Burgess COMMENTARY

Peter Burgess

Q ... Why do Nimitz class aircraft carriers flex when they hit large waves? Are there any other peculiarities in large storms? Andswer ... Stephen Carey As an example on the other answers, I was in the duct keel of a large bulk carrier (it was large in those days, around 110,000dwt) which was 260.61 m (855ft) long. This rather tight passage has a string of lights all the way up it and rails on which a trolley (self propelled by a rope over a pulley) allows you to lie on it and run up and down the passageway. It’s not possible for someone of my height (6′) to stand up in comfortably. We were in bad weather and the ship was pitching a fair bit - I had noticed the tubular expansion sleeves on the deck handrails were sliding in and out. The duct keel was knee deep in seawater and hydraulic oil, and the string of lights converged in the distance 200m away. As the ship sagged on hitting a wave, the necklace of lights rose up at the fore end and disappeared from view. As the ship went over the wave, it hogged and the necklace of lights came back into view again, were level for a few moments, before disappearing again “downhill”. I think that a duct keel is the best place to view this phenomenon! This movie shows it quite well - a Maersk container ship in rough weather, though the effect is more pronounced in the likes of a duct keel. Stress and effect on a vessel in severe weather conditions 2,550,874 views Claus Tuxen Published on Apr 8, 2014 Stress and effect on a vessel in severe weather conditions. Recorded during passage from Suez Canal to Singaporre, recorded in June 2008. Ships in Storm - Terrifying Monster Waves