Weekly update – 25 March 2022
Our next delivery of rock is scheduled for this Saturday and Sunday (26-27 March) during the day – with the tides in two sessions each day 03:00 to 11:00 and 16:30 to 23:00. Rock installation will take place both days from 06:00 to 12:30. There may also be some work breaking up the existing defence structure.
We are using two size grades of rock to create the revetment (sloped structure) at Southsea Castle. We are placing ‘core’ rock on top of the geotextile (the black material seen in the photo to the left). This is best described as a base of smaller rocks, each one weighing between 60 and 300 kilograms. On top of this, two layers of larger rock armour are placed and interlocked. The grading ranges from 1-3 tonnes with some on the extreme upper limit weighing up to 4 tonnes (for some context, that’s about the weight of an average Indian elephant!).
The tide is high
Interested in the tidal movements that influence the timing of our rock works? Check out the Portsmouth tide times here.