Side haul railway dry docks
Ship transfer machinery
Chains, rollers and maintenance
Bridles roller system
Restoration & enlargement
Vertical lifting vs. inclined ways
More and more new vessels with unconventional hull shapes are being constructed.
When these are to be drydocked, they often pose difficult problems
of stability, load concentration, access, and blocking. Among
such craft are hydrofoil vessels, catamarans, and surface warships
with deep-draft propellers and sound detecting devices.
Railway dry dock cradles can be designed and built so as to cope
with some of these problems. The outshore section can have an
access basin to receive sonar domes or similar protuberances.
The wedge shape of the cradle provides the space in the undercarriage
to put in a basin that remains flooded while the dock is operative
and is only dewatered in the full-up position when needed. At
sites with adequate tide range, the basin can be omitted so long
as the cradle beams are designed to be removable in way of deep
Where the undercarriage is shallow, spaces located in the cradle
runners can be inserted to provided room for rudders and propellers.
Hydrofoil vessels having fixed foils can be drydocked easily
on railway dry docks by allowing the extending foils to project
beyond and below the cradle deck. In other types of dry docks
the platform must be made wider than the foil span, which makes
the facility too costly.
Cradles equipped with releasing bilge and keel blocks, sliding
retractable keel blocks and means to remove blocks, beams or uprights
easily, permit many types of vessels to be accommodated with minimum
loss of time and minimum manpower.
Next: Construction procedures