With the vinyl-coated wire lifelines on his 13.7m schooner Britannia well past their prime, Roger Hughes considered the replacement options. New wire – or Dyneema rope?
Lifelines are intended to stop someone falling overboard, so that’s the primary consideration in any replacement. But it raises another important question: how does a man overboard get back on board – through, or over the lifelines? The ability to lower lifelines can be a huge benefit – as was illustrated by my retrieval operation in the Mediterranean.
Thankfully it wasn’t a real emergency – we were at anchor. My charter guest climbed down the boarding ladder – foolishly with a woollen poncho over her togs because she was embarrassed by her obesity.
Dyneema lines pass neatly through the stanchions.
Within a few minutes the poncho was water-logged and the lady was in trouble. She was unable to get a foot even on the first rung of the boarding ladder, never mind climb back up. She jettisoned the poncho and clung to the ladder while I thought about how to get her back aboard.
Dropping the lifelines made the operation easier. The lady was too big to physically pull up the side of the boat, so I rigged the main boom with a snatch-block and a line with a loop big enough to pass around her back and under her arms. The inboard end was led to the windlass warping drum.
As I set this up, my wife released the pelican hooks on both lifelines and lowered them between two stanchions. The hapless lady was hoisted over the lowered lines, to plop on the deck like a landed fish. The only thing she suffered, apart from her dignity, was temporary bruising on her arms and back caused by the rope.
Roger’s old lifelines
Another real emergency that might benefit from lowering lifelines is launching a heavy liferaft from the deck. Britannia has an eight-man ocean raft which weighs over 70kg, in a canister on chocks in the centre of the deck. It’s too big to slide between the lifelines – they’d definitely need to be released or cut. The same problem might occur in manhandling a heavy dinghy stowed on deck, that needed to be launched in a hurry.
Most lifelines have pelican hooks at one end that can be released to lower the lines. Britannia’s were the old style, with a locking ring over the release lever. When the wires were tight it was very difficult to pry the ring back over the latch by hand – it required a pair of pliers.
Lines can also be released by unwinding the tensioning turnbuckle toggle at the other end, but if the line is tight unwinding the turnbuckle by hand can be difficult. If for any reason lines cannot be released, a final option would be to cut the wire, which requires long-handled wire cutters.
But what if the lifelines were rope? Easy to cut, but would rope be strong enough? Since I was replacing the wires, I decided to look at the pros and cons of wire and rope.
Using a turnbuckle tool to tighten the lines.
LIFELINE ALTERNATIVES
It didn’t start well. I couldn’t find any manufacturer who provided the strength of their material when used specifically as lifelines. All I could find (for both wire and rope) was ‘tensile strength,’ or ‘working load.’ No account is taken for stanchions either, which are integral to any boat’s lifeline system. How stanchions hold up depends on their deck fastenings, length, and tube thickness.
Whatever replacement I decided to use, it could be no thicker than 10mm, to pass through the 11mm holes through the stanchions.
My research settled on two options – white vinyl-coated stainless wire or Dyneema rope (in various colours) – each has its advantages and disadvantages.
WIRE – uncoated wire can become almost untouchably hot in the summer, and I don’t like gripping thin wire with bare hands anyway, so I didn’t want to consider that. Vinyl-coated wire looks smart when new, but over time water can enter at the ends and wherever chafe has exposed the wire. Eventually this causes corrosion that may not be visible under the covering. 4.8mm 7×7 strand wire has a working load of 1,678kg.
Freeing the pelican hooks on Britannia’s tired old lifelines.
ROPE – Dyneema is stronger, size-for-size, than stainless wire and substituting it for lifelines therefore becomes a viable possibility. 6mm single-braided, 12-strand has a tensile strength of 3,528kg.
Rope has a cost advantage: where 7×7 4.8mm vinyl-coated wire costs US$1.79 per foot (www.Defender.com), 6mm 12-strand Dyneema Ironlite in blue costs US$0.60 per foot (www.miamicordage.com).
But new end fittings will be an additional cost when replacing existing lines, especially if new turnbuckles and pelican hooks are needed. Stretch (creep) isn’t a significant issue: once tightened-up with the turnbuckles, wire does not stretch further. Dyneema only stretches about 1%, but once stretched doesn’t move much after that. Dyneema can be set up bar-tight.
All lifelines are subject to chafe – typically from sheets, lines, fender lines, and where they pass through stanchions. Britannia’s stanchions have a flared tube in each cross-through hole that minimises chafe at those points.
While white vinyl-coated wire is easily cleaned with a rag and some bleach now and again, it still fades over time. Dyneema has a shiny, slightly slippery texture that can be cleaned with soap and water and is available in many colours.
INSTALLATION CONSIDERATIONS
WIRE – I would need about 46m of wire and 16 threaded ends to replace my old wire, along with at least three new turnbuckles to replace the jammed old ones.
The conventional method of attaching threaded ends to wire is a swage fitting. A hand-swager tool is available from most rigging suppliers, but it’s tedious if you have a lot to do. First the vinyl coating has to be cut back a couple of inches, exposing the wire – in itself is not an easy job. It’s best done in a sturdy vice with a sharp box-cutter blade.
Then, using a wrench to tighten the bolts on the swager tool, five crimps are recommended on each fitting. I needed 16 fittings each with five swages – 80 crimps! Even if each swage only took five minutes, it would still take nearly seven hours.
Also, hand-swaging only produces 65% of the strength of the wire, but a crimping tool increases this to 85%.
An alternative method – ‘Sta-lok’ fittings – doesn’t require swaging or any special tools. These are easily assembled on wire using regular wrenches and actually provide 100% of the strength of the wire (also approved by Lloyds of London for lifeline fittings).
Boats with wire lifelines should preferably also have a goodquality wire cutter on board to chop the wire in an emergency.
Chafe guards fitted.
ROPE – it can be attached to existing toggle end fittings with either a splice or even a knot, but CS Johnson has special rope end attachments, called ‘Splice-Line’ lifeline fittings, to attach Dyneema to fittings like turnbuckles and pelican hooks.
The rope is spliced directly around the fitting without a thimble, and chafe is reduced to a minimum. Single-braid Dyneema is hollow, with no centre core and much easier to eye-splice than double-braided line. The 12-strand rope is first tapered by removing four pairs of strands, then the end is buried deep inside the standing part and lock-stitched.
This is an easy operation with a special 14-inch-long splicing wand from Brion Toss rigging (www.rigging@briontoss.com). This fid enables the tapered end to be gripped by the wand, then pulled through the core, instead of pushing it with a conventional fid. With 16 splices to make, I was very thankful to have one. It can also be used for other rope work.
I would need about 61m of rope, allowing enough for 16 eyesplices. I estimated it would take about three hours to do them all. My decision was made – Dyneema it would be.
I decided to do the job properly with new parts. I used CS Johnson Splice-Line rope fittings, including new turnbuckles and beautifully crafted quick-release pelican hooks. The whole installation took two weekends to replace all the old lifelines, and I eventually got down to 10 minutes for each Dyneema splice. Practice makes perfect.
There was one final thing I decided to do: since the only thing which can weaken Dyneema is chafe, I decided to enclose the upper lines with plastic covers, which clip completely over the rope and act as chafe guards.
One of the areas where chafe is likely is where it passes through stanchions and the 8mm plastic pipe will fit through Britannia’s stanchion holes making a smooth passage, yet still allow the rope to move freely inside. If any of the guards show signs of chafe from ropes or other sources it will be a simple matter to replace one section, before it wears the rope itself. The covers also increase the line thickness to nearly 13mm, which makes holding the lines much more comfortable.
Britannia’s finished lines now look very stylish and purposeful, and I’m confident that in the event of a real man-overboard emergency I will have the least possible obstructions to get the person back up the side of the boat, past the lines. I just hope I won’t be the first guinea-pig to test the system for real. BNZ
Britannia with finished Dyneema lifelines fitted.
MANUFACTURERS
Miami Cordage Inc. 1/4-inch Ironlite Dyneema: www.miamicordage.com
CS Johnson Inc. has a very comprehensive catalogue of lifeline fittings for both wire and rope: Flipbook (csjohnson.com)
Brion Toss Rigging for the splice wand: www.rigging@briontoss.com
STRENGTH TEST
Before switching to rope, I wanted an answer to one important question. Ignoring the manufacturer’s specification, I wanted to test the actual breaking strain of my Dyneema lifeline.
Miami Cordage has ‘The Rack’ – a hydraulic rope-testing machine (Government-inspected since it sells product to the US Navy). I submitted a 10-foot 1/4in Dyneema sample with eye splices at both ends.
I watched as the machine’s digital dial crept past 2,000 lbs. I expected to see a splice break any moment, but they held fast at 4,000lbs when the rope looked as tight as an iron bar. The rope finally snapped at an incredible 7596lbs (3446kg)! Yet both my splices held! That’s 3.4 Imperial tons! I have an official test certificate.
I’m now considering swapping Britannia’s standing and running rigging for Dyneema…
ROPE VS WIRE ADVANTAGES
• 6mm Dyneema is much stronger than 4.8mm wire. Dyneema 8000lb/3629kg; wire 3700lb/1769kg.
• Dyneema is not subject to corrosion or affected by rain or seawater and is easily inspected for chafe.
• Any section of a rope lifeline can easily be lowered between stanchions, because the line slides through the stanchions and bends easily. Wire does not slide or bend very easily.
• If necessary, rope lifelines can be cut with a sharp knife. Wire needs a long-handled wire cutter.
• Rope lifelines can be replaced without tools or fittings, even on a passage.
• A spare 50-foot length of 6mm Dyneema is much easier to store than the same length of wire.
• Dyneema is very much lighter than wire rope. My complete wire lines weighed 13lb/6kg (old lines). The same length of Dyneema rope weighed only 2.4lb/1.1kg. This started me thinking about the weight saving in my schooner’s 700 feet/213m of 4.8mm stainless steel standing rigging.
