Friday, October 28, 2011

MV Beaumagic

Dutch general cargo ship Beaumagic unloading in Seaham harbour early this afternoon.

Wednesday, October 26, 2011

HMS Ledbury visiting Newcastle 23/10/2011

 The Hunt class minesweeper HMS Ledbury (M30) moored on the quayside at Newcastle during a visit on 23rd. October 2011 ........
.......... sharing the quayside with the traditional Sunday market.

The ship has a glass reinforced plastic hull - similar to the pre-formed hulls you can buy for model ships. The virtue of this form of hull construction for a minesweeper is that it's non-magnetic - the downside was the enormous development cost; producing GRP hulls on this scale made Hunt class minesweepers the most expensive ships ever built for the Royal Navy on a  cost-per-metre basis.

Thursday, October 13, 2011

Dry Dock and Marine Fouling

Keeping ships and boats free of marine fouling - encrustations of marine organisms on the underwater hull - has been a problem ever since people began making voyages in boats that were too big to simply drag out of the water every day. Careening was the solution for small sailing ships, when they could be run up on the shore on a high tide. When they were left high and dry hull maintainance was possible between the tides. As ships grew larger this became more difficult, and sheathing the hull in copper - toxic to marine life - could help keep toredo worm at bay and reduce encrustations of barnacles and other organisms that created drag on a ship's hull. The problem became more acute with the advent of the iron steam ships that had to carry fuel rather than rely on the wind, so that drag on the hull increased coal consumption as well as slowing the ship down - and for warships in battle speed was of the essence. Anti-fouling paints - loaded with toxic tin and copper compounds - came to the rescue but needed to be regularly reapplied - and that couldn't be done by beaching 12,000 ton battleships and working between the tides. So the development of ever-larger dry docks was a key requirement for commercial shipping and navies once the age of iron steamships arrived. The Holzapfel brothers must have done very well out of their Anticorrosive and Antifouling compositions, used by the Royal Navy and great shipping lines like Cunard.

Here’s the 15,000 ton Victorian battleship HMS Magnificent, one of the Majestic class, newly completed in December 1895 and ready for commission, about to leave the dry dock at Chatham which has almost refilled with water. When the lock gates open she’ll pass out into the River Medway and sail to Devonport, to become senior ship in the Western Division of the Channel Squadron – and no doubt begin to acquire an encrustation of marine life on the bottom of her hull. She must have looked as magnificent as her name suggests, with buff funnels, white upperworks, black hull and white boot-topping above her hull bottom, protected by red antifouling paint. She survived in various guises until 1921 and you can read her service history here.

HMS Empress of India in dry dock in Chatham in December 1895. The lock gates have been shut, the dock has been drained and the ship is braced against the dockside with massive timbers while her hull is examined. At this time naval dockyards suffered from a serious shortage of dry docks to accommodate the rapidly expanding fleet of increasingly large and powerful battleships – Empress of India had seven sister ships and the even bigger Majestic class had eight. Notice the Admiral’s stern walk – still an ornate feature of capital ships at this time. She was deliberately expended as a practice target in Lyme Bay in 1913 and today is a popular wreck for recreational divers to explore.

HMS Nile, sister ship of HMS Trafalgar described in an earlier post, in dry dock in Malta. She was a 12,000 ton battleship completed in 1890 and, at the time of this photograph in 1895, part of the Mediterranean Fleet. Down in the bottom of the dock shipyard workers are inspecting her hull. Notice her ram bow - equipment for a form of naval warfare that dates back to classical antiquity that could still to prove useful against the new-fangled submarine that would threaten surface fleets: HMS Dreadnought, the epitome of the big-gun ship, rammed a sank the U-29 in 1915, so becoming the only battleship ever to sink a submarine. Ironically, the present HMS Dreadnought was Britain's first nuclear-powered submarine.
HMS Nile was broken up in 1912.

Images of ships here are from an old and tattered copy of the 1896 edition of The Army and Navy Illustrated that I found in an antiquarian bookshop.