A population, from the archive

Towing Vessel, built 1970s, any size

2,148 hulls · 661 operators are present and the largest holds 3% of the hulls

What the record shows for this population

Hulls in the cohort	2,148
Median recorded inspections per hull	24
Median recorded deficiencies per hull	3
Hulls with any recorded deficiency	69%
Hulls appearing in any casualty investigation	72%

Medians, not means: a single hull with hundreds of recorded deficiencies would drag a mean into implying a severity the record does not support. Every figure is a count or a median of what the Coast Guard wrote down.

What this is not

This is a fact about a population, not a judgement about any vessel or any operator. Maury does not score, rate, or grade vessels, and it publishes no statistic for a named operator. This cohort is published because no single operator’s record can be read out of it: 661 operators are present and the largest holds 3% of the hulls. A cohort that fails that test is not published and is not widened until it passes.

A higher median can mean hulls were inspected more often rather than found worse. Maury’s own published finding is that recorded deficiency history shows no measurable relationship to later casualties.

Cohort definition

Vessel type as the Coast Guard classes it; build year from the record; overall length from the USCG vessel service where the band is not “any size”. Recomputed from the archive every time the site is built. Coverage, known gaps and method.