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114:, opened. Early docks were of simple construction: a single lock gate isolating them from the tidal water. The gates were opened during the last hour of the rising tide, giving a short window of opportunity to let ships in on the rise and releasing outgoing ships while the tide was on the turn. The gates were closed at top of tide to maintain levels within the dock. Although this short opening period may have seemed disruptive, any attempt at longer opening might allow dock water-level to fall with the
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175:. Although linked by locks to the harbour and the river, the intention was that the basin would itself be used as an entrance lock: rather than locking each ship through one-by-one, ships could wait for the tide inside the basin and then the outer lock gates could both be opened allowing all to leave and arrive together. For a port with such a convoluted and tide-dependent approach as Bristol's, any easing of access was valuable.
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are usually arranged as a chevron. and can only hold back higher water in one direction, which must always be from within the dock. A small but significant example of this is the locking system on the River Darent in
Dartford, now in restoration and which were fully operational between 1899 and 1983.
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on the floor of the dock prevents the level dropping below a certain point, meaning that the ships in the dock remain afloat, although they still fall with the first ebb of the tide. Half tide docks were only useful for ships of shallow draught, in areas with a large tidal range. The tide must rise
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was opened. This was the first commercial floating dock, isolated by a lock rather than a single lock gate. This allowed the dock's water level to be maintained and, more importantly, it increased the time for which tidal access was possible. However the lock was only 121 ft long and this
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As the harbour now need never be connected directly to the tidal waters, its water level could be held constant, without even the small variation of the hours around high tide. At
Bristol, Jessop controlled the height of the harbour water by a broad
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Maintaining this higher level requires a supply of water. In some cases this is available from a river flowing into the harbour. This was the case for
Bristol, at least initially, with the
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As one of the first industrialised ports, Liverpool was at the forefront of dock development from the early 18th century. A network of inter-linked docks developed along the length of the
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or
Greenland Dock, built in London at the end of the 17th century. This was not a commercial dock and had no warehouses, but was intended solely for ship replenishment and refitting.
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permits transfer near top of tide whether it be neap or spring. Generally inbounds enter on the rise and outbounds on the fall. In practical use, the operation of
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in East London has used a bi-directional system since the year 2000 permitting boats to transfer between the tidal Bow Creek and
Limehouse Cut.
218:. Ships could move through the interlinked docks 24 hours a day without moving into the tidal River Mersey, which would necessitate a pilot.
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The tourist's companion, or, The history of the scenes and places on the route by the rail-road and steam-packet from Leeds and Selby to Hull
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Floating docks are generally maintained at a level at least as high as the highest tide. Apart from any considerations of navigation,
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298:, a simpler version, where a fixed sill retains some water within the dock to allow ships to float, but at varying height.
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347:"A Study of Changes in High Water Levels and Tides at Liverpool during the Last Two Hundred and Thirty Years"
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183:, built as a dam across the previous route of the river. Levels were maintained by the flow of the small
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alongside a tidal waterway which maintains a 'constant' level, despite the changing tides.
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shoreline. These were floating docks, with access through a number of tidal basins and
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Where the dock is lower than the tide, other forms of lock gate must be used, such as
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171:. Entrance to the harbour was now gained through an entrance basin, at what is now
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73:, at least, although in many dock systems the entrance is more complex than this.
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is a partially tidal dock. They need have no gate, but as the tide ebbs a raised
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away from its previous route through the harbour and into a new channel at the
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in
Liverpool, one of the most developed Victorian dock and warehouse complexes
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254:, station was constructed. Liverpool's northern docks were served by one at
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At the most basic level, a floating dock is isolated from tidal water by a
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is tightly controlled by the duty lock-keeper as every tide is different.
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thus interfering with the wharf-side level of every ship in the basin.
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One of the first large fully floating docks was that of
Bristol's
250:. Where there was no such river source, a mechanical pumping, or
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sufficiently to give them a clear passage over the raised sill.
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352:. Proudman Oceanographic Laboratory. Report Number 56.
27:For floating structure used as a repair dock, see
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147:limited the number of ships passing through it.
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308:who made many innovations in floating docks
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426:. Bristol: Redcliffe Press. p. 9.
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106:In 1715 the first commercial wet dock,
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14:
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187:which still flowed into the harbour.
163:. This involved the diversion of the
258:and one on the opposite side of the
422:Malpass, Peter; King, Andy (2009).
366:. Liverpool Museums. Archived from
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364:"Trading Places: Old Dock History"
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1:
345:Woodworth, Philip L. (1999).
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159:, built in 1809 to a plan by
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77:Development and early docks
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424:Bristol's Floating Harbour
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26:
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389:Parsons, Edward (1835).
29:Dry dock § Floating
450:Malpass & King 2009
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94:The first wet dock was
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96:Howland Great Wet Dock
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205:Sandon Half Tide Dock
199:Liverpool's floating
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165:River Avon (Bristol)
102:Liverpool (Old Dock)
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234:impounding station
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90:Howland's Wet Dock
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433:978-1-906593-28-5
203:, fronted by the
16:(Redirected from
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469:Docks (maritime)
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452:, pp. 26–27
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370:on 24 March 2008
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173:Cumberland Basin
157:Floating Harbour
51:floating harbour
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142:In 1775 Hull's
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256:Huskisson Dock
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201:Huskisson Dock
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161:William Jessop
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123:half tide dock
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18:Impounded dock
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230:Pumps within
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47:floating dock
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405:. Retrieved
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372:. Retrieved
368:the original
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212:River Mersey
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407:27 February
374:22 February
290:Branch dock
248:River Frome
185:River Frome
116:ebbing tide
39:Albert Dock
391:"IX "Hull
313:References
252:impounding
240:lock gates
222:Impounding
393:continued
278:Bow Locks
274:Bow Locks
270:Bow Locks
191:Liverpool
108:Liverpool
71:lock gate
65:Operation
463:Category
327:caissons
284:See also
144:Old Dock
112:Old Dock
55:wet dock
169:New Cut
151:Bristol
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260:Mersey
82:London
350:(PDF)
57:is a
428:ISBN
409:2013
376:2013
262:for
181:weir
138:Hull
131:weir
127:sill
59:dock
129:or
110:'s
53:or
465::
442:^
397:.
395:""
304:,
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121:A
49:,
45:A
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411:.
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31:.
20:)
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