Rosyth Dockyard 17 – Caissons manufactured at North Queensferry

 
As well as the four caissons manufactured at Rosyth, William Arrol and Co manufactured a further four caissons at
North Queensferry. Presumably to augment the limited working space in the inner basin at Rosyth. Work must have started in 1912; these photographs are dated February and March 2013.

Three sliding caissons under construction next to the Railway Pier at North Queensferry.

Caisson F almost complete on 31st March 2013 next to the Railway Pier at North Queensferry.
The caisson is lying on its side, with its base to the right. The folding top deck has still to be added.

The above image rotated and cross section diagrams of a sliding caisson

Split elevation diagrams of a sliding caisson – the right side is a sectional elevation.
This diagram shows the locations of the Air Chambers which provide buoyancy,
the Ballast and Emergency Tanks and the Divers Trunk and Ladder.

Simplified elevation of a sliding caisson

The simplified diagram shows the main internal components of a sliding caisson.

The divers’ trunks allow the bottom section of the caisson to be inspected.
If the ballast tanks need to be inspected, the emergency tanks are used and the ballast tanks can be pumped dry.

Another view of sliding caissons C, D and F at North Queensferry