PRC Naval Architecture & Marine Engineering cheat sheet
PRC Naval Architecture & Marine Engineering · Keep the key ideas within reach.
Naval Architecture
Displacement Δ = ρ·∇·C_B·L·B·T; block coefficient C_B = ∇/(L·B·T) uses the same length convention (LWL or LPP) consistently across all coefficients.
Froude number Fn = V/√(gL); a hull's wave-making resistance pattern is governed by Fn, so geometrically similar hulls at equal Fn have comparable wave resistance coefficients.
Reynolds number Rn = V·L/ν; frictional resistance coefficient uses the ITTC-1957 line C_F = 0.075/(log10 Rn − 2)².
Total resistance coefficient C_T = C_F + C_R + C_A + C_AA, where C_R is model-derived residuary resistance, C_A is hull roughness allowance, C_AA is air resistance.
Metacentric height GM = KB + BM − KG; BM = I/∇ where I is the waterplane second moment of area about the centreline. Positive GM indicates initial transverse stability.
Righting lever GZ = GM·sin φ for small angles; beyond about 10–15 degrees the full GZ curve from cross curves of stability must be used.
Free-floating trim and heel follow from moment equilibrium: longitudinal centre of buoyancy aligns under the longitudinal centre of gravity; transverse similarly at equilibrium heel.
IMO intact stability criteria (IS Code 2008): initial GM ≥ 0.15 m; area under GZ curve to 30° ≥ 0.055 m·rad; to 40° ≥ 0.09 m·rad; to 30° or 40° ≥ 0.03 m·rad; GZmax at ≥ 25°; max GZ ≥ 0.20 m.
Ship Design and Construction
Design spiral: displacement, main dimensions, form coefficients, power, and weight are iterated because each depends on the others; convergence, not sequence, is the design objective.
Admiralty coefficient C = Δ^(2/3)·V³/P relates displacement, speed and power; useful for first-pass power estimates when a similar-parent C is known.
Lightship weight breakdown is typically grouped into hull structure, outfit and furnishings, and machinery; deadweight covers cargo, fuel, fresh water, stores, crew and effects.
Scantling design follows classification society rules that derive required plate thickness and stiffener section modulus from load, span and permissible stress; IACS common structural rules harmonise bulk carrier and tanker minima.
Longitudinal strength is checked against still-water bending moment plus wave-induced bending moment; section modulus must satisfy both sagging and hogging conditions.
Framing systems: transverse framing suits shorter ships with many closely spaced frames; longitudinal framing with deep transverse webs suits long ships where longitudinal bending governs.
Freeboard is set by the International Convention on Load Lines; minimum bow height and tabular freeboard are adjusted for block coefficient, superstructure and sheer.
Structural continuity and avoidance of stress concentrations at hatch corners, bracket toes and openings govern fatigue and crack initiation in welded steel hulls.
Marine Engineering
Two-stroke slow-speed diesel: uniflow scavenging, crosshead construction, direct-coupled propeller; typical BMEP around 18–21 bar and shaft speeds 70–120 rpm for large bore units.
Indicated power per cylinder Pi = (p_i·L·A·n·k)/60 for a multi-cylinder engine; brake power = indicated power × mechanical efficiency.
Specific fuel consumption (SFCR) is quoted in g/kWh on a lower calorific value basis; ISO 15550/ISO 3046 reference conditions (25 °C ambient, 100 kPa, 30% RH) must be stated.
Turbocharger matching: exhaust gas energy drives the turbine; charge-air cooler and scavenge air pressure determine trapped air mass and thus achievable fuel/air ratio.
Fuel sulphur limits under MARPOL Annex VI: 0.50% m/m global from 1 January 2020; 0.10% m/m in Emission Control Areas; scrubber equivalent compliance permitted.
NOx Tier III applies to ships built on or after 1 January 2016 when operating in North American and US Caribbean ECAs and the Baltic and North Sea ECAs; Tier II elsewhere.
EEDI/EEXI and CII: attained EEDI must be below the required value; CII gives an annual operational carbon intensity rating A–E, with D and E requiring a corrective plan.
Propeller law: power varies approximately as shaft speed cubed and thrust as speed squared for a fixed-pitch propeller in open water; the vessel's resistance curve intersects the propeller curve at the service point.
Shipbuilding and Repair
Block construction sequence: steel preparation and blasting, cutting (plasma, laser, oxy-fuel), sub-assembly, panel/block assembly, grand block erection, then outfitting and commissioning.
Distortion control: balanced welding sequences, backstep and skip welding, and pre-setting reduce angular and buckling distortion in thin-plate panels.
Non-destructive testing of hull welds: radiographic and ultrasonic for volumetric defects; magnetic particle and dye penetrant for surface-breaking defects; acceptance per classification rules.
Docking and undocking: keel blocks, side blocks and bilge blocks must support the hull without over-stressing the structure; docking plan defines block positions and load limits.
Sea trials verify speed–power curve, manoeuvrability (turning circle, zig-zag, crash stop), endurance and anchor handling against contract specification.
Drydocking survey intervals: special survey every five years with annual and intermediate surveys; underwater inspection in lieu of drydocking (UWILD) requires class approval.
Hot work and tank entry during repair follow permit-to-work systems; gas-freeing and atmosphere testing for oxygen, hydrocarbons and toxic gases precede enclosed-space entry.
Repair specification should define extent, steel grade, welding procedure qualification, NDT coverage, coating system and acceptance criteria before work begins.
Professional Regulation and Ethics
Classification societies set technical rules and issue class certificates; flag states issue statutory certificates; the two roles are legally distinct even when the same society acts as recognised organisation.
IMO instruments relevant to design: SOLAS (safety), MARPOL (pollution), Load Lines, COLREG (collision avoidance), and the ISM Code (safety management).
Design approval and plan appraisal are performed against class rules and statutory requirements; any deviation requires documented equivalent or exemption approval.
Professional ethics: disclose conflicts of interest, do not certify work you have not verified, and do not accept pressure to alter calculations or test results.
Whistleblowing and reporting: safety defects affecting seaworthiness must be reported through the ISM non-conformity and flag state channels; suppressing them is a regulatory breach.
Confidentiality: client design data, test results and proprietary methods are protected; sharing requires written permission or legal compulsion.
Competence boundaries: signing off disciplines outside one's expertise without review by a qualified engineer is an ethical and often legal violation.
Records and traceability: calculations, NDT reports, trial data and approvals must be retained and auditable; falsification is grounds for professional sanction.
Naval Architecture
Displacement Δ = ρ·∇·C_B·L·B·T; block coefficient C_B = ∇/(L·B·T) uses the same length convention (LWL or LPP) consistently across all coefficients.
Froude number Fn = V/√(gL); a hull's wave-making resistance pattern is governed by Fn, so geometrically similar hulls at equal Fn have comparable wave resistance coefficients.
Reynolds number Rn = V·L/ν; frictional resistance coefficient uses the ITTC-1957 line C_F = 0.075/(log10 Rn − 2)².
Total resistance coefficient C_T = C_F + C_R + C_A + C_AA, where C_R is model-derived residuary resistance, C_A is hull roughness allowance, C_AA is air resistance.
Metacentric height GM = KB + BM − KG; BM = I/∇ where I is the waterplane second moment of area about the centreline. Positive GM indicates initial transverse stability.
Righting lever GZ = GM·sin φ for small angles; beyond about 10–15 degrees the full GZ curve from cross curves of stability must be used.
Free-floating trim and heel follow from moment equilibrium: longitudinal centre of buoyancy aligns under the longitudinal centre of gravity; transverse similarly at equilibrium heel.
IMO intact stability criteria (IS Code 2008): initial GM ≥ 0.15 m; area under GZ curve to 30° ≥ 0.055 m·rad; to 40° ≥ 0.09 m·rad; to 30° or 40° ≥ 0.03 m·rad; GZmax at ≥ 25°; max GZ ≥ 0.20 m.
Ship Design and Construction
Design spiral: displacement, main dimensions, form coefficients, power, and weight are iterated because each depends on the others; convergence, not sequence, is the design objective.
Admiralty coefficient C = Δ^(2/3)·V³/P relates displacement, speed and power; useful for first-pass power estimates when a similar-parent C is known.
Lightship weight breakdown is typically grouped into hull structure, outfit and furnishings, and machinery; deadweight covers cargo, fuel, fresh water, stores, crew and effects.
Scantling design follows classification society rules that derive required plate thickness and stiffener section modulus from load, span and permissible stress; IACS common structural rules harmonise bulk carrier and tanker minima.
Longitudinal strength is checked against still-water bending moment plus wave-induced bending moment; section modulus must satisfy both sagging and hogging conditions.
Framing systems: transverse framing suits shorter ships with many closely spaced frames; longitudinal framing with deep transverse webs suits long ships where longitudinal bending governs.
Freeboard is set by the International Convention on Load Lines; minimum bow height and tabular freeboard are adjusted for block coefficient, superstructure and sheer.
Structural continuity and avoidance of stress concentrations at hatch corners, bracket toes and openings govern fatigue and crack initiation in welded steel hulls.
Marine Engineering
Two-stroke slow-speed diesel: uniflow scavenging, crosshead construction, direct-coupled propeller; typical BMEP around 18–21 bar and shaft speeds 70–120 rpm for large bore units.
Indicated power per cylinder Pi = (p_i·L·A·n·k)/60 for a multi-cylinder engine; brake power = indicated power × mechanical efficiency.
Specific fuel consumption (SFCR) is quoted in g/kWh on a lower calorific value basis; ISO 15550/ISO 3046 reference conditions (25 °C ambient, 100 kPa, 30% RH) must be stated.
Turbocharger matching: exhaust gas energy drives the turbine; charge-air cooler and scavenge air pressure determine trapped air mass and thus achievable fuel/air ratio.
Fuel sulphur limits under MARPOL Annex VI: 0.50% m/m global from 1 January 2020; 0.10% m/m in Emission Control Areas; scrubber equivalent compliance permitted.
NOx Tier III applies to ships built on or after 1 January 2016 when operating in North American and US Caribbean ECAs and the Baltic and North Sea ECAs; Tier II elsewhere.
EEDI/EEXI and CII: attained EEDI must be below the required value; CII gives an annual operational carbon intensity rating A–E, with D and E requiring a corrective plan.
Propeller law: power varies approximately as shaft speed cubed and thrust as speed squared for a fixed-pitch propeller in open water; the vessel's resistance curve intersects the propeller curve at the service point.
Shipbuilding and Repair
Block construction sequence: steel preparation and blasting, cutting (plasma, laser, oxy-fuel), sub-assembly, panel/block assembly, grand block erection, then outfitting and commissioning.
Distortion control: balanced welding sequences, backstep and skip welding, and pre-setting reduce angular and buckling distortion in thin-plate panels.
Non-destructive testing of hull welds: radiographic and ultrasonic for volumetric defects; magnetic particle and dye penetrant for surface-breaking defects; acceptance per classification rules.
Docking and undocking: keel blocks, side blocks and bilge blocks must support the hull without over-stressing the structure; docking plan defines block positions and load limits.
Sea trials verify speed–power curve, manoeuvrability (turning circle, zig-zag, crash stop), endurance and anchor handling against contract specification.
Drydocking survey intervals: special survey every five years with annual and intermediate surveys; underwater inspection in lieu of drydocking (UWILD) requires class approval.
Hot work and tank entry during repair follow permit-to-work systems; gas-freeing and atmosphere testing for oxygen, hydrocarbons and toxic gases precede enclosed-space entry.
Repair specification should define extent, steel grade, welding procedure qualification, NDT coverage, coating system and acceptance criteria before work begins.
Professional Regulation and Ethics
Classification societies set technical rules and issue class certificates; flag states issue statutory certificates; the two roles are legally distinct even when the same society acts as recognised organisation.
IMO instruments relevant to design: SOLAS (safety), MARPOL (pollution), Load Lines, COLREG (collision avoidance), and the ISM Code (safety management).
Design approval and plan appraisal are performed against class rules and statutory requirements; any deviation requires documented equivalent or exemption approval.
Professional ethics: disclose conflicts of interest, do not certify work you have not verified, and do not accept pressure to alter calculations or test results.
Whistleblowing and reporting: safety defects affecting seaworthiness must be reported through the ISM non-conformity and flag state channels; suppressing them is a regulatory breach.
Confidentiality: client design data, test results and proprietary methods are protected; sharing requires written permission or legal compulsion.
Competence boundaries: signing off disciplines outside one's expertise without review by a qualified engineer is an ethical and often legal violation.
Records and traceability: calculations, NDT reports, trial data and approvals must be retained and auditable; falsification is grounds for professional sanction.
Naval Architecture
Displacement Δ = ρ·∇·C_B·L·B·T; block coefficient C_B = ∇/(L·B·T) uses the same length convention (LWL or LPP) consistently across all coefficients.
Froude number Fn = V/√(gL); a hull's wave-making resistance pattern is governed by Fn, so geometrically similar hulls at equal Fn have comparable wave resistance coefficients.
Reynolds number Rn = V·L/ν; frictional resistance coefficient uses the ITTC-1957 line C_F = 0.075/(log10 Rn − 2)².
Total resistance coefficient C_T = C_F + C_R + C_A + C_AA, where C_R is model-derived residuary resistance, C_A is hull roughness allowance, C_AA is air resistance.
Metacentric height GM = KB + BM − KG; BM = I/∇ where I is the waterplane second moment of area about the centreline. Positive GM indicates initial transverse stability.
Righting lever GZ = GM·sin φ for small angles; beyond about 10–15 degrees the full GZ curve from cross curves of stability must be used.
Free-floating trim and heel follow from moment equilibrium: longitudinal centre of buoyancy aligns under the longitudinal centre of gravity; transverse similarly at equilibrium heel.
IMO intact stability criteria (IS Code 2008): initial GM ≥ 0.15 m; area under GZ curve to 30° ≥ 0.055 m·rad; to 40° ≥ 0.09 m·rad; to 30° or 40° ≥ 0.03 m·rad; GZmax at ≥ 25°; max GZ ≥ 0.20 m.
Ship Design and Construction
Design spiral: displacement, main dimensions, form coefficients, power, and weight are iterated because each depends on the others; convergence, not sequence, is the design objective.
Admiralty coefficient C = Δ^(2/3)·V³/P relates displacement, speed and power; useful for first-pass power estimates when a similar-parent C is known.
Lightship weight breakdown is typically grouped into hull structure, outfit and furnishings, and machinery; deadweight covers cargo, fuel, fresh water, stores, crew and effects.
Scantling design follows classification society rules that derive required plate thickness and stiffener section modulus from load, span and permissible stress; IACS common structural rules harmonise bulk carrier and tanker minima.
Longitudinal strength is checked against still-water bending moment plus wave-induced bending moment; section modulus must satisfy both sagging and hogging conditions.
Framing systems: transverse framing suits shorter ships with many closely spaced frames; longitudinal framing with deep transverse webs suits long ships where longitudinal bending governs.
Freeboard is set by the International Convention on Load Lines; minimum bow height and tabular freeboard are adjusted for block coefficient, superstructure and sheer.
Structural continuity and avoidance of stress concentrations at hatch corners, bracket toes and openings govern fatigue and crack initiation in welded steel hulls.
Marine Engineering
Two-stroke slow-speed diesel: uniflow scavenging, crosshead construction, direct-coupled propeller; typical BMEP around 18–21 bar and shaft speeds 70–120 rpm for large bore units.
Indicated power per cylinder Pi = (p_i·L·A·n·k)/60 for a multi-cylinder engine; brake power = indicated power × mechanical efficiency.
Specific fuel consumption (SFCR) is quoted in g/kWh on a lower calorific value basis; ISO 15550/ISO 3046 reference conditions (25 °C ambient, 100 kPa, 30% RH) must be stated.
Turbocharger matching: exhaust gas energy drives the turbine; charge-air cooler and scavenge air pressure determine trapped air mass and thus achievable fuel/air ratio.
Fuel sulphur limits under MARPOL Annex VI: 0.50% m/m global from 1 January 2020; 0.10% m/m in Emission Control Areas; scrubber equivalent compliance permitted.
NOx Tier III applies to ships built on or after 1 January 2016 when operating in North American and US Caribbean ECAs and the Baltic and North Sea ECAs; Tier II elsewhere.
EEDI/EEXI and CII: attained EEDI must be below the required value; CII gives an annual operational carbon intensity rating A–E, with D and E requiring a corrective plan.
Propeller law: power varies approximately as shaft speed cubed and thrust as speed squared for a fixed-pitch propeller in open water; the vessel's resistance curve intersects the propeller curve at the service point.
Shipbuilding and Repair
Block construction sequence: steel preparation and blasting, cutting (plasma, laser, oxy-fuel), sub-assembly, panel/block assembly, grand block erection, then outfitting and commissioning.
Distortion control: balanced welding sequences, backstep and skip welding, and pre-setting reduce angular and buckling distortion in thin-plate panels.
Non-destructive testing of hull welds: radiographic and ultrasonic for volumetric defects; magnetic particle and dye penetrant for surface-breaking defects; acceptance per classification rules.
Docking and undocking: keel blocks, side blocks and bilge blocks must support the hull without over-stressing the structure; docking plan defines block positions and load limits.
Sea trials verify speed–power curve, manoeuvrability (turning circle, zig-zag, crash stop), endurance and anchor handling against contract specification.
Drydocking survey intervals: special survey every five years with annual and intermediate surveys; underwater inspection in lieu of drydocking (UWILD) requires class approval.
Hot work and tank entry during repair follow permit-to-work systems; gas-freeing and atmosphere testing for oxygen, hydrocarbons and toxic gases precede enclosed-space entry.
Repair specification should define extent, steel grade, welding procedure qualification, NDT coverage, coating system and acceptance criteria before work begins.
Professional Regulation and Ethics
Classification societies set technical rules and issue class certificates; flag states issue statutory certificates; the two roles are legally distinct even when the same society acts as recognised organisation.
IMO instruments relevant to design: SOLAS (safety), MARPOL (pollution), Load Lines, COLREG (collision avoidance), and the ISM Code (safety management).
Design approval and plan appraisal are performed against class rules and statutory requirements; any deviation requires documented equivalent or exemption approval.
Professional ethics: disclose conflicts of interest, do not certify work you have not verified, and do not accept pressure to alter calculations or test results.
Whistleblowing and reporting: safety defects affecting seaworthiness must be reported through the ISM non-conformity and flag state channels; suppressing them is a regulatory breach.
Confidentiality: client design data, test results and proprietary methods are protected; sharing requires written permission or legal compulsion.
Competence boundaries: signing off disciplines outside one's expertise without review by a qualified engineer is an ethical and often legal violation.
Records and traceability: calculations, NDT reports, trial data and approvals must be retained and auditable; falsification is grounds for professional sanction.