OAMARU HARBOR WORKS.

Evening Star, Issue 3231, 28 June 1873, Page 2

OAMARU HARBOR WORKS.

The following letter by Mr M‘Gregor, C.E., to a gentleman in Napier, sppearsin a local paper:— ~ ~ The Hon. Mathew Queried me to send yon a few particulars regarding the 'breakwater now under constmctionat the port of Oamara, and in compliance with bis wisbe", I beg tb inform you that Hie breakwater, as Fnave designed it, and being carried out successfully so; far, m y * tended to enclose a space of abent »r«*y acres, and forin a commercial harbor raffi* eiently large to accoinniodato vwsels at lotp tide drawing not more than siiteen tb eighteen feet of water, llie wall is tObf 1,200 feet long, and is constructed of Fort: land cement, concrete blocks,' kith rubble pockets (at intervals) under lowwaterlme| The blocks that form the outer basing art moulded on a piece of reclaimed and are allowed to stand for two or three months before"remoring'; these weigb from twentyfive to thirty tons, and when they are hardened, are lifted by a forty-ton steam travelling crane, and deposited in their places in the wall. The concrete blocks over the top of the rubble pockets, in the centre of the wall, are built in site, and weigh .110 tnna. At presentthe wall only stands three feet above high water line, , birii -when rib is run oat its full length, ! intend to build a concrete capping in caissons six or seven feet higher, the rnU width and whol* length ii * the breakwater, in One solid monolithicmatte The work is now advanced seaward abbot 160 feet, and appears to stand the force of the waves without showing the slightest signs of damage, and my confidence m the stability and permanent success of Hie work is increasing as the work progresses, The cost of the work (including the cement, which is imported and specially manufactured to the order of the Harbor Trust) is about L6O per lineal foot forward, but any Similar . work undertaken in the Colony coaid be executed for less than this amount. .We hive had to expend large sums in plant and machinery— Hie steam crane alone costing ts; cause all the -patterns had to oe got up for this unusual class of machinery. With regard to concrete breakwaters the improvement of -New Zealand ports, 'f. am of opinion that they can be built any* where where shingle and sand con be pro* cured readily, and can be made strongenbugh to defy any sea. ..