CMI Evidence Collection & Forensic Analysis 3

Question 1

When a vessel's Voyage Data Recorder (VDR) is secured after a casualty, what is the first priority before downloading data?

Accepted Answer

Document the capsule's condition, seal number, and create a bit-for-bit forensic copy before analysis

Answer

Creating a verified forensic image preserves the original data integrity and allows the original capsule to remain untouched as the evidentiary master copy.

Question 2

In a flooding casualty investigation, an investigator discovers a through-hull fitting with a cracked seacock body. What metallurgical analysis would best determine if the failure was pre-existing or sudden?

Accepted Answer

Scanning electron microscopy (SEM) to examine fracture surfaces for fatigue marks, stress corrosion, or overload failure patterns

Answer

SEM examination of fracture surfaces can distinguish fatigue cracks (beach marks, striations) from sudden overload failures, establishing whether the defect was progressive or acute.

Question 3

A marine investigator needs to establish the exact time a vessel's engine room bilge alarm activated. Which source provides the most reliable timestamp for this determination?

Accepted Answer

The integrated alarm and monitoring system (AMS) electronic log with UTC-synchronized timestamps

Answer

An AMS electronic log provides automated, UTC-synchronized timestamps that are more reliable than human recollection or manually recorded entries.

Question 4

During a collision investigation, both vessels' AIS tracks are examined. What limitation of AIS data must be considered when reconstructing the incident?

Accepted Answer

AIS position reports are transmitted at intervals, so the track interpolates movement between transmissions and may not reflect instantaneous maneuvers

Answer

AIS transmits at intervals based on speed and vessel type, meaning the reconstructed track interpolates position between actual transmissions and can miss rapid course or speed changes.

Question 5

An investigator collects fabric samples from a suspected arson fire aboard a yacht. What is the proper method for preserving these samples for accelerant detection?

Accepted Answer

Seal samples in clean, unused paint cans or nylon bags to prevent accelerant evaporation

Answer

Airtight containers such as clean paint cans or nylon evidence bags prevent volatile accelerant compounds from evaporating before laboratory analysis.

(CMI) Certified Marine Investigator Practice Test

(CMI) Certified Marine Investigator Practice Test

CMI Evidence Collection & Forensic Analysis 3