- S-CAT stands for Shipboard Corrosion Assessment Technician, a credential governed by AMPP.
- The written exam is 50 multiple-choice questions in 90 minutes, delivered via Pearson computer-based testing.
- Domain 4 (Corrosion Protection System) is the largest content area at 22-26% of the exam.
- Candidates need 1.5 years of applicable work experience plus a 5-day in-person course before sitting the exam.
What Is a S-CAT?
A Shipboard Corrosion Assessment Technician, universally shortened to S-CAT, is a credentialed professional qualified to systematically evaluate corrosion on vessels, assess the condition of protective coatings and cathodic protection systems, inspect ballast and cargo tanks, and produce inspection records that drive maintenance decisions for ship operators and owners. The designation is not an informal job title - it is a formal certification issued by the Association for Materials Protection and Performance (AMPP), the global authority on corrosion science and protective coatings.
In practical terms, a certified S-CAT is the person who climbs into a ballast tank, reads the condition of every structural member, quantifies corrosion grades, checks coating breakdown, evaluates cathodic protection anodes, and translates all of that into a scored, defensible inspection report. Without that structured assessment, ship operators are flying blind on one of the most expensive maintenance problems in the maritime industry.
If you want a deeper look at the credential from a career and value perspective, our companion article S-CAT Certification covers the full landscape of what holding the designation means professionally.
What S-CAT Stands For - and Why Each Word Matters
The acronym breaks down precisely:
- Shipboard - the scope is confined to vessels: naval ships, commercial cargo vessels, tankers, ferries, and any floating structure subject to marine corrosion environments.
- Corrosion Assessment - the role is evaluative, not remediation. An S-CAT does not necessarily apply coatings or install anodes; they assess, grade, and document corrosion status against defined criteria.
- Technician - the credential is technician-level, meaning it is hands-on, field-oriented, and distinct from higher-level engineering or inspector roles in the AMPP credential hierarchy.
Understanding the scope implied by each word tells you exactly what the exam will test. You will not be asked to design a cathodic protection system from scratch, but you absolutely must know how to evaluate whether an existing CP system is performing correctly. For a more etymological breakdown, see S-CAT Meaning and What Does S-CAT Stand For?
Who Hires S-CAT Technicians?
Demand for certified S-CAT technicians comes from several distinct sectors of the maritime industry:
- Naval commands and defense contractors - The U.S. Navy and allied navies require structured corrosion inspections on surface combatants, amphibious vessels, and support ships. Defense maintenance contractors frequently list S-CAT certification as a requirement or strong preference for shipyard inspection roles.
- Commercial shipping companies - Tanker operators, bulk carrier owners, and container lines use corrosion assessments to manage hull integrity, satisfy class requirements, and control dry-docking costs.
- Shipyards and dry-dock facilities - Repair yards need technicians who can assess incoming vessels, prioritize coating and structural work, and sign off on inspection documentation.
- Third-party inspection firms - Independent marine inspection companies hire S-CATs to provide objective, credentialed assessments for buyers, insurers, and regulatory bodies.
- Classification societies - While classification surveyors carry their own credentials, they work alongside S-CAT technicians during statutory surveys.
For a full picture of job titles, employers, and how the credential positions you in the labor market, read our S-CAT Jobs guide.
The S-CAT Exam Structure: What You Will Actually Face
The S-CAT certification process involves two distinct evaluations that candidates must pass:
The Written Exam
The S-CAT Written Exam is delivered as computer-based testing (CBT) through Pearson. Here are the specifics every candidate should know before scheduling:
| Exam Detail | Specifics |
|---|---|
| Number of Questions | 50 |
| Total Seat Time | 90 minutes |
| Nondisclosure Agreement | 4 minutes (included in the 90) |
| System Tutorial | 6 minutes (included in the 90) |
| Effective Testing Time | 80 minutes for 50 questions |
| Question Format | Multiple choice, including select-all-that-apply |
| Scoring | Pass or Fail |
| Post-Exam Feedback | Domain-strength feedback available in AMPP profile |
| Test Code | NACE-SCAT-001 |
| Prep Guide Version | March 2026 |
The select-all-that-apply format deserves special attention. Unlike standard multiple-choice questions where one answer is correct, these items require you to identify every correct option - partial credit is not awarded. This format rewards thorough knowledge rather than process-of-elimination guessing. Practicing with realistic CBT-style questions is the fastest way to build comfort with this format; the S-CAT practice test platform replicates both question types.
The Practical Exam
The practical exam is delivered as part of the 5-day in-person Shipboard Corrosion Assessment Training course. This is not a sit-at-a-desk assessment - candidates demonstrate hands-on competency in applying visual assessment methods, using inspection tools, and evaluating corrosion conditions against standardized rating criteria. Earning 3.4 CEUs/PDHs, the course is conducted in English and combines expert-led instruction with the practical examination component.
The Eight Content Domains: Where the Exam Weight Lives
The S-CAT Written Exam Preparation Guide organizes testable content into eight domains. Understanding the weight of each domain is the foundation of efficient exam preparation. For a comprehensive breakdown of every domain, including specific topics and study strategies, see the S-CAT Exam Domains 2026: Complete Guide to All 8 Content Areas.
Domain 4: Corrosion Protection System (22-26%)
The single largest domain. Expect questions on coating systems (types, application, failure modes), cathodic protection (impressed current and sacrificial anode systems), and how to evaluate the effectiveness of both. Candidates must understand the interaction between coatings and CP - not just each system in isolation.
- Coating system types and selection criteria for shipboard environments
- Sacrificial anode vs. impressed current CP system evaluation
- Coating breakdown classification and grading standards
- Interaction effects between damaged coatings and CP demand
Domain 1: Visual Assessments (18-22%)
The second-largest content area. Visual assessment is the core field skill of an S-CAT - recognizing corrosion types, grading severity, and documenting findings using standardized rating scales. This domain tests both the what (types of corrosion) and the how (systematic inspection methodology).
- Corrosion type identification: pitting, crevice, galvanic, erosion-corrosion
- Standardized grading and rating scales
- Systematic compartment inspection sequencing
- Documentation and photographic records
Domain 5: Maintenance and Manage Inspection Results (16-20%)
The third-largest domain covers what happens after the inspection: interpreting results, prioritizing maintenance actions, and managing records. Candidates need to understand how inspection findings translate into maintenance decisions and reporting requirements.
- Prioritization frameworks for maintenance actions
- Inspection record management and retention
- Communicating findings to ship operators and management
Domain 6: Tank Inspection (10-14%)
Ballast tanks and cargo tanks have unique inspection challenges: confined space entry, access limitations, and specific corrosion patterns. This domain covers tank inspection procedures, safety requirements, and grading methodology specific to tank environments.
- Confined space entry and safety protocols
- Tank structure nomenclature and access planning
- Inspection sequencing within tank compartments
The remaining domains - Domain 7: Total Tank Scoring (4-8%), Domain 2: Corrosion Control Methods (4-8%), Domain 3: Evaluation Tools and Equipment (4-8%), and Domain 8: General Knowledge (6-10%) - collectively account for approximately 22-34% of the exam. Do not neglect them; at 50 questions total, even a 4-8% domain represents 2-4 questions that can determine your outcome.
Individual deep-dives are available for Domain 1: Visual Assessments, Domain 2: Corrosion Control Methods, Domain 3: Evaluation Tools and Equipment, and Domain 4: Corrosion Protection System.
Prerequisites and Registration: What You Need Before You Can Sit
The S-CAT is not an open-registration exam. AMPP's certification pathway requires candidates to satisfy several conditions:
- 1.5 years of applicable work experience in a corrosion assessment or related maritime/industrial role.
- Completion of Shipboard Corrosion Assessment Training - the 5-day in-person course that also delivers the practical exam.
- Successful completion of the Practical Exam (administered during the course).
- Ethics for the Corrosion Professional training, or an equivalent approved course.
- AMPP Terms of Service agreement.
- Written Exam via Pearson CBT (scheduled separately after course completion).
No formal course prerequisites are listed on the course page, but AMPP recommends a background in basic science and chemistry. Candidates without that background should address it before the course - showing up without foundational chemistry knowledge will make the 5-day curriculum significantly harder to absorb.
Keeping Your Certification Current
The 3-year validity window sounds generous, but the PDH requirement demands year-round attention. At 8 PDHs per year, candidates who wait until the final months of their certification cycle face a scramble to accumulate hours. AMPP-approved activities that generate PDHs include technical conferences, webinars, relevant coursework, and documented on-the-job training activities - but each must meet AMPP's criteria to count.
Work experience is also non-negotiable for renewal. The 1.5-year requirement means that if you step away from corrosion assessment work entirely, you may need to rebuild your eligibility before renewing. This structure reinforces that the S-CAT is designed to credential active practitioners, not credential-collectors.
Preparing Smart: Allocating Your Study Time Across Eight Domains
Generic study advice is easy to find. What matters for the S-CAT is understanding which domains to prioritize and why. Here is a domain-weighted approach to a 4-week preparation window (assuming the course is already complete):
Domain 4: Corrosion Protection System (22-26%)
- Master coating system types and failure mode identification
- Review sacrificial anode sizing and placement criteria
- Practice grading coating breakdown using reference standards
- Take domain-specific practice questions at S-CAT Exam Prep
Domains 1 and 5: Visual Assessments + Maintenance (18-22% and 16-20%)
- Drill corrosion type identification using photographic references
- Review standardized rating scales and grading criteria
- Study maintenance prioritization logic and record management
Domains 6, 8, and 7: Tank Inspection + General Knowledge + Scoring (10-14%, 6-10%, 4-8%)
- Review confined space procedures and tank inspection sequencing
- Cover General Knowledge domain - maritime terminology, safety, and regulatory awareness
- Study Total Tank Scoring methodology and calculation logic
Domains 2 and 3 + Full Exam Simulation
- Corrosion Control Methods: cathodic protection techniques, coating application methods
- Evaluation Tools and Equipment: instrument calibration, measurement tools, and their proper use
- Complete timed 50-question practice exams to build pacing (80 effective minutes)
- Review domain-weakness areas identified through practice test analytics
The spaced repetition principle applies directly here: revisit Domain 4 material briefly during weeks 2 and 3 to prevent decay of your highest-value content. Our S-CAT Study Guide 2026: How to Pass on Your First Attempt provides a more granular breakdown of study resources and topic-level priorities.
Key Takeaway
Domain 4 (Corrosion Protection System) and Domain 1 (Visual Assessments) together represent 40-48% of the written exam. If your study time is limited, these two domains deliver the highest return per hour invested - but the exam's select-all-that-apply format means shallow knowledge will not be enough in any domain.
Frequently Asked Questions
S-CAT stands for Shipboard Corrosion Assessment Technician. It is a certification issued by AMPP (Association for Materials Protection and Performance) that qualifies professionals to conduct structured corrosion assessments on vessels, including visual inspections, coating evaluations, cathodic protection assessments, and tank inspections. More on the acronym at What Does S-CAT Mean?
The S-CAT Written Exam contains 50 questions and the total session is 90 minutes. That 90 minutes includes 4 minutes for the nondisclosure agreement and 6 minutes for a system tutorial, leaving approximately 80 minutes of effective testing time. Questions are delivered as computer-based multiple choice, including some select-all-that-apply items, through Pearson testing centers.
Candidates must have 1.5 years of applicable work experience, complete the 5-day Shipboard Corrosion Assessment Training course (which includes the practical exam), complete Ethics for the Corrosion Professional or equivalent training, pass the practical exam, and agree to AMPP's Terms of Service. The written exam at Pearson is then the final step. No formal course prerequisites are required, but basic science and chemistry knowledge is strongly recommended.
Domain 4, Corrosion Protection System, is the largest content area at 22-26% of the exam. Domain 1, Visual Assessments, is second at 18-22%. Together these two domains can account for up to nearly half of all exam questions, making them the priority areas for study time allocation.
The S-CAT certification is valid for 3 years. Renewal requires a recertification application that must be approved by AMPP, documentation of 1.5 years of applicable work experience during the certification period, and 24 total PDHs accumulated at 8 PDHs per year. Renewal fees are $295 for AMPP members and $525 for nonmembers unless otherwise noted by AMPP. See the Is the S-CAT Certification Worth It? Complete ROI Analysis 2026 for context on the long-term value of maintaining the credential.