USCG Marine Science Technician (MST) Service Wide Exam (SWE) Practice

The acceptable amount of wearing or erosion of a vessel's hull is deemed to be 25%. This standard is established to ensure safety and structural integrity, allowing for some degree of wear without compromising the vessel's performance or leading to potentially hazardous conditions. A hull that is excessively worn can lead to leaks, reduced buoyancy, and structural failures, danger to crew and cargo, and possible environmental damage.

Each of the lower percentages reflects a more conservative approach to hull maintenance and may not permit sufficient wear that can be observed during normal operational conditions. Allowing 25% erosion acknowledges the realities of marine environments where hulls face constant wear from abrasives such as sand, salt, and biological growth. Understanding this guideline helps ensure that regular inspections and maintenance can be performed while permitting some level of natural wear that does not endanger vessel integrity.