Before deciding to do my own standing rigging using compression terminals like Hayn Hi-Mod or Sta-Lok, I did a ton of research… Watching videos, reading online articles and discussions, reading manuals and literature.
The experience of actually building new standing rigging, however, taught me several lessons which were rarely mentioned nor given proper emphasis for importance.
(I built my new rigging using a combination of Hayn Hi-Mod and Sta-Lok. Hayn is my personal preference, but they do not offer stemball terminals.)
I’ve collected these lessons here for your benefit, dear reader.
1. Look for those funky fittings
Having never had my mast and rigging down before–or anyone’s mast and rigging for that matter–I was surprised by the variety of terminals represented. It might take some effort, but keep looking and you may just find those stemballs and t-balls you’re looking for. Though it may mean having to employ terminals from multiple manufacturers in your re-rig.
2. New turnbuckles to one-third engaged
The typical process is to measure the length of the old stays with the turnbuckles set to where they were when the stays were tensioned, then use that length when making the new stays.
So when measuring/determining the length of the new rigging, do so with turnbuckles one-third engaged.
This will give a little turnbuckle adjustment wiggle room to deal with the fact that stainless steel wire rope stretches a bit once it is placed under tension. However, this isn’t necessary for short stays like bob and whisker stays, so those can be done with the turnbuckles threaded closer to halfway.
3. Measure carefully, but don’t sweat it (too much)
Get the measurements as close as you can, but don’t sweat it too much. Being off by a fraction of an inch will be ok–that’s what the turnbuckle is for.
4. Appropriate working surface for wire
To prevent scratches and dings on new stainless steel wire rope, use a smooth working surface. If the surface is concrete or asphalt, such as you might encounter at a boatyard, cover the ground with cardboard, a tarp, etc.
5. Keep cool while cutting
If cutting the stainless steel wire rope with a power tool, keep it cool while cutting by continually pouring a small but steady stream of water onto the cut site. If you do so, the wire won’t discolor and it’ll be easier to cut. You might get a little wet.
6. Rinse and wipe after cutting
After cutting, rinse the end of the wire in fresh water and wipe clean. It’s not known for sure, but it’s suspected that one case of early compression terminal rust may have been due to dust/residue left on the wire after cutting with a grinder.
7. Rotate but do not bend the outer strands
Some drawings in manufacturer literature are absolutely atrocious and give the impression you might use a screwdriver to bend the strands into a chaotic, unwieldy mess. Do not do this.
For wire up to 3/8″ diameter, no tools were required to unravel the outer strands except my finger nails. Rotate each outer strand in sequence around the inner core. Move the outer strands one at a time, in order, gently working each one around without bending. The last two or three will be the most challenging. You should end up with something that looks reminiscent of a flower.
8. Go in the direction that tightens the strands
When assembling or closing up the terminal, or when rearranging the strands to get them into their slots (Hi-Mod) or avoid the cone/wedge crack (Sta-Lok), always go in the direction that would tighten the outer strands of the wire.
9. Test tighten, open and check before final tighten
Before final tightening of the terminal, give it a test tighten and then open it up to check to make sure everything is the way it should be. This is important for all terminals, but absolutely critical for the Sta-Loks, because if a wire strand is caught in the cone’s crevice, it will not be able to clamp down on the wire properly and very well may substantially weaken the holding power of the terminal.
For this test tighten, don’t tighten too much. This is just to make sure everything’s in place. If something’s amiss, you want to be able to correct it, not make it permanent. Besides, no thread locker or lubricant has been applied yet, so excess force at this stage could seize the threads.
For the Hi-Mods, you want to check that the proper amount of wire is sticking out past the end of the crown ring, that each outer strand is in its own slot in the crown ring (two per slot for small-diameter wire), that the end of the wire and strands are even, and that everything looks smooth and orderly. When re-assembling after inspection, be sure to hold the terminal against the crown ring when threading the body onto the terminal, to keep the cone from slipping upward toward the bitter end of the wire.
For the Sta-Loks, most important is to check that there is no wire strand stuck in or interfering with the cone. The closest strand should pass over the crevice at an angle, and not be trapped anywhere inside; and all of the strands should be evenly spaced around the cone. If you do find a wayward strand, gently lift it out without bending, and rotate it–and any other necessary strands–around (in the direction that would tighten the strands closer to the core, see #8) until no strand is stuck in the cone and all strands are evenly spaced. Then repeat this test tightening step to check your work.
10. Don’t get caught in the cone!
This warning is so crucial for Sta-Loks it’s worth repeating. If a wire strand is stuck in the cone’s crevice and prevents it from closing, the terminal could fail at a lower load than it otherwise would. That could mean injury or loss of the mast.
11. Watch the threads, man
Use something on the threads to prevent seizure/galling–a thread locker compound (discussed below) or thread lubricant.
However, before you do so, be sure to clean the threads to remove any machining oil or pre-applied thread lubricant.
12. Loctite the stemball heads
Unlike swaged stemballs, the body of a Sta-Lok stemball is too wide to go through a stemball receptacle. So, the stemball portion of the terminal screws onto the body. This means, though, that the thing working itself loose over time is a potential concern.
For this reason, I recommend applying Loctite to the steamball head threads when attaching the stays to the mast. A Sta-Lok representative indicated that either red or blue Loctite would work for this purpose. I chose to go with blue Loctite 243 (more on that below), but still wonder if it might work loose. I’ll be keeping an eye on this and will update this post with my experience.
13. Red pill or blue pill–er, Loctite?
In my opinion, you really should use something on the threads to keep them from seizing or galling. That means a thread locker or lubricant compound. My thinking is, if you’re going to the trouble of applying something, it may as well be a thread locker in this case since you don’t really want these puppies coming loose on you.
It is then a choice between the red and the blue flavors. I went with blue Loctite 243, which offers these advantages over red:
- It does not require a primer to be applied on stainless steel
- It can be loosened when needed using tools; heat not necessary
One of the nice benefits of compression terminals over swaged is the ability to open them and inspect. Red Loctite works agains this benefit.
Having said this, I have not yet personally “battlefield tested” the blue Loctite for this purpose. But I used it for my re-rig, so I will update this post with my experience after a time.
Note that in the online reviews for Loctite on Amazon, there was concern expressed about the authenticity of some bottles received. As a result, I ordered from Grainger; it’s pricier, but they’re an official distributor, and I didn’t want to take chances with my terminals working loose.
14. To fill or not to fill?
I think someone may have once said something about the mysteries in life being what keeps it exciting. Well one of those great mysteries seems to be whether or not to fill your compression terminals with polysulfide or some other kind of sealant gunk. And friends, I gotta tell you, it’s too much “excitement” for me.
Ambiguity from the manufacturers doesn’t help. Hayn’s instructions say sealant is not necessary, but you can use some if you want. Huh? And I could swear Sta-Lok said somewhere to use sealant, but now I can’t find any mention of it in their literature.
The concern is the same as any time sealant is used around stainless steel–if salt water does manage to get in past the sealant, then there will be no oxygen present to give the steel its stainless property.
Furthermore, sealing the innards away also works against the nice feature of being able to open and inspect the terminals. What could you inspect in there but a big ol’ chunk of goop? At least, not without having to clean it all out and then re-apply it upon re-assembly.
On the other hand, there is this forum thread which suggests that due to the fabrication/shape of Sta-Loks, without sealant in the terminal water can pool internally and lead to corrosion. (And I don’t see how Hayn terminals would be any different, unless water that gets inside can somehow pass by the threads.)
In the end, I decided to go without sealant. This should be fine for the Sta-Lok stemballs in use: they’re up the mast a ways and not as exposed to salt water. Besides, they’re inverted, and so shouldn’t be subject to the cupping/pooling problem in that orientation. However, time will tell if this was the right choice for the Hayn terminals that will regularly encounter sea water.
15. Critical! Roller Furler Considerations
Update April 2021: I’ve recently become aware of a third-hand account of a small number of headstay failures due to the compression fittings coming unscrewed over time as a result of the roller furler rotating on the headstay. The particular brand(s) of fittings involved is unknown to me.
Because of this, consider using swaged terminals for the headstay; or if you stick with compression fittings, close them using a fresh vial of red Loctite. I say fresh because apparently red Loctite’s adhesive properties can degrade over time once opened. So for this job, skip the ancient dusty bottle in the lazarette. Finally, play close attention to whether your Loctite requires use of a primer.
- Mechanical Terminal Pull Test (Practical Sailor, April 2016)
- Screw-On Rigging Terminals (Practical Sailor, June 2015)
- “Wire Terminal Destruction Test” (Practical Sailor, May 15, 1993)
- Hayn Wire Rigging Catalog (PDF)
- Hi-MOD Compression Fittings Installation
- Hi-MOD Compression Fitting Installation (video)
- Sta-Lok Rigging Hardware Catalog (PDF)
- How to Install Sta-Lok fittings by Sailing Project Atticus (video)