Accident at Edinburgh dockyard

Not so much flat area on the bottom of that vessel either so blocking not helping as much as it would on a conventional vessel.

On television, I just saw a report about the dry-dock of the frigate ā€˜HDMS Absalonā€™ in a Danish shipyard.

Without a large flat bottom, they had just one central line of blocks, about 2/3 meters large and high (high, because of the deeper sonar bulb). Indeed, they needed side shoring on top of the hull.

No they are steel with a rubber face at the ship and tapered wooden chocks against the dock wall.

Donā€™t think so, Imperial dock was built in 1913 and still use the original pumps albeit it with electronic drives to the DC motors. She had a new dock gate fitted in 2018. She has been in continuous use and I was there in 2015, 2016, 2019, 2020 and the last time in 2021. Planning to go back in 2024, 2025 & 2026.

I was replying to the Singapore post

There is a youtube clearly showing the aft ones are steel and the forward ones are wood even the curve in them

Sorry to disagree but have never seen wooden side shores at either Dales Aberdeen or Dales Leith. Short wooden shores are used under the guard plate on our Voith tugs.

Ok my bad!

Ok let me find the vid is sure looks like wood and not much on the port side which is still hanging from the safety lines.
IMHO they were more important on this particular vessel due to the bottom shape

EDIT

4.17 what do you reckon the 2 fwd ones look like?
I was just guessing.

The strength of wood under compression can be very high, comparable to steel in some cases.

Strength of Steel Vs. Wood | Hunker

Pressure Damage

The ā€œPortlandā€ experiment determined that the wooden support structures for the concrete suffered their first major damage at 3500 pounds of force against the wood supports, which was identical for steel. The first major damage showed a structural displacement of .51 inches for wood, and a slightly greater .54 inches for steel, meaning that the damage at 3500 pounds was slightly worse for steel than wood.

that wood explains all the tower cranes made from wood
end to end compression is not where I would use wood

It would be interesting to see the side shores on the starboard side of the ship.
The visible port side shores were under traction, where the traction strength of the installation is the limiting factor.

The starboard side shores were under compression, where the compression strength is not the limiting factor, but the buckling resistance is. The latter one is much lower, for those long and ā€˜thinā€™ liaisons.

It looks, as inside of the metallic tubes, there were cables to counter the traction forces. If these cables were not under pretension, they would permit the vessel to incline some small way. The tubes on the starboard sides were probably on contact. Hence, the starboard tubes would immediately take the full inclining forceā€¦ and possibly fail.

It seems the side shores were fixed low on the hull; this makes a high lever against strong winds on the superstructure or a displacement or removal of large weights inside the ship.

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My sincere apologies, have had a senior moment as one of my Chief Engineers has reminded me this morning that when we were in dd in 2020 we were double docked and the other ship had wooden shores. He also said that he thought that Dales had a limited number of steel shores. Our boats have never had wooden shores and we are not often double docked so apologies once again as should have looked at my dad pics. D

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do you think the wooden shores and the low number were ok to hold that boat up especially where there is very little support against rolling due to the shape?

That has been the discussion here but without any evidenceā€¦.

Hope they get it sorted as Iā€™ve just booked us in for next year :smile:

Hereā€™s a photo of the other ship in the drydock:

Looks like steel cylindrical shaped beams to support the horizonal load.

Hereā€™s the Petel.

Looks like wooden beams. They would be subject to failure under compression due to buckling, similar to the way a column would fail.

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Interesting case for me having dry docked many ships. Every ship has a docking plan. The ship rests on blocks at Center Line, CL and a few taller ā€œbilgeā€ blocks P&S to stabilize the ship in dock. Main weight >95% is taken by the CL blocks. The bilge blocks carry little weight (<5%), they just prevent rotation. Horizontal shoring is normally not required. So why did ā€œRV Petrelā€ flip over in dock? Maybe the bilge structure above the bilge blocks broke the hull? The ship was rotten? Or the CL blocks failed?

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I donā€™t know. When and were did that happen?

Buckling is a type of failure that occurs in all types of materials.

With that said, they might have been better off using tension only supportsā€¦such as cables.

Wood doesnā€™t buckle.