Modelling Traffic Patterns

[Graeme Dunbar]

Somethink else to bear in mind is tides. I believe in parts of Wales the difference between high and low tide can be rather large (as much as 3 m?). If it is going to take a day or two to offload then gang planks will need to cope with them. I would guess a pontoon might be necessary and space in a sheltered harbour in hilly/mountainous country is going to be at a premium.

My personal choice would be some sort of basket/crane contrivance. There are instances of novel and canny mechanisms in the area and era. I remember visiting the site of this when my parents lived in the area:
http://www.ceredigion.gov.uk/utilities/action/act_download.cfm?mediaid=17537&langtoken=eng
I think the remains of the winding gear were still visible.

[tedp]

Many small harbours dry out at low tide, so the height difference may be much less even with a tidal range of several metres. The height of a quay wall would allow for spring tides not overflowing the quay. In addition an empty ship rides high and a loaded one has a low freeboard. If a whip on a yardarm is used however cargo work can continue at all states of the tide. Loading operations over a gangway are no problem as long as you use a long gangway so the angle isn't too acute. In practice all kinds of solutions would be found - there never is a cookbook approach in seafaring. Improvisation is the word.  ;)

[rhobat bryn]

In addition, the jetty at Aberdovey was built in 1887 so that ships could load and unload regardless of the tides.  The length of the jetty was 370 ft.

[rhobat bryn]

I've just returned from my visit to the National Waterfront Museum at Swansea with a few additional facts.  There is a large scale model there of a Western Ocean Yacht, i.e. three-masted schooner of Porthmadog fame, and it clearly shows that there was a winch next to the main hold at midships attached to a block and tackle.  The block and tackle were also attached to a beam (I need to improve my naval terminology) which could be swung from the centre line across the ship's edge onto the dockside, very similar, if not the same, to the whipping described by Ted.  Interestingly there was also an old photograph showing planks running from the dockside onto the deck with men standing holding wooden wheelbarrows.  I surmise from this that, in these particular circumstances, the slates would have been wheelbarrowed onto the deck by the hold and then winched down using the block and tackle, the reason being that it would have been quicker to do it this way rather than using the hoist for each batch of slates, and there would have plenty of cheap labour around to do the work.  I was also able to ascertain that certain loads were carried in bulk on these ships, marble from Italy for one.  I suspect that the marble would have been unloaded using caskets similar to those for coal though I haven't been able to ascertain this for sure.

Just as importantly, I have been given the name of the Curator of the Museum, whose speciality is maritime history, so that I can contact him regarding my enquiries when he returns from holiday.  So watch this space for more five-anorak quality detail regarding the loading and unlaoding of freight at Welsh ports.  A pub quiz based on this thread will be held in December 2012 to test your knowledge of this crucial subject.

[pilotfriend]

Is this the same quizz when we shall be asked about pug bashes? ;D

[rhobat bryn]

Is this the same quizz when we shall be asked about pug bashes? ;D

I'm afraid I can't comment on that as the trial is still pending in the High Court.   :)

Happy New Year, John.

[tedp]

Rhobat: the beam you refer to is called a 'derrick' in steamers. In sailing ships it may have been called a 'boom' - this is the term used for the spar at the bottom of a schooner's fore-and-aft sails. I expect this might have been used for the same purpose. In a steamship they put one derrick over the quay and another over the hold, with guy ropes to prevent them from swinging. The runners on the derricks were connected so you could haul a load from the quay to the hold by winching up on one, then taking over on the other runner. This was a very quick and expert operation.

I'm looking forward to your quiz. Put in one or two questions about pugbashes to satisfy John!