Dynema Dilemma

[Rappey]

I read an article about the us coastguard testing knots in dyneema. The best knot gave up at only 13% of the breaking load of the dyneema

 

[Lightwave395]

Deleted

 

[gregcope]

I have fitted Dyneema single 12 strand lifelines. I added an outer Dyneema cover to the areas that went through stanchions. I polished the stanchions holes; Firstly with a dremel sander and then with a cloth and polish. They actually seemed fine before I started.

The top lifelines are 6mm plus an extra cover. The lower 4mm plus cover. The forward end is a loop and brummel splice. The rear end is a loop and thimble and then lashing (same as the SS ones).

Our previous SS ones had rusted in parts under the plastic. The new ones are easy to inspect/change. Cheaper than SS replacement. Breaking strain is probably north of 6000kg (ie you could lift the boat... just). Main risk is chaffe.

Buy your Dyneema on ebay or the boatshow and it can be really cheap.

 

[oldmanofthehills]

I read an article about the us coastguard testing knots in dyneema. The best knot gave up at only 13% of the breaking load of the dyneema

Aparently the worst offender for climbers was the classic larksfoot on carabiner; ie a loop passed through itself. The end of the loop sliced through the main strand as no friction to mute its cutting ability if the whole lot looped over smooth metal of carabiner.

Figure of eight or scaffolders knot everytime. Scaffolders has little negative impact but disastrous if wrong as cord then slips through but figure of 8 hard to get wrong. If dyneema oversized for handling then a 15 or 20% reduction in strength still leaves good margin