Was the working shipyard dock's bottom flat or sloped? (18th century)

[modeller_masa]

 

I have a question about 18th century shipyard docks. According to the video's beginning, the shipyard's bottom is flat and wide. The keel is on the wooden logs like a railway. I'm curious how did 18th century sailing ships, like the HMS Alert, get balance when she was launched.

 

( Source : https://www.rmg.co.uk/collections/objects/rmgc-object-68861 )

 

 

I researched some contemporary dry dock dioramas, and they shows several characteristics of dry docks in 18th century.

 

1) Some dry docks had water gates, so the gates are opened when the ships were ready. It is identical to modern shipyard.

2) Some dry docks had sloped bottom. As a result, the ships were on uneven ground.

3) The outside of the dry docks were connected to 'railway'. It is really amazing how the ships were safely balanced when she was moving on the wooden logs and railway before ceremonial launching day.

 

( Source : https://www.rmg.co.uk/collections/objects/rmgc-object-68110 )

 

4) In the Chatham dockyard diorama, all the dry docks had flat and solid wooden bottoms. It is very similar to the modern shipyards.

 

It looks like magic that completed ships on the wooden log rails were smoothly launched without any rollover accidents.

 

Summary

- In the 18th century, were all dry docks for large sailing ships flat?

- Were the wooden logs sufficient to launch the big sailing ships without water? Did workers replace the wooden logs with rail before launching?

- Why didn't dockyard place completed wooden rails when she was laid down?

- Were there any launching accidents in the century? I remember the HMS Formidable's case.

 

 

I think this question is a big chunk to digest at once. Could you recommend any reference books or guides to explain launching the big sailing ships?

Edited May 20 by modeller_masa

[druxey]

Even dry docks would need a slight slope for drainage, would they not?

[modeller_masa]

8 minutes ago, druxey said:

a slight slope for drainage

It makes sense, because drydocks in the 18th century didn't have electric water pumps.

However, the slopes are not sufficient for launching ships by gravity. Even roman roads had drainage slopes.

[realworkingsailor]

It’s important to distinguish the difference between a build ways and a drydock. A build way is typically sloped to the water’s edge, and while the ship is built, it doesn’t actually rest on the slipway until just before launching.
 

A drydock is constructed below the level of the water, and does have a flat bottom. It might have some sloped drainage towards the centerline, or to wherever the drain valves are located. Where pumps are not available, drydocks can make use of natural topography to fill and empty. For example, by locating the dock some ways up a river, after closing the gate, the water can be drained to sea level (helps also to do the draining when the sea is at low tide). There is a drydock in Port Weller, Ontario, that is located above the first lock in the Welland canal. It doesn’t use pumps at all. The water is allowed to drain down the 40’ drop into Lake Ontario. 

 

Things haven’t changed too drastically over time so some pre-modern ship launching techniques are similar. Prior to  launching, the slipways (usually a pair of flat beams laid astride the keel (you can see these in the picture of the shipyard model you posted), are well greased with tallow or other lubricants. A pair of special launch cradles are constructed fore and aft. These cradles will bear the weight and balance of the ship when it comes time for the launching. These will slide down the slipway, but are held static by a series of chocks and braces. Once the launch cradles are built and braced in position, the ship is then slowly lowered from its build staging (usually by knocking out the keel blocks) onto to the launch cradles. Any remaining staging is removed, and when the time comes for launching, the chocks are knocked out and the cradles (with the ship) slide down the ways into the water. Typically hawsers or anchor cables are used to arrest the movement of the ship once waterborne.

 

Hope that helps.
 

Andy

Edited May 20 by realworkingsailor

[modeller_masa]

Thank you for the detailed explanations, Andy. The launch procedure is more complex than I thought. It is really interesting that dock workers remove stable wooden logs and insert slipways one by one, like a jenga game. Also, the method of draining water using terrain is really clever.

 

Because of the special equipment, such as slipways and launch cradles, I'm not ready to build launching ceremony dioramas. I'll keep it on my bucket list and collect more data for future building... Thanks so much!

[allanyed]

Google Buckler's Hard then go to images.   There are a number of photos where you see the slope on the area of the old slipways into the Beaulieu and even the main road through the village slopes down to the river.

 

Allan

[Mark P]

Good Evening Masa;

 

In the Eighteenth century most ships of any size were built or repaired in a dry dock. An existing ship would be floated in on a high tide, and as the water receded, the hull would be propped up with a large number of shores, whilst her keel would settle on a line of timber blocks. The base of the dock sloped towards the river, both to allow the water to drain away thoroughly, and to facilitate launching on a slipway. Once the dock was empty, a pair of gates would be shut across the entrance to keep the water out. In earlier periods, the dock would be closed with a bank of clay and stones. 

 

The floor of the dock was made of stout timbers, called the 'ways' which were set in like railway sleepers. The blocks to support the keel, and the shores, would be nailed to these ways to prevent them moving.

 

A new built ship could be launched by opening the gates and allowing the dock to fill with water; this was best done with extra high tides. On the other hand, if there was no high tide soon, the ship could be launched  down the ways; this was done by setting down timbers like a railway track, called a slipway, running into the water. The ship was fitted with launching cradles at the bow and stern, which sat on the slipway, and the blocks under the keel were knocked away. The ways were well-greased. Sometimes the ship would slide down the ways easily, other times she needed a good pull to get her moving. 

 

The book 'Building the Wooden Fighting Ship', by James Dodds and James Moore, describes the build process in detail, with a large number of hand-drawn, good quality illustrations, and also covers the launch. There are several models of ship on the ways ready to launch, including the well-known model of the Bellona, and the Victory of 1765. 

 

All the best,

 

Mark P

 

 

Edited May 20 by Mark P

[mtaylor]

Mark,

Your reference book recommendation is excellent and I was about to recommend it .

[Roger Pellett]

In areas with large tidal ranges there were special dry docks used for building ships.  

 

In 1940 Great Britain contracted with the now famous “7 Companies” that built Hoover Dam to build 60 badly needed, large for the time, merchant steamships in the USA.  Since American Yards were busy, the deal included building two new shipyards; one on San Francisco Bay and another on the East Coast in Maine.  Conditions in San Francisco Bay, including tidal range were such that conventional sloped launch ways were quickly constructed.

 

The large tidal range in Maine required construction of dry docks.  The need to blast these docks out of Maine’s granite delayed the construction of these East Coast  Ocean Class ships by several months.

 

Ships on the Great Lakes built prior to the 1000 footers were traditionally launched sideways.  The smaller Navy Combatants being built by Fincarii Marine in Wisconsin still are.  The 1000 footers were built in a dry dock.

 

Roger

 

[modeller_masa]

7 hours ago, allanyed said:

Buckler's Hard

The diorama and a beautiful painting are really nice examples, Allan.

 

6 hours ago, Mark P said:

Building the Wooden Fighting Ship

I turned my chair 180 degrees and picked up the book.  The step by step illustrations are really impressive. Thanks for recommendations, Mark P.

 

I can't imagine how the Great Britain was launched sideways.

[allanyed]

 I worked in two different barge and river boat yards in Pennsylvania and Kentucky and in both we launched everything sideways.   We did have one disaster when one of the four restraining systems was not released to allow the vessel to slide down the ramp so it turned and went off the greased rails.   What a mess that was.   

Allan

Edited May 21 by allanyed

[Roger Pellett]

The famous Great Lakes Steamship Edmund Fitzgerald that was over 600ft in length was launched sideways.  So were the rest of the 600ft+  Great Lakes vessels built in the American yards in the 1950’s.

 

Drydocking a ship usually requires a “docking plan” prepared by a Naval Architect. This shows the arrangement of the supports in the dry dock.  The support structure can be checked by conventional surveying methods before the dock is flooded to receive the vessel.  Any irregularities in the dock floor can be allowed for at this time.

 

I’ll check my copy of the Iron Ship this PM but I believe that Great Britain was built in a specially built dry dock.

 

Roger

[allanyed]

The photo below is the slipways at Hillman Barge and Boat in Brownsville, PA where we had the mishap.  This photo was right after a successful launch as the barge and catch boat can be seen on the right.   Googling photos of the yard like the one I found below brought back some really nice memories.   

Allan

[Roger Pellett]

Dravo’s Neville Island yard used much the same setup.  Of course, the width of the yard’s waterfront could a bottleneck in the mass production of these simple vessels as it restricted the number of launch ways that could be built.

 

To overcome this Dravo had a setup where barges and towboats moved across the yard sequentially until the completed vessel reached the launch ways.  I would assume that other River yards used the same system.

 

I always thought that I would have liked to work at Dravo’s shipyard, but instead they wanted me at their Pipe Fabrication Division.  In the end, I was lucky.  The shipyard closed in the late 1980’s but the Pipe Fabrication continued into the early 1990’s.  By that time I had a new job here in Duluth.  I did see the yard side launch a barge- Big Splash!

 

Roger

[amateur]

My favorit side launch on you tube: 

You can find lots more, many clickbaited by a  ‘went horribly wrong’-title, but actually this is quite standard at some larger inland builders: no space to do it ‘stern first’.

jan

 

Edited May 25 by amateur