Mast Maintenance;or how to avoid turning your sailboat into a powerboat.
The single greatest cause of sailors becoming power boaters is the lack of maintenance given to their spars and rigging. Many sailors simply sail their boats until the rig falls down. This practice is great for our business but bad for both insurance companies and boat owners. A simple inspection and replacement program can save a summers sailing, the crews' safety, and maybe the club championship.
The simplest and most important maintenance priority involves wash down, inspection and lubrication. Hosing down the spars after use, especially in salt water, rinses away salt and grime that degrades the surface of the spar and helps promote galvanic corrosion between dissimilar metals. The boom is especially prone to problems since many times it is wrapped in a wet mainsail and a sail cover to bake in the hot sun. Fresh, clean water will be a lot less harmful than salt or lake water would be.
While cleaning the spars, inspect the hardware, look for points of wear and other potential problems. High load areas such as the gooseneck and vang swivels or bails on the mast, and vang mainsheet and outhaul areas on the boom should receive special attention. Look for excessive corrosion, small cracks, deformation or other tell tale signs of potential problems. At least every six months enjoy the view from the top of your mast and go aloft to inspect and lubricate the masthead sheaves. Inspect all of the hardware along the mast including the spreader bases, shroud tangs, spreader tips and chafe protection, and masthead sheaves. This is also a great time to replace the anchor light bulb that has been out for the last two seasons. Check for cracks at any of the forward sheave boxes, such as the pole lift or staysail sheave, and at the hounds box on fractional rigs. These are areas that show fatigue first. Check the hardware for small cracks, excessive corrosion, and deformation. Check for halyard wear on the forward edges of the spreaders.
Mast tangs are usually either external type with a compression tube and bolt fixing them to the mast, or one of a variety of newer types including "T tangs" for wire or stemball tangs for rod and wire or screw together type rod tangs. All the types of tangs should be checked for corrosion, articulation, and proper mast wall bearing. Stress and corrosion can cause the tangs to crack or in some cases cause the attaching fasteners to become loose or ineffective. Corrosion can also cause the tangs to lose their ability to articulate as the mast moves which is a sure fatigue inducer in the shrouds. All tangs bear on the mast wall and the bearing point shoud be inspected to be sure that the tang is not "dragging" through the wall of the mast. Compression tubes and bolts should be inspected regularly, but this will require disassembly of the tangs and that is usually best done with the mast out of the boat. I have seen many compression tubes, bolts and tie rods nearly cut in half from improperly lead wire to rope halyards. I would plan to pull your mast for a thorough inspection every five years or less.
After battling the seagulls for room at the masthead, inspect the headstay and backstay toggles, chafe guards, and sheaves. The sheaves should be lubricated with a heavy lubricant. We recommend using heavy lubricants (Lanocote, or lithium grease or a combination of both) instead of light lubricants due to their ability to stand up under high loads and to prevent galling. Both Lanocote and lithium grease are available in aerosol cans with long plastic "noses" that can get to the center of the sheaves without disassembly. The exception is Harken sheaves which should be washed out with water and lightly lubricated. WD-40 is not a good lubricant for any use on spars, in fact it becomes glue like in salt water. I doubt that this dismissal will affect their stock price or their sales to unsuspecting sailors.
Lanocote has proven to be a miracle product for protecting from galvanic corrosion and galling. We use it on any parts that have to come apart again, such as spreader tips, spreader bolts, sheave pins and sheaves. It is made of lanolin and is pleasant to use and isn't messy like Never-Seize used to be. We call it "sheep dip" at our shop since lanolin is a component of sheep wool. In fact, for many years we had a Border Collie named "Mac" who used to sniff at an open tub of Lanocote with great excitement. He was so excited one day that he stepped in a tub and wore it for several laps around the shop before it fell off. 'Tef-Gel' is another widely used and very effective lubricant/corrosion prohibitor.
Another important area of inspection is the standing rigging. Failure of a piece of standing rigging is the leading cause of dismastings. A system of inspection and systematic replacement is the surest way to prevent the "powerboat syndrome."
Both rod and wire rigging have finite lives. They both fall prey to fatigue and corrosion over time. Wire rigging due to its construction and method of attaching fittings will probably fail from corrosion where as rod riggings' nemesis is primarily fatigue.
Corrosion in standing rigging is primarily "chloride type" corrosion where salt water in an oxygen free environment will activate the stainless steel and cause it to eat itself. This happens inside swage fittings with little obvious evidence until the wire and fitting part. Sometimes small crack will be apparent in the swage fitting from the corrosion expanding the parts, and sometimes not. Careful inspection can many times find problems, and if any wire strands are broken at the shank of the swage, the wire should be replaced immediately. Type 316 stainless steel is only marginally better protection from this "active" type corrosion than 302/304 stainless. Nitronic 50 rod, which is the alloy used for most rod rigging is quite corrosion resistant and most of the fittings are designed to drain, thus avoiding the problem. I do wish that Navtec would drill drain holes in their tip cups; they are always full with water when I inspect them.
Anaerobic corrosion also causes surface discoloration on the wire itself. Any type of coating on the wire surface (dirt, oil, and other surface contaminates) can keep oxygen from coming in contact with the surface of the stainless steel. If oxygen can not reach the surface of the stainless steel, the surface can not "passivate" itself and corrosion or staining can occur. I have seen this type of staining in all types (316 and 302/304 ss) and sources (US and imported) of stainless steel wire. The only way to avoid this staining is to keep the wire clean. I've often thought that calling a steel stainless on a sailboat was a marketing ploy.
Fatigue is many times less evident than corrosion but equally deadly to the vertical orientation of the rig. Wire is superior in indicating fatigue in that one or more stands will usually break before the entire bundle fails. Rod, on the other hand, consists of only one strand and is either continuous or broken. I have never found a piece of rod that is cracked and not broken. Fatigue usually occurs during use of the boat, but a loose stay or shroud flogging in the wind at the dock is also a prime candidate. Trailering a boat can also cause premature failure if the shrouds are not kept from bouncing around. The best prevention is to remove the wires from the mast before trailering. If that is not possible, they should be strapped tightly to the mast.
The areas that have been the most common sites for rod failure have been at the spreader tips (above or below the spreader bend on intermediate shrouds) and at the top fitting of the headstay. The headstay and intermediates are usually the first candidates for replacement, although replacing all of the rigging at once is usually the smartest plan. Although all boats are different, I would say that rod and wire rigging becomes suspect after about seven years of normal use.
The current trend in halyards is away from rope to wire halyards and toward all rope halyards. The rope halyards are usually lighter, and more kind to hands and the mast. They are, however, much more prone to chafe than wire halyards. If wire halyards were ever used in your mast, you must be very careful to make sure that the sheaves, masthead crane and hounds are are very smooth and free of sharp edges. Sometimes, chafe guards should be installed to protect the line, especially the main halyard. A few minutes with a file and sandpaper can save many dollars in new rope halyards. A sharp edge can ruin a new halyard in a matter of minutes.
Carefully check all of the halyards themselves. Wire halyards should be checked for breaks, "meat hooks," and integrity of the splice and nicopress . Rope halyards should be checked for chafe spots, cover bunching, and the integrity of the splice. All the shackles should be very carefully inspected, with a magnifying glass (for us old guys), to look for corrosion and cracking, especially in the hinge pin area. I do have one obvious suggestion, check the halyards before you go aloft on one to inspect the masthead. Also never trust just the shackle on the bosun's chair; always backup the shackle with a line laced through the spliced eye, or better yet, tie a bowline in the halyard and tie to that. You don't get second chances at the masthead.
With a little common sense and a few hours a year, sailing can be made safer and more enjoyable. I hope that this article has helped make both of these goals more attainable.
Buzz Ballenger, Ballenger Spar Systems, Inc.HOME