BREAKWATER EXTENSION.

Taranaki Daily News, 11 June 1921, Page 4

BREAKWATER EXTENSION.

CHANGE IN THE PLANS. RUBBLE WALL SCHEME. MORE RAPID WORK. The New Plymouth Harbor Board intends to make application to the Mu-* rlne Department for the approval of a proposal to construct the breakwater extension by a rubble wall instead of following the present method of concrete blocks. This decision was come to at yesterday’s meeting, following the consideration of reports from the board’s engineers. At the May meeting the resident engineer (Mr. Baxter Lowson) submitted estimates showing the comparative costs of the two’methods, and the board decided to secure the opinion of the consulting engineer (Mr. J. Blair Mason). The report from the latter came to hand at yesterday’s meeting and expressed approval of the resident engineer’s suggestion. The resident engineer’s report estimated that it would take three and a half years to complete the 800 feet of extension, following the existing construction, and the cost would be £69,600, or £B7 per lineal foot. The tension in rubble, with the wall eight feet higher than at present would take about two years to complete, at a total cost of £45.500, or £56 5s per lineal foot.

Following this came the consulting engineer’s opinions, of which a summary is given below: “This construction is on the lines advocated by Messrs. Carruthers and Blackett, Government marine engineers, who reported thereon in 1875. In 1879 Sir John Coode visited New Plymouth and approved generally} 1 of Messrs. Oarruthere’ plans, with modifications in the profile, to which Mr, Lowson’s design closely corresponds. Coode expected to obtain the stone from Paritutu, but owing to information supplied by the then resident engineer (tar, . Rees), to the effect that only one-tenth of the stone quarried at Paritutu would exceed 30cwt. in weight, he had no, other course but to alter the mode of construction by the substitution of concrete work for rubble stone. The plans* submitted to the Marine Department in, June, 1919, and approved, were shown of similar design to that of Coode’s, and for the same reason—viz., that no stone was in sight at the Fishing Rock quarry, upon which at that time the board was dependent for stone supply, pending the opening out and making available of Moturoa Island quarries. “The supply of massive and heavy stone, both at Moturoa Island and Paritutu, is now practically assured, and makes the construction under review} worthy of favorable consideration. . , The stone at Paritutu, as revealed by, . the recent blast, is highly suitable for the work, and can be had in blocks of any size up to 30 tons weight, capable, without disintegration, of standing the pounding of the seas. “We have discussed with Mr. Lows an details of the manner and method of depositing the stone. It is proposed as heretofore to continue the barging of the stone as long as there is water enough to float the barges. In this connection it will be found that two barges can be kept going from the Paritutu quarry, and enable the slopes to be raised ahead of the heavy stone to be tipped from the wagons. It is urged that another barge be obtained to assist the Thomas King, and thus hasten the completion of the 800 fe£t authorised. “The elimination of the concrete block and monolithic work means a great saving in time, in that there need be no delay as in former years ’in the tipping of stone, which operations can be continued without interruption, save when the approach along the existing breakwater is washed by the sea. With the atone supply now available, and with the assistance of another barge to work in conjunction with the Thomae King, Mr. Lowson’s estimate of two years should be realised. We therefor® advise the board to approve of the design in rubble, and that a copy of the plan of construction be forwarded to the Marine Department for the approval of the Governor-in-Oounc.il."

In receiving the report, the board decided, on the motion of Messrs. C. E. Bellringer and D. J. Hughes, to make ■application to the Marine Department for approval of the change in plans.