Yesterday I completed the basic functionality of the annotation system for my image viewer, using the Google Maps' marker feature. Each marker is shown as a red icon overlaid on the image. If the marker is clicked, an info window (looks like a comic book speech balloon) will open, displaying the annotation text.
So far it is possible to create new markers and view the existing ones, but they can not yet be moved, edited or deleted. This will obviously have to be implemented. Also, I would like to change the default marker icons used by the Google Maps API. Finally, the shadows that the API uses behind the markers and info windows seem unnecessary and potentially confusing, so I may remove them.
The image viewer saves and loads annotations using AJAX, so reloading the page is not necessary. The current implementation stores annotations as an XML file in the complex obs directory, but this can be changed fairly easily.
HMS Habakkuk
Though reading about my summer of code project must be quite captivating, let's move on to something even more interesting.
Project Habakkuk was a British plan to construct the world's largest aircraft carrier during WWII. This project was the brainchild of English journalist/spy/inventor/mad scientist Geoffrey Pyke, and was based on his most famous invention: Pykrete.
Pykrete is a composite material made by mixing sawdust or wood pulp with water, and then freezing it. The optimal mix is supposedly 14% sawdust and 86% ice (by weight). The properties of this material are quite impressive: It is easy and cheap to make, incredibly tough (comparable to concrete) and has a very slow melting rate.
Project Habakkuk, if successful, would have involved creating a huge, unsinkable floating island out of pykrete, probably in the Canadian winter. The top side would have been leveled to make room for one or more airstrips, and the center hollowed out for storage of 150 twin-engined bombers or fighters. Several anti-air installations would have been added, and the ship may have been reinforced with steel.
The final design called for a displacement of 2.2 million tons (the American Nimitz-class supercarriers have a displacement of 80,000-100,000 tons) and a length of more than 600 meters (twice that of the Nimitz-class, and enough for an airstrip suitable for the heavy bombers of the time). Steam turbogenerators would have supplied 26 electric motors mounted on external nacelles, similar to the way propellers are mounted on an airship.
A possible design for the HMS Habakkuk, shown next to an Iowa-class battleship and a Nimitz-class supercarrier.HMS Habakkuk would probably have been impervious to submarine attack, and highly resistant to enemy bombing raids. Refrigeration plants would probably have been added to prevent melting, although the slow melting rate of pykrete may have enabled the ship to last for a year even without these.
Geoffrey Pyke presented his idea to British Admiral Lord Mountbatten, a favorite of Winston Churchill, and the uncle of Prince Philip. Mountbatten in turn presented the project to Churchill in 1942. Several tests were made to optimize the properties of pykrete, and a scale model was constructed in Canada.
At the Quebec Conference of 1943, Lord Mountbatten made a demonstration for a group of admirals and generals along with Winston Churchill and Franklin D. Roosevelt. Mountbatten brought a block of normal ice and a block of pykrete, to demonstrate the strength of the new material. He placed the blocks on the floor, drew his service pistol and fired at the ice block, which shattered. He then fired at the pykrete. The bullet ricocheted off the block, grazed the leg of US Admiral Ernest King, and ended up in the wall. The Admiral was highly impressed by Mountbatten's unorthodox demonstration.
Project Habakkuk began to lose priority later that year, and it quickly became apparent that the technical difficulties and the enormous resources required were too high.
It took three hot summers to completely melt the Canadan prototype.
