FIBRE FOR ROPES

Wanganui Chronicle, Volume 74, Issue 115, 18 May 1931, Page 11

FIBRE FOR ROPES

SUCCESSFUL TESTS MADE. NEW ZEALAND FLAX. *ln order to test the suitability of fibre made from New Zealand flax for the purposes of marine cordage, the Department of Scientific and Industrial Research some time ago forwarded a number of graded samples to the Jm perial Institute and to the Admiralty, in order that tests might be carried outunder proper condition!*, and that a comparison could bo made between the relative values of New Zealand phorm ium and its competitor fibres, sisal,

hemp, and Manila. Promising results were obtained with ropes made from New Zealand hemp, which, proved of equal durability to the best sisal rope. These ropes, however, had initial tensile strengths lower than the standard demanded by the speeifi cation of Government departments, although that composed of tho high point fair grade, which represents the bulk of the commercial output from New Zealand, was almost up to the standard. Exposed to Sea Water.

The ropes were tested by actual exposure to the action of sea water. They were fixed in wooden crates to Southend Pier, in a position that would ensure that during each tide they were completely submerged for a period, and completely uncovered for a period. During the time they were exposed sample ropes were taken out at monthly intervals, and tested for breaking strain. The breaking strains of the various ropes before immersion were as follow: Sisal, 93871 b to 11,2531 b; Manila, 9263. lb; Russian hemp, 92101 b; Indian hemp, 83581 b; New Zealand hemp, 74001 b for fair, to 81031 b for high point fair. Good fair had a breaking strain of 78621 b.

The four New Zealand ropes used in the trials were all of lower initial strength than tho Manila and tho four sisal ropes. During tho first two months of exposure to sea water they suffered a smaller loss than the sisal rope, and more resembled the Manila rope in behaviour. During the third and fourth months, however, tho phormium ropes sustained a large loss, so that at the end of four months’ exposure the percentage loss undergone by the phormium ropes was nearly equal to that of t he fisal, and slightly greater than that of the Manila rope. The Admiralty tests laigely confirmed those coL.iucted by ihu Imperial Institute. lr thr Armiralty trials 3-inch ropes juu'.lo from three graces of fibre, namely “B” fine, g'>>4 fair, and high point fair, were found to have initial strengths distinctly h’gher than those of tho four ropes made iioin New eZaland hemp, and tested at the Imperial Institute, but ihej did net quite attain the standard demanded tv Government departments for 3-inch Manila ropes. In the sea exposure tests the New Zealand grades are stated to compare closely with sisal, but are not up to the standard of Manila. Each grade, so far as its capacity to resist the action of sea water is concerned, is regarded as fairly satisfactory. A sum-! mary of the Admiralty results indi-

(1) That the best of the New Zea land grades is high point fair, and with this grade further trials are now pro ci eding in the Naval Service. (2) The B grade and good fair cannot be regarded as suitable for the manufacture of marine cordage in view of their low .initial tensile strength. (3) Phormium fibre possesses much the same colour as Manila, but is rather coarser. (4) All

grades are capable of withstanding th action of sea water over prolonge periods, though hardly up to the stam ard of Manila. (5) When immersed i

sea water, all the New eZaland grades absorb water »t. a much greater rate than Manila, pnd sink more rapidly, but are rather better in this respect than sisal. Moreover, the New Zealand phormium ropes swell more, and remained in a swollen condition when subsequently dried. In general, the result of these, trials conti'-ms the impression that ropes made from New Zealand phormium fibre can

fulfil a useful function in the inanufac turn of marine cordage, and no doubl is cntoitßii’.ed that when further atten

tion is <3. voted to the breeding of suit able strains, ropes made from fibre secured from such will give much more