Marine - Vibrationdata Engineering Blog

Ship Propellers

July 20, 2026July 16, 2026 by Tom Irvine

Image credit: Merchant Navy Decoded — Propeller of Ship Walk along any harbor dry dock and you will notice that ship propellers almost always have between three and six blades, with four and five being the most common for merchant vessels. The blade count is… Read more

Wind Turbine Blade Number Trade-offs

July 20, 2026July 13, 2026 by Tom Irvine

Introduction Nearly every utility-scale wind turbine built today has three blades. This was not inevitable. One-blade and two-blade machines were built and fielded in the 1980s and 1990s, and multi-blade rotors dominated the farm windmill era for a century. The three-blade configuration won a genuine… Read more

Surface Ship Shock, SRS, DDAM, MIL-DTL-901, UNDEX

July 22, 2026July 7, 2026 by Tom Irvine

The image shows a MIL-S-901D Barge Test. A reader recently wrote in with two requests: (1) blog posts on surface ship shock and shock response spectra derived from acceleration data, and (2) coverage of underwater explosion (UNDEX) shock effects on submerged components such as batteries.… Read more

Stop Drilling for Fatigue Crack Arrest

July 20, 2026July 5, 2026 by Tom Irvine

One of the most counterintuitive repair techniques in structural engineering is also one of the oldest: to stop a fatigue crack from growing, you drill a hole at its tip. Adding material loss to an already cracked structure seems like exactly the wrong prescription —… Read more

Corrosion-Induced Concrete Cracking — Mechanisms and Mitigation

July 20, 2026July 4, 2026 by Tom Irvine

By Tom Irvine | Marine Corrosion Series — Madeira, Portugal (ISO 9223 Category C5) The photograph below was taken in Funchal, Madeira on 4 July 2026. It shows the corner bracket connection of a painted mild steel railing to a rendered concrete fascia on a… Read more

Stainless Steel Straw Residual Stress

July 20, 2026July 4, 2026 by Tom Irvine

By Tom Irvine While enjoying a glass of orange juice at an outdoor café in Madeira, Portugal on a sunny Independence Day morning, I noticed the reusable stainless steel straw resting across the glass — its elegant curved bend a perfect reminder that one of… Read more

Marine Corrosion Part 2 — Hollow Sections and Coating Failure

July 20, 2026July 3, 2026 by Tom Irvine

This is the second post in a series on marine corrosion observed at coastal infrastructure in Madeira, Portugal, July 2026. Part 1 covered a severely corroded bolt and nut at a seaside retaining wall. Here we examine two additional specimens from the same location: a… Read more

Carbon Steel Marine Corrosion

July 20, 2026July 3, 2026 by Tom Irvine

Photograph taken at a seaside retaining wall in Madeira, Portugal, July 2026. The bolt and nut shown are carbon steel — heavily corroded after prolonged exposure to the Atlantic marine environment.Figure 1. Severely corroded carbon steel bolt and nut at a seaside retaining wall, Madeira,… Read more

Marine Propeller Cavitation

July 20, 2026September 13, 2021 by admin

Cavitation is the formation of vapor bubbles within a liquid at low-pressure regions that occur in places where the liquid has been accelerated to high velocities, as in the operation of centrifugal pumps, water turbines, and marine propellers. The water jet slows down after traveling… Read more