I decided to replace the upper portion of the lazy jacks with amsteel blue and friction rings instead of blocks. I just finished all the splicing and was admiring my work when I realized something - there might be significant chafe because the lines start on the forward part of the mast. Should I ditch my beautifully spliced and return to vinyl covered wire? Do the tangs where the lines are fixed provide enough clearance from the mast?
Michael Belanich
Dolcetto, F38 #65
I replaced my wire with dyneema about a year ago. About 800 miles on the boat since then with no problems. Well, one problem. Despite what they say, dyneema stretches a little. I got a smack in the head taking in a reef before I dialed in the stretch and resultant boom sag. Seems less stretchy now so maybe that was only when the lazy jacks were new. I have not seen any chafe but have not been up the mast since I installed them. Never noticed much movement at the point were the jacks bend around the mast so hopefully not a problem. Going up there in a week or two and will check it out.
Unless you bought ‘pre-stretched’ line, dyneema single braid always has a little “construction stretch” when first loaded up as the braid tightens. That’s one of the reasons new line is easier to splice than old line that’s been heavily loaded.
I wouldn’t worry too much about chafe with dyneema, but if you do I’d suggest whipping the area of possible contact with a small diameter waxed whipping line. I like to use hi-test (250lb-300lb) braided dyneema fishing line [around 1mm diameter], that I drag through a piece of beeswax before use. The beeswax helps keep the whipping in place on the rope while you’re doing the whipping, makes the thin whipping line easier to grip and adds a bit of lubrication in use. I buy 100m (325ft) spools on ebay for around $10 [but ships from China on a slow boat]. The beeswax came from an old candle, but the local fabric/sewing shops also sell small chunks.
If you see the whipping begin to come loose and unwinding from the upper end of the lazy jack, you know you’ve had enough chafing to wear through the whipping and it’s time to climb the mast and fix the problem. But realistically with the very small amount of movement and low loads seen by the lazy jack I’d expect it to last for decades.
Ah, very interesting, seems to match my experience very clsely.