UIM - Hydro rule changes

[Tom Cronk]

Materials

Fast Freddie
What are the other aramid materials beside kevlar they
are talking about in the rule book.???????????
Tom

[Al Peffley]

Other Arimid Materials & Composite Combinations for Boats

Tom,

Kevlar and Kevlar 49 are duPont trade names for an arimid polyamide fiber type with an aromatic ring structure that can be formed into a strong and water-resistant fiber. There are other international chemical companies that produce this type of arimid fiber material under different trade names -- some of them are using new, high-tech nanostructure processes with highly aligned carbon fiber molecules interlaced within the arimid fiber (I think this new expensive hybrid fiber material is called a "carbon fiber arimid".) The other arimid fibers are used in a variety of body armor and protective suit applications for first reponders and the military. Someone in the UIM realizes that these other Kevlar-like and new nanotechnology hybrid fibers exist. These arimid materials are made from engineered "organic" compounds that have some things in common with silk and spider web materials in nature.

Nomex is another arimid type of material used in composite stuctures to improve strength without adding a lot of weight like a layer of metal might add (such as titanium). Normally Nomex is produced in a honeycomb-like sheet that bonds well to fiber-weave blankets, using epoxy resins as the "plastic"-hardening matrix component, with other organic fibers like carbon-graphite and/or Kevlar making up the blanket layers. The combination of hybrid Kevlar 49 and Carbon Graphite (Gr) bi-directional textile weave material that are laid-up with a thin Nomex core makes a crush-resistant sandwich that is hard to beat for being light weight, somewhat elastic on impact, and strong; this is only true in boat building as long as the epoxy (Ep) resin fully seals the sandwich of disimilar materials from water.

E-glass panels and an aluminum honeycomb sandwich core integrated with epoxy resin matrix is more structurally sound for boat structure panels if it gets penetrated and exposed to water, but these panels have a lower tensile strength than the GrEp-Kevlar and Nomex composite sandwich structure. Therefore, never use E-glass/Al panels for armor protection applications and don't use GrEp-Nomex panels for boat bottom structure panel applications (unless you are willing to replace the whole bottom panel if the GrEp surface is penetrated and the swollen core/carbon fiber is damaged since its tensile strength has been compromised by water penetration and delamination.) You can bond all of these materials with the right thickness of a good plywood to form a very light and strong complete boat hull -- the weakest combinations will give with excessive pounding and foreign object damage strikes under operation (including other boats!) Nate Brown is an expert in this field; I am only a "student" from my past aerospace programs experience of this interesting, and changing (using nanotechnology), materials field...

Hope all of this this helped you some. Fiberlay sold the Graphite Carbon/Kevlar weave fabric we have been using on racing boats and racing sport cars here in the Northwest. I have not purchased any of the Gr/Kevlar 49 bi-directional weave material for some time now, but I am sure there must be other industrial supplier sources for it.

Al Peffley
15-R/R-25