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Naturalfibers

Naturalfibershavenowalmostcompletelybeenreplacedby
synthetics,butthemostcommonlyusedwerehemp,manilla,

cotton,andsisal.Itisstillpossibletocomeacrossropemade
ofhemp,whichuptoa fewyearsagowasthebestmaterial
availableforrope. The advantagesofthis material are its
tensile strength and an excellent resistance to wear and
atmospheric agents, which is even better than that of
synthetic fibers. Its disadvantages are that it is heavy
(especiallywhenwet)andisnotveryelastic,butparticularly
thatit rotseasilyandhastobestoredcarefully.

Syntheticfibers

Astheirnamesuggests,thesefibersarecompoundedbyman

fromoilorcoalderivatives.Theyareallshiny,non-absorbent,

donotrot, and have lowmelting points. The production

processesinvolvedmakeit possibletoimprovefeaturessuch

asthefineness,strength,andelasticity.Ingeneral,anincrease

inthestrengthofa ropecorrespondswitha decreaseinits

flexibility.Greaterfinenessisassociatedwithgreaterstrength

andflexibilitybutalsowithlessabrasionresistance.Themost

commonfibersarepolypropylene,polyamide,andpolyester,

but to complete the picture, we have also included

polyethyleneandaramid.

Polypropylenefibers

(commonlyknownasolefin)

Thesearewidelyusedin commercialsailing,astheycombine

lowcostwithexcellentmechanicalqualitiesand abrasion

resistance.Theyalsohaveveryhighresistancetoatmospheric

agents,light.andthehydrocarbonsthatarealwayspresenton

thesurfacesofcommercialports.Thisistheonlyfiberthat

floatswell,soitismostsuitableforuseinwaterskiingtow

ropes,rescue lines,andformooring largeships. Itis not

commonlyusedincompetitivesailing,possiblybecauseitis

cheaperthanothertypesofrope.

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