higher or lower than a pass made at the same amperage and voltage but at 14 in/min.
  1. Write the heat input formula: Heat Input (kJ/in) = (Amps × Volts × 60) ÷ (Travel Speed in/min × 1000).
  2. Substitute the first set of values: (220 × 26 × 60) ÷ (11 × 1000) = 343,200 ÷ 11,000.
  3. Calculate: 343,200 ÷ 11,000 = 31.2 kJ/in (rounded to one decimal place).
  4. For the comparison pass at 14 in/min: (220 × 26 × 60) ÷ (14 × 1000) = 343,200 ÷ 14,000 = 24.5 kJ/in.
  5. Compare: 31.2 kJ/in > 24.5 kJ/in, so the slower travel speed produces higher heat input.
Answer: Heat input at 11 in/min = 31.2 kJ/in; at 14 in/min = 24.5 kJ/in. The slower pass delivers higher heat input, increasing distortion risk and potentially widening the heat-affected zone.
2. A weld map calls for a 3/8-inch fillet weld on the arrow side of a T-joint between a longitudinal stiffener and the shell plate. The symbol shows an 'F' in the tail. What does the tail notation indicate, and which surface receives the weld?
  1. Identify the components of the AWS A2.4 welding symbol: the reference line, arrow pointing to the joint, the weld symbol (fillet triangle) below the reference line for arrow side, the size '3/8' to the left of the symbol, and the tail.
  2. The weld symbol below the reference line means the weld is on the arrow side—the side the arrow physically points to on the joint.
  3. The tail of the welding symbol is used to designate the welding specification, process, or other reference. An 'F' in the tail typically references a specific filler metal or finish designation per the project's standard; confirm by checking the drawing legend.
  4. Conclusion: the 3/8-inch fillet weld is deposited on the arrow side of the T-joint; the tail notation 'F' directs the welder to a reference document or finish requirement listed in the drawing's symbol legend.
Answer: The weld is placed on the arrow side of the T-joint (the side to which the arrow points). The 'F' in the tail refers to a finish or reference designation defined in the project drawing legend—always check the legend before welding.
3. A shell plate layout requires a setback of 1/2 inch from the theoretical mold line to allow for the plate thickness of 1/2 inch. If the mold-line length of an edge is 48 inches, what is the cut length of the plate edge after applying the setback on one end only?
  1. The mold line represents the outside of the finished structure. The plate is cut so its outside face aligns with the mold line.
  2. A setback on one end shortens the template measurement by the plate thickness (1/2 inch) on that end only.
  3. Cut length = mold-line length − setback on one end = 48.0 in − 0.5 in = 47.5 in.
Answer: The cut length of the plate edge is 47.5 inches.
4. An oxygen reading inside a void space measures 19.0% by volume. Can workers enter without supplied-air respiratory protection under OSHA 1915 Subpart B?
  1. OSHA 1915 Subpart B defines an oxygen-deficient atmosphere as one containing less than 19.5% oxygen by volume.
  2. 19.0% is below 19.5%, so the space is classified as oxygen-deficient.
  3. Entry without supplied-air (or SCBA) respiratory protection is prohibited; the space must be ventilated and re-tested until oxygen content is at or above 19.5% before workers may enter without respiratory protection.
Answer: No. At 19.0% oxygen the space is oxygen-deficient under OSHA 1915 Subpart B. Workers may not enter without supplied-air respiratory protection, and ventilation plus re-testing must occur before unprotected entry is allowed.

The math in this lesson1

Learners compute FCAW heat input in kJ/in from 220 A, 26 V and 11 in/min.
A-SSE.1
Brush up in the math halls at newSchoolWorks.com:
In class: Rotating small-group stations (90 minutes each over multiple sessions) covering the core NCCER knowledge domains: ship structural nomenclature and hull geometry; reading marine construction drawings, weld maps, and bill of materials; template and pattern development; fastener and fitting identification; welding process selection (SMAW, FCAW, GMAW, GTAW) and procedure variables for marine applications; distortion control and heat input management; marine safety regulations including confined-space entry, hot-work permits, and shipyard-specific OSHA 1915 subpart requirements. Each station uses flashcard drills, short whiteboard problems, and annotated drawing exercises. · Learners complete two timed, 60-question practice knowledge tests—one mapped to NCCER Shipfitting domains and one to NCCER Maritime Welding domains—under closed-book, exam-simulating conditions; after scoring, learners compare results to their gap-analysis plan and update study priorities. · Peer-teaching exercise: each learner selects one domain where they scored highest and teaches a 10-minute mini-lesson to a small group using a whiteboard and one sample practice question, reinforcing retention and exposing remaining misconceptions for instructor correction.
Materials: NCCER Shipfitting Trainee Guide, NCCER Maritime Welding Trainee Guide, printed NCCER-style practice test packets (school-developed from module review questions), marine construction drawing sets from the capstone project, welding symbol reference charts per AWS A2.4, whiteboard and markers, OSHA 29 CFR 1915 Subparts B and Q reference cards.
Check: Learner scores ≥70% on both the Shipfitting and Maritime Welding timed practice tests before advancing; learners below 70% on any domain receive a targeted re-teach from the instructor and must re-attempt that domain's 20-question mini-quiz to ≥70% before the course proceeds.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

NCCER Shipfitting – Ship Structural Nomenclature and Hull Geometry
1. On a hull lines drawing, which set of parallel cutting planes runs horizontally and parallel to the baseline to produce elliptical or curved intersections with the hull surface?
NCCER Shipfitting / Maritime Welding – Reading Marine Construction Drawings
2. According to AWS A2.4, when a fillet weld symbol appears ABOVE the reference line of a welding symbol, the weld is to be placed on the:
NCCER Shipfitting – Template and Pattern Development
3. A shipfitter needs to fit a curved longitudinal to the inside of a hull frame that has an irregular curve. Which technique is most appropriate for transferring the exact shape of the existing surface to a template?
NCCER Maritime Welding – Welding Process Selection and Procedure Variables
4. A welder is running FCAW at 230 A, 27 V, and 10 in/min travel speed. What is the heat input in kJ/in?
NCCER Maritime Welding – Welding Process Selection
5. Which welding process is most commonly selected for joining thin aluminum sections in marine construction because of its clean arc, precise heat control, and absence of flux residue?
NCCER Shipfitting / Maritime Welding – Marine Safety, OSHA 1915
6. Before a worker may enter a confined space aboard a vessel under OSHA 29 CFR 1915 Subpart B, the atmosphere must be tested for all of the following EXCEPT:
NCCER Maritime Welding – Welding Procedure Variables and Distortion Control
7. A WPS authorizes a preheat of 150°F minimum and an interpass temperature not to exceed 400°F. During production welding, an infrared thermometer shows the joint at 430°F before the next pass. What is the correct action?
NCCER Shipfitting / Maritime Welding – Marine Safety, Hot-Work Permits, OSHA 1915
8. A hot-work permit is required before arc welding inside a vessel compartment primarily to:
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