DIY
Sailboat Standing Rigging
Using 7x7 Wire, Flemish Eye Splices and Dyneema Lanyards
(Updated 2/20/2017)(See bottom of page for post-voyage updates)
In the process of outfitting our 1974 Cape Dory 25 for offshore sailing, we wanted to replace the original 1x19 stainless steel standing rigging. We wanted a method that was at
least as strong as the original rigging, reasonably easy to do and relatively inexpensive. Any
one of those conditions is fairly easy to meet, but all three is a challenge.
Mechanical fittings such as Sta-Lok and Norseman are easy, but expensive. Dependable swaged fittings have a reputation for occasionally failing, especially on the lower ends which are more exposed to saltwater. The best swaged fittings require a rigging shop equipped with a rotary swaging machine and experienced riggers. We considered Nicopress sleeves, which had worked well for me (David) on another offshore boat that I sailed to Hawaii many years ago. Nonetheless, long-term electrolysis between the copper sleeve and stainless wire was a concern. Also of concern was that the manufacturer (nicopress.com) specifies tin-plated copper sleeves for use with stainless steel wire rope. Unfortunately, it is difficult to find a vendor for tin-plated sleeves. Every online retailer we checked with only carried the zinc-plated copper variety.
After much research and experimenting, we decided on the method explained below and so far it has met all our requirements. It's relatively quick, doesn't require specialized tools, is stronger than our original rigging and is considerably less expensive than alternative types of standing rigging.
In short, it involves hand splicing eyes into 7x7 316 grade stainless steel cable. The spliced eyes fit into simple home made fittings constructed of 316 grade stainless steel bar stock. The rig is tensioned using simple deadeyes and lanyards with Dyneema rope, instead of more expensive stainless steel turnbuckles. No marine-specific fittings are used anywhere in the standing rigging. That includes all the mast tangs and chainplates.
Our original rigging was 1x19, 5/32" for the lower shrouds and 3/16" for the uppers and stays. Since 7x7 is a bit stretchier, we went up a size on both, to 3/16" and 1/4". 7x7 rope from Rigging Only was $0.98 per foot for 3/16" (5mm) and $1.62 per foot for 1/4" (6mm).
We also considered Dynex Dux, which was tempting until we got to the price, which was more than twice the price of the stainless steel wire rope we used.
According to the stretch chart on the Coligio Marine website, we'd need 6 and 7 mm Dynex Dux. They don't carry 6mm, but 5mm is listed at $2.85 per foot and 7mm at $4.06 per foot.
Standing rigging:
A few of the tools used:
Time-wise, the mast tangs and 9 chainplates were fabricated in a weekend. All the stays and shrouds were finished in a second weekend. Knowing that we can carry extra cable and can quickly replace any shroud or stay on the boat adds significantly to our confidence in the rig when we're offshore.
Since 7x7 cable has more stretch than 1x19 cable, we went up one diameter which gave similar stretch characteristics to 1x19 cable and a significant increase in strength. The original 1x19 rigging for the lower shrouds was 5/32", with 3/16" for the uppers and stays. On the new 7x7 rigging, we went up to 3/16" for the lowers and 1/4" for uppers and stays.
Researching online how to splice eyes into 7x7 cable, two methods stand out. One is the traditional Liverpool splice, which requires an expensive rigging vise and a fair amount of practice to master. It's not a user-friendly technique and typically takes a dozen or more practice splices before one begins to master it. The other notable splice is the Flemish eye splice, also known as a Molly Hogan. Although the latter is sometimes denigrated in online forums, master rigger Brian Toss notes that "Properly seized, it can approach 100% [of cable strength], but then you are counting on the seizings not chafing away." The method described below entirely avoids the issue of seizings chafing.
While I appreciated Brian's words, I wanted to test the technique for myself, so bought a 5' length of 1/8" 7x19 galvanized cable, which was as close to 7x7 cable as the local hardware store could provide. I spliced an eye in each end, but without applying seizing of any kind other than a few wraps of electrical tape just beyond each eye. I then hooked one eye over the towing hook on the front end of my pickup truck and secured the other end to a come-along anchored to a stout tree. All 4 truck tires were blocked with rocks and the hand brake was on. I ratcheted the come-along until the cable was bar-tight, at which point the truck wheels began to drag across the ground, rocks and all. The splices didn't budge.
I then found further confirmation in the following video by I&I Sling Inc., a professional sling manufacturer (scroll down to 'Flemished Eye Splices' and go to slide #5). The video dramatically demonstrates a Flemish eye splice in 1" diameter cable being tested to destruction. If you watch the video, note that the thimble on the splice is unpressed and therefore not adding to the strength of the splice. The eye finally breaks at 86,000 lb., or 87% of the breaking strength of the cable. While the cable size is far larger than a sailboat would use, the principle is the same.
Destruction testing aside, standing rigging is typically sized so as not to exceed 20% of the breaking strength of the cable, so an ample safety margin is provided.
In case it may be of interest, below is the splicing process I used. Although it looks like a long process, it only takes me about 20-30 minutes to complete a splice. An extra pair of hands are helpful for some of the steps. Before committing to stainless steel 7x7 wire rope, I recommend practicing with 3/16" or 1/4" diameter 7x19 galvanized wire, available at most hardware stores.
The 7x7 stainless 316 grade cable was purchased from Rigging Only (riggingandhardware.com), which had by far the best prices at $1.62 per foot for 1/4" and $0.98 for 3/16". The 316 grade stainless bar stock came from Online Metals. Fasteners, also 316 grade stainless, came from Bolt Depot (incredibly fast service, even across the country) and the 316 grade stainless steel hose clamps we got on Amazon. Dyneema rope for lanyards was ordered from Duckworks Boatbuilders Supply.
Here's what the finished splice looks like:
Mechanical fittings such as Sta-Lok and Norseman are easy, but expensive. Dependable swaged fittings have a reputation for occasionally failing, especially on the lower ends which are more exposed to saltwater. The best swaged fittings require a rigging shop equipped with a rotary swaging machine and experienced riggers. We considered Nicopress sleeves, which had worked well for me (David) on another offshore boat that I sailed to Hawaii many years ago. Nonetheless, long-term electrolysis between the copper sleeve and stainless wire was a concern. Also of concern was that the manufacturer (nicopress.com) specifies tin-plated copper sleeves for use with stainless steel wire rope. Unfortunately, it is difficult to find a vendor for tin-plated sleeves. Every online retailer we checked with only carried the zinc-plated copper variety.
After much research and experimenting, we decided on the method explained below and so far it has met all our requirements. It's relatively quick, doesn't require specialized tools, is stronger than our original rigging and is considerably less expensive than alternative types of standing rigging.
In short, it involves hand splicing eyes into 7x7 316 grade stainless steel cable. The spliced eyes fit into simple home made fittings constructed of 316 grade stainless steel bar stock. The rig is tensioned using simple deadeyes and lanyards with Dyneema rope, instead of more expensive stainless steel turnbuckles. No marine-specific fittings are used anywhere in the standing rigging. That includes all the mast tangs and chainplates.
Our original rigging was 1x19, 5/32" for the lower shrouds and 3/16" for the uppers and stays. Since 7x7 is a bit stretchier, we went up a size on both, to 3/16" and 1/4". 7x7 rope from Rigging Only was $0.98 per foot for 3/16" (5mm) and $1.62 per foot for 1/4" (6mm).
We also considered Dynex Dux, which was tempting until we got to the price, which was more than twice the price of the stainless steel wire rope we used.
According to the stretch chart on the Coligio Marine website, we'd need 6 and 7 mm Dynex Dux. They don't carry 6mm, but 5mm is listed at $2.85 per foot and 7mm at $4.06 per foot.
Standing rigging:
 At top is our DIY chainplate, deadeye and lanyard arrangement before setting up lanyard. At bottom is same, but with lanyard set up. All metal is type 316 stainless steel. Lanyard is 3/16" dyneema. |  Chainplate is on left, made of 3/16" x 1-1/2" flat bar. "Deadeye" is 1" long piece of 1" diameter pipe. Cheek plates for deadeye are of 1/8" x 1-1/2" flat bar. Bolts are 3/8" diameter. All metal is type 316 stainless steel. |
 Upper end of lanyard. Knot in dyneema is the improved Estar Knot. Eye in wire rope goes around a stack of 3/8" x 1-1/2" fender washers. Washers give a large diameter bearing surface for wire to go around, to help prevent wire fatigue. Bolts are secured with nylon insert lock nuts, lubed with lanolin to prevent galling, which stainless steel threads are otherwise prone to. |
A few of the tools used:
 Fabricating chainplates, mast tangs and cheek plates for deadeyes involved cutting stainless steel bar stock to length with a metal cutoff saw. Drilling stainless steel was fairly easy using either high speed steel or cobalt bits. The trick is to use the slowest speed on the drill press and to start with small bit and work up. For 3/8" holes, I begin with a 1/8" bit, then 1/4", 5/16" and finally 3/8". |  Stepping up to a larger bit. I didn't use oil while drilling, but did occasionally resharpen bits on a bench-mounted belt sander. |
 A stack of chainplates with more holes to be drilled. |  Bender used for bending deadeyes. My friend Erik gave us use of his shop and the various tools shown here. Thanks Erik! |
Time-wise, the mast tangs and 9 chainplates were fabricated in a weekend. All the stays and shrouds were finished in a second weekend. Knowing that we can carry extra cable and can quickly replace any shroud or stay on the boat adds significantly to our confidence in the rig when we're offshore.
Since 7x7 cable has more stretch than 1x19 cable, we went up one diameter which gave similar stretch characteristics to 1x19 cable and a significant increase in strength. The original 1x19 rigging for the lower shrouds was 5/32", with 3/16" for the uppers and stays. On the new 7x7 rigging, we went up to 3/16" for the lowers and 1/4" for uppers and stays.
Researching online how to splice eyes into 7x7 cable, two methods stand out. One is the traditional Liverpool splice, which requires an expensive rigging vise and a fair amount of practice to master. It's not a user-friendly technique and typically takes a dozen or more practice splices before one begins to master it. The other notable splice is the Flemish eye splice, also known as a Molly Hogan. Although the latter is sometimes denigrated in online forums, master rigger Brian Toss notes that "Properly seized, it can approach 100% [of cable strength], but then you are counting on the seizings not chafing away." The method described below entirely avoids the issue of seizings chafing.
While I appreciated Brian's words, I wanted to test the technique for myself, so bought a 5' length of 1/8" 7x19 galvanized cable, which was as close to 7x7 cable as the local hardware store could provide. I spliced an eye in each end, but without applying seizing of any kind other than a few wraps of electrical tape just beyond each eye. I then hooked one eye over the towing hook on the front end of my pickup truck and secured the other end to a come-along anchored to a stout tree. All 4 truck tires were blocked with rocks and the hand brake was on. I ratcheted the come-along until the cable was bar-tight, at which point the truck wheels began to drag across the ground, rocks and all. The splices didn't budge.
I then found further confirmation in the following video by I&I Sling Inc., a professional sling manufacturer (scroll down to 'Flemished Eye Splices' and go to slide #5). The video dramatically demonstrates a Flemish eye splice in 1" diameter cable being tested to destruction. If you watch the video, note that the thimble on the splice is unpressed and therefore not adding to the strength of the splice. The eye finally breaks at 86,000 lb., or 87% of the breaking strength of the cable. While the cable size is far larger than a sailboat would use, the principle is the same.
Destruction testing aside, standing rigging is typically sized so as not to exceed 20% of the breaking strength of the cable, so an ample safety margin is provided.
In case it may be of interest, below is the splicing process I used. Although it looks like a long process, it only takes me about 20-30 minutes to complete a splice. An extra pair of hands are helpful for some of the steps. Before committing to stainless steel 7x7 wire rope, I recommend practicing with 3/16" or 1/4" diameter 7x19 galvanized wire, available at most hardware stores.
The 7x7 stainless 316 grade cable was purchased from Rigging Only (riggingandhardware.com), which had by far the best prices at $1.62 per foot for 1/4" and $0.98 for 3/16". The 316 grade stainless bar stock came from Online Metals. Fasteners, also 316 grade stainless, came from Bolt Depot (incredibly fast service, even across the country) and the 316 grade stainless steel hose clamps we got on Amazon. Dyneema rope for lanyards was ordered from Duckworks Boatbuilders Supply.
Here's what the finished splice looks like:
