Fatigue contributes to rudder damage

Lookout! Issue 38, July 2018

A fatigued skipper, and anchoring in an unfamiliar area during darkness, contributed to rudder damage on a fishing vessel off the East Coast recently.
“Unsafe for navigation” – the chart plotter the skipper relied on to find a safe anchorage.
Maritime New Zealand © 2020
“Unsafe for navigation” – the chart plotter the skipper relied on to find a safe anchorage.

The skipper had left port at 5.30pm and headed north to get into position for fishing the next day. But in the early morning he found his usual anchorage being used by other trawlers. So instead the skipper headed further north to a more remote coastline and tried anchoring in a relatively uncharted area, 400 metres from shore.

The rudder was damaged when the vessel hit rocks
The rudder was damaged when the vessel hit rocks.
Maritime New Zealand © 2020

As he was getting into position, using the vessel’s echo sounder and chart plotter, he noticed a rock awash on his port side. The stabilizer arm became fast on the rock, causing the vessel to pivot.

As the skipper reversed to unhook the stabilizer arm, the steel trawler itself hit the rock. Later that morning a diver confirmed that the rudder was damaged, and the vessel was towed back to port.

The skipper told investigators that the usual echo sounder and chart plotter were not working at the time, as there was an issue with the transducer. He may have not had the chart plotter zoomed in enough when operating close to shore.

Fatigue was also likely to have been an issue, as the turn-around in port had only been a couple of hours. The skipper confirmed he only had about 4.5 hours sleep in the 24 hours prior to the collision.



  • Lack of sleep can affect judgment and risk the safety of the crew and vessel.
  • This skipper only had a few hours sleep, during a quick turn-around in port, after being out fishing all day and before heading out again.
  • Fatigue management is part of an operation’s Maritime Transport Operations Plan (MTOP). It is vital for the safety of all onboard that the skipper and crew stick to the processes that the operator has included in the plan.
  • This skipper accepts he should have anchored further off-shore as he did not know this area of the coastline. He says he should also have paid more attention to the contour lines on the chart plotter as he was preparing to anchor.
  • Misinterpretation of the depth of the contour lines on the chart plotter may have contributed to the incident. Skippers must ensure they have a thorough understanding of navigation equipment and how to use it – including temporary replacement systems.
  • Skippers should not rely on chart plotters alone to identify submerged rocks when operating close to shore. Paper charts and local advice and experience should be a part of the process. As noted during the investigation when the chart plotter was zoomed in it read ‘UNSAFE FOR NAVIGATION’ – which is common for a number of chart plotters used in the industry.

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