Synthetic Lifelines Part II

27 Mar

I got my spider-wire in the mail today. That’s the name we’ve given this stuff. This length of 5mm Dynex Dux along with the deadeyes and pelican hooks will become double lifelines for the boat.

While waiting for the line, I’ve been working on the deadeyes and varnishing my (minimal) brightwork. I’ve been very busy and things are moving along faster than they have in at least a year but sometimes I find that when things are going well on the boat I’m not much good at keeping up with writing about it. All too often the comparatively instant gratification of putting on another glistening coat of varnish or playing with the router wins out over sitting at the computer. At least I’m building up a good stockpile of things to write about! Here’s one example:

These are the deadeyes which will be the heart of my lifelines. The Dynex Dux rope is staggeringly strong (my 5mm lifelines have a breaking strength of 10,000lbs) but it loses up to half of this strength if you force it through too sharp of a bend. When rigging up synthetic lifelines some people give in to the temptation to lash the line directly to the pulpit but in doing so they sacrifice much of its strength. It is far better to splice the ends of the line over an eye which has a minimum 5/1 radius to your line. This means a 5mm line requires an eye where the radius of the curve is 25mm. To do this you need either a splicing thimble or a deadeye. This eye can then be tied/tensioned to your pushpit/pulpit/pelican hook with a lanyard of high-modulus line.

Photo Credit: Colligo Marine

Colligo Marine makes these lifeline ‘Terminators’ from hard-coat anodized aluminum. I considered using them but then decided it would be a fun project to make my own more traditional wooden deadeyes.
The first step was finding good wood. For a job like this I needed something very strong and rot-resistant. Fortunately I had a chunk of some sort of ironwood which I friend gave me a while back.

After sketching out my design I made my rough cuts on a bandsaw.

Deadeyes rough- cut

Then I cleaned up my cuts on a disc sander with a coarse disc

Ready for shaping

Next was some work on the router to round the edges and cut my groove. Because the pieces are so small this was the most difficult part and rather scary. I didn’t take many pictures because I couldn’t figure out a way to do it that I would recommend to anyone else!

Rounded off
Routing a groove for the line to sit in

Afterward I counted my fingers, breathed a deep sigh of relief and moved on to the drill press. I marked each of my holes and indented them with a center-punch to try and get the bit to drill precisely where I wanted it but even so some were a bit off. A professional would probably have made some sort of drilling jig but I couldn’t be bothered. I figure the deadeyes will work just as well with slightly uneven holes and really who is going to look that close anyway?

After drilling I cleaned up the holes with a sanding drum

At this point the deadeyes are really starting to take shape. All that remains is to cut grooves so that the lanyard will have a fair lead.

I did this with a dremel and a small drum sanding bit.

I left one hole on each without a groove. This is meant to be for the stopper knot at the end of the lanyard but just as I finished the last one I noticed that by using the middle hole I had made it so that my lanyard will have to cross itself. Functionally this makes no difference but aesthetically it’s a bit sloppy. Oh well.

After grooving the holes I gave everything a quick 220-grit sand

Sanded and ready for oil

All that remains is to coat them for a little extra protection. Being some kind of tropical hardwood they ought to hold up fairly well so I decided just to oil them. I’ve been using pure tung oil mixed with mineral spirits. For the first few coats I used a lot of mineral spirits to help the tung oil penetrate and then I went to a 1:1 ratio. This is after the fourth coat:

I’ll put a few more coats on and then these will be ready to be spliced up.

See Part I here: Synthetic Lifelines in the Works

This article was syndicated from Safe At Harbour But Meant For The Sea: DIY Sailing with Paul Calder


  1. Justine Kilkerr

    This is so great. I’m planning on making my own lifelines and would love to see your completed ones, lashings, deadeyes and all! Like Frank, I’d really like to see a follow up of this post and a conclusion to your lifelines posts. Love your site :)

  2. Robert McCarty

    would it be all that hard to put a ruler on the table while taking pics, for those of us that might want to duplicate the nice work?

  3. Frank

    Paul nice job with the deadeyes. Maybe you could do a follow-up with the lashings, deadeyes, and lifelines completed. I’m thinking of doing this and That would be very helpful. Either way thanks for your effort.

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