Engineering Wonders of the World
Volume I

74 ENGINEERING WONDERS OF THE WORLD. ing of the ground and the laying of the ways for the launching of the ship. There is no tide on the Baikal, and conse- quently this undertaking presented many diffi- culties, and necessitated a foundation for the permanent ways being carried Building- about 120 feet into the lake, the „ , . At that distance out there was Launching Ways sufficient depth of water on the way ends to ensure the ves- sel being launched without any risk of acci- dent. The extended ways were supported on “ BAIKAL ” ABOUT TO START. ' (Fi'J- 10.) piles driven deep down into the bottom of the lake. Each tier of piles was cut off to the required distance below the water, the depth increasing as they extended out into the lake. Cross baulks were then fastened athwart each tier, and to these the permanent ways were securely fastened. The piling was all done during the winter months, while the lake was frozen, as the strong ice formed a good foun- “ Freezings dation for the pile-driver to out.” work on ; and the piles were cut off to their required height below ths surface by the process of “ freezing- out.” The ice was allowed, however, to attain its maximum thickness before this work was commenced. A short description of this freezing-out pro- cess may here be interesting. The ice at this time was about three feet thick. In it a square hole was cut round the head of each pile to a depth of, say, 34 inches, leaving two inches of ice at the bottom of the hole. This was sufficiently strong to prevent any water forcing its way through. The hole was made wide enough to allow the now pro- jecting head of the pile to be cut off level with the remaining two inches of ice. As the ice is cut down the water below freezes, and the hole is made deeper and deeper until the pile has been shortened to its required depth below the surface. Frequently too little. ice was left at the bottom of the cutting, and the water found its way through and filled up the aperture, which in turn soon became frozen again, and the freezing- out had to be repeated. Be- fore the cutting down of the piles at the extreme outer end had been completed, the ice began to break up, and caused the abandonment of the process. The work was, however, finished by divers, who also laid the cross baulks and fastened the ways on to them. Fig. 3 shows freezing-out in progress. Every winter it gives employment to a large number of men on Lake Baikal. There are several small steamers on the lake—at that season of the year, of course, frozen up—and by means of freezing-out round their sides and underneath the bottom the vessels are practically dry-docked, cleaned, and painted. The securing of the ways underneath the water caused a lot of trouble. As they were of large displacement, their buoyancy made it