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To Swivel or to Twist, That is The QuestionBy Captains Alex & Daria Blackwell To a cruiser, anchoring tackle is perhaps one of the most important pieces of gear – second only to the boat itself. As such, any mention of the pros or cons of any particular component or configuration will inevitably lead to some pretty strong opinions. We should know, having written Happy Hooking – the Art of Anchoring, though highly acclaimed and as impartial as we felt able to make it, our book, and subsequent articles have stirred up the occasional hornet’s nest of ‘discussion’. So it was with our chapter on swivels. To date we have shunned them, viewing swivels as an unnecessary weak link in the components connecting the sea bed to our boat. Yes, we have swung at anchor for weeks at a time while cruising. Where the wind was heavy, our anchor veered as a good anchor should. In light wind situations we did note that our chain was occasionally twisted, but this always corrected itself when we weighed anchor. The twist cannot get past the toothed wildcat on our windlass, so there is no chance that the twisted chain would find its way into our chain locker. The anchor simply spins while coming up and any twist is straightened out. Another reason many people opt for a swivel is that they fear that the protruding shackle pin might get stuck on the bow roller when deploying or weighing anchor. Unless the bow roller assembly has been very poorly designed, this should not be an issue. We have literally anchored thousands of times sometime two or three times in one day and have never seen this happen.
Swivel failure
The problem with all of these swivels is that their shaft is hidden from view. Should the shaft rust, which would seem to be likely as the space around it will remain moist, then it will no longer be as strong as it once was.
A note on stainless steel shackles and swivels.Stainless steel looks great. We were indeed very envious of our friend’s lovely shiny tackle particularly when next to our own dull galvanized anchor and chain. Even our shackles are dull, boring looking galvanized iron. On the other hand stainless steel, even the top grade 316, is more brittle, and thus not as strong as so called mild steel. Another chief characteristic of stainless steel is that it is smooth (and shiny). Galvanized shackles are rough and will bind when tightened properly. They can be difficult to open and are thus quite unlikely to ever open when they shouldn’t. Stainless steel shackles, on the other hand, do not bind and may come undone when least expected. This happened to me at the top of the mast when the shackle connecting my climbing gear to the halyard opened (but that is another story). Stainless steel shackles must thus always be seized with wire.
The chromium in stainless steel creates a passivation layer on the surface that protects the steel from rusting. In low oxygen situations and/or warm water this passivation layer breaks down and corrosion will set in. Low oxygen will occur in crevasses which stary wet (cracks, welds, shackle threads, keel bolts, etc.) or confined spaces (swivel shafts, etc.). Corrosion may also happen internally. Welding may cause the cromium to bind with carbon and thus indirectly lead to corrosion. We discuss this in greater deal in the upcoming third edition of Happy Hooking. So, where does this all leave us?With the Ultra swivel we have indeed been shown a swivel that appears to have very elegantly solved all the arguments we would put forward in opposition of using a swivel on an anchor rode. It obviates the need for a shackle, it has no hidden parts, it looks to be very strongly (and beautifully) constructed, and it moves laterally as well as twisting. Does this mean that it is advisable to add a swivel to an anchor rode? The way we see it, not really. As mentioned, we have on occasion spent months at anchor with wind and tide shifts. Our rode certainly had twists in it, but they all came out as we weighed anchor. With a permanent mooring, that is certainly a different matter, and a local mooring contractor would be the best to advise on this. In the final analysis, it remains up to the individual boater. There is good quality equipment available. So, if you feel you must go this way, then go you may! |
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