Tuesday, May 12, 2009

M. R. Dux



Some of you may be familiar with Dynex Dux 75, a heat set Dyneema line made by a company in Iceland named Hampidjan. It's been in the sailing market for a little while now - primarily seeing use in high tech halyards and sheets on boats like Farr 40s and the like. We've offered it in 7, 9 and 11mm in the past but this year we have it available in 5mm as well.

What's so special about Dynex Dux? Dynex is made from SK-75 Dyneema that is then heat set which is a process where the line is heated up and then stretched out on rollers and then cooled down while still stretched out. This process significantly increases the breaking strength (20-43% stronger than non heat set SK-75) and minimizes creep.

If you have never seen Dynex Dux it looks very similar to the other Dyneema products we offer - it's gray and it's a 12 strand single braid. When you feel it though the difference of the heat set is immediately apparent. It's very stiff - it holds it's shape unless you give it a firm bend in which case it tends to hold that bend. This is due to the heat setting process - all of the fibers are lined up and compacted together.

Hampidjan basically makes supplies for commercial fishing and other deep water applications. The sizes of Dynex Dux that we carry are the start of the size range they offer - the Dux for instance is available up to 51mm (about 2 inches) with a breaking strength of 242 tons. 51mm is actually a fairly small line for these guys who make other Dynex SK-75 products for uses such as marine geological seismic surveys and measure all of their breaking loads in tons.

So in short these guys know what they're doing when it comes to making strong lines built to hold up to a lot more than a bunch of sailors can throw at it. Below is a comparison of the breaking strengths of Dynex Dux to the other Dyneema SK-75 lines we carry.

Diameter
Tensile Strength
Dynex Dux 75Amsteel BlueYale Ultrex 12
3/16"10,4945,4005,250
9/32"16,41113,700(5/16")13,500(5/16")
3/8"26,52719,60020,000


As you can see the Dynex Dux is significantly stronger than traditional SK-75 Dyneema. It's lower creep makes it a viable solution for upwind halyards, backstays or runners. The addition of the 5mm size makes these advantages more accessible to smaller boats than previously.

Dynex Dux is a fiber that we're still learning all the uses of. I think over the next year we will offer more of our one design rigging options available in Dynex Dux where it's appropriate. Things like J24 or J22 halyards and maybe Melges 24 main halyards would be a natural use of the newer 5mm size with a cover installed over it. Give us a call if you think you have a use for this fiber on your boat and look for more ideas in the future to take advantage of it's unique properties.

2 comments:

  1. I'm thinking of using this line as a forestay on a J130 with a Karver furler to roll up the genoa. Still waiting for Karver to make a top roller for their size 5 or larger furlers. I currently have the equipment for a gennaker furler on the sprit and will undoubtedly use DUX line for that also. However I wonder if the line is so stiff that it makes it difficult to take down between the racing marks.

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  2. My experience is that after being worked a few times it softens right up. I know of only one vessel that is using it and his results have convinced me. It's a Beneteau 45 and the owner has replaced EVERYTHING with this Dux. Headstay, backstays shrouds halyards upper lifeline, if there's a line on his boat - it's Dux. (except the lower life line - that is just dyneema :-) ) The weight savings alone are incredible.

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