Sep 22

More news from Allure’s sea trials | chairmans-blog

More About the Sea Trials

In my last posting, Harri gave an overview of the sea trials.  Since then he has provided some more of the details which I thought were interesting. 

First, please note this chart.  It looks a little bit like an Etch-A-Sketch such as the one my (gorgeous) grandchildren like to play with.  Actually, it shows the track that Allure of the Seas followed during her sea trials.  At first, I was beginning to question their navigation skills remembering that the ship still belongs to STX and their crew were in charge.  Then I realized that they were intentionally taking the ship into difficult waters in order to make the tests as complete and stressful as possible.


Allure’s Track


Other tidbits from the trials:

  • The top speed of the ship with 24.36 knots.  This was at 100% of “MCR” (i.e. full power) and an 8.7 meter draft.  The conditions included 2 meters significant wave height and wind speeds of 9 meters per second.  It always amazes me that such a large ship can be so fast and nimble.
  • While that was the top speed, we define a slower “maximum cruising speed” which includes a cushion for the unexpected.  Our experience is that we always expect that the unexpected can be expected to occur.  For cruising speed, we measure the speed of the ship using only 78% of MCR.  On this basis, the maximum cruising speed was 22.3 knots which is 0.3 knots better than the contractual requirements.
  • One of our key considerations is noise and we have 300 major measuring points throughout the ship.  We measure more points than this, but these are the 300 most important.  During the sea trial, 298 of them exceeded specification but two of them were below our requirements and will need to be fixed before delivery.
  • Similarly, we have 175 main measuring points for vibration and every one of them exceeded spec. 
  • This was the time to test all the engines, generators, diesels, motors, etc.  All of them are tested at full load and under stress conditions – endurance, blackout and with artificially induced anomalies.  Remarkably, only one deficiency was noted out of all these tests and the problem was fixed even while the ship was still undergoing the trials.
  • Maneuvering is a big issue on any ship, but we are especially careful with Allure.  The ship’s steering, radar tracking systems and dynamic positioning were all tested under stress conditions.  All performed well.  We have added a wave radar system simply to track the sea state at different times, but this has not been installed and could, therefore, not be tested.  However, the two new side radars were both commissioned and tested successfully.

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