HARBOUR PROPOSALS.

Hauraki Plains Gazette, Volume XXXIV, Issue 4527, 14 February 1923, Page 1

HARBOUR PROPOSALS.

ENGINEER'S PROPOSALS. FURTHER DETAILS. When making his report to the Thames Harbour Board the engineer (Mr E. F. Adams, C.E.) supplied the following statements as' to cost of dredging, plant, etc.: — DREDGING ESTIMATES. All channels to be 150 ft wide L the bottom, with side slopes allowed for .at 5 to 1 up to 18.00 ft over datum, bottom dredged to 14.00 ft. Slopes from IS.OOiEt. upwards tp foreshore or bed, as may be, protected at slope 2 to 1 with stone and gravel against wave wash. Approach chapnel outside enclosed area contains 33,210yd5’; entrance channel to low wateri spring tides contains 48,050yds ; swinging basin, 920 ft long by 150 ft to 670 ft wide, contains 57,045yd5; channel from low water spring tides tp end contains 102,840yds; mooring basin, 300 ft long by 60ft wide, dredged to 5.00 ft over datum, contains 12,075yd5; total cub l 2 yards, 253,220. Of this 1 the amount of 50,000 cubic yards will be pumped direct into reclamation at 4d pen cubic yard, £833 6s’ 8d ; 120,000 cubic yards will be dredged at 8d per cubic yard, £4OOO ; 84,000 cubic yards will be dredged at 9d per cubic yard, £3150 ; allowance for purchase of plant, £3BOO ; allowance for contingencies,, £877 13s 4d ; total cost of dredging, £12,661. Protection of slopes at 2 to 1,18.00 ft over datum and upwards, 4251 cubic yards at ss, £1062 15s. ESTIMATES OF PLANT. Bucket dredge, ladder type, £6OOO ; three hopper punts, £2400 ; one launch; or steamer, £9OO ; wharf, etc., £7OOO ; rubble walls and plant, £17,600 : dredging and suction cutter plaint, £12,661; protection of dredged slopes, £1062 15s; engineering and general charges', £2700 5s ; interest and sinking fund (first year £60,000 at 7 per cent.), £4200 ; contingencies, £5476 ; total, £60,000. Besides the contingencies of £5476 as shown above there are contingencies allowed for in wall material and dredging, making in all about £BOOO under this head. Provision is . made in each of the works to have a ' suitably designed plant to carry them out. The plant will in each instance pay for, itself in economy of working and leave an asset at the conclusion of the operations. Wharf, etc. —Iron bark piles in place, £1712 8s ; cradles, £305 ; fenders, £4OO ; headstocks, 7280 super ft, stringe”* 18,816 ft, planking 16,500 ft, carlines 1726 ft, bollards' 750 ft, braces 4264 ft.; total, 49,320 super feet. 50,000 super feet at £4’ 10s, £2350 ; ironwork, •41251 b at Bd, £137 10s ; shed, £7OO ; reclamation, 4400' cubic yards at 3s, £660 ; 250 ft line, tram, trucks, lights, and dolphins, £835 -2s ; total, £7OOO.

COST OF DREDGING. Bucket Dredger.—Capital cost of whole plant, £9300. Annual charges, 7 per cent, interest and sinking fund, on same, £651 ; depreciation, 10 per cent., £930 ; repairs and maintenance, £509 ; total, £2090. Cost of Operating.—Fuel on 30 b.h.p 3 gallons’ per hour at 2s 6d, 7s 6d per hour; wages five men, dredge and punts Ils per hour; interest, sinking fund, depreciation, repairs, and maintenance of plant on a 12-hour basis, 12s per hour; .total per hour on a 12hour day, 30s 6d ; at, 90 cubic yards per hour equals 4d pen cubic yard. Suction Cutter Pump.—Capital cost of plant £3BOO, equals 2s 7%d per working hpur of 24 hours 300 days a year. Total annual charges £946 per annum. Wages two men, ss’ pe’ hour, 5s ; fuel, 5 gallons per hour at 2s 6d, 12s 6d (this is on maximum power) ; charges as above 2s 7%d ; add for delays 4%d ; total, 20s 6d per worikng hour. Sixty-seven cubic yards per hour at 15 per. cent, solids equals 3 7d dredging cost per cubh yard. WALL CONSTRUCTION. The summary of the quantities in the rubble wall construction is as follows Walls east of enclosed area (length 2800 ft by Bft wide on top, 50ft wide at base, top at 37..00ft over datum), 29 400 yards; wall south of enclosed area (length 1500 ft by 10ft wide at top by 40ft wide at. base, top 29.00 ft to 26.00 ft over datum), 7830yds ; wall west of enclosed area (length 2600fv by 10ft wide at top by 40ft to 50ft at base, top 26.00 ft. over datum), 20,826yds; wall north of enclosed area (length 1500 ft by 10ft wide at topjiy 40ft wide at base, top 29-00 ft' to 26.00 ft over datum), 8460yds; total quantities, 66,516 cubic yards. 66,516 cubic yards' at an average cost of 3s 8d per cubic yard gives in round figures £12,200 ; allowance for quarry trainway, half share, £2200 : allowance for other tramways and plant in construction bf the rubble walls, £3200 ; total cost of enclosing walls, £17,600.

The average cost of various grades of the material in the walls runs as follows : Dredges material (23,300 at Is 6d), £1747 10 s; material from dumps (23,216 at 2s 6d), £2902 ; rock (20,000 at 7s 6d), £7500 ; total, £12,149 10s. As stated above, in round figures £12,200. Some of the rock will cost as low as 4s per cubic yard in place ; some will cost as much as 12s per cubic yard in place. The sum of £2200 for half share of quarry tram assumes an amicable arrangement between the Board and Borough Council in the development of Waiotahi quarry—the Council’s property.