In the world of sailboat standing rigging there are three common materials used, stainless steel wire, Nitronic 50 rod, and various types of synthetic fibers, which are becoming more and more popular. I want to talk today about Nitronic 50 stainless steel rod. This specific type of stainless steel is very strong and noble. Rod rigging can provide lower stretch, less windage and reduced weight characteristics than its wire counterparts.
So if your boat is equipped with rod rigging, what maintenance schedule should one adhere to? In order to maintain your rod rigging or any rigging for that matter, it is highly recommended to simply wash and rinse the hardware with soap and water. This in itself can make a big difference.
The general guidelines for rod head inspection and service are 40,000 – 60,000 miles or 6 years, whichever comes first. Rods, tangs and fittings, generally should be replaced once the rig exceeds 120,ooo NM. This is a generalization that will vary by geographical region and use. Typically (at least in my experience) one will find that they reach the 6 year mark before the 60,000 miles. The rod head service is extremely important and should not be overlooked. In order to inspect/service your rod the mast will need to be un-stepped.
Rod heads are made by a hydraulic cold press machine that utilizes a series of dies, clamps and rams to press a head onto the rod. The rod heads are responsible for keeping the fitting from slipping off. The rods themselves can last a very, very long time. Much longer than the expected life span of wire. This is due primarily to the type of metal used, how it is treated, and also the construction characteristics of the wire vs that of the rod. Rod cold heads are prone to cracking and should go no longer than 6 years without being serviced.
With some type of rod fittings the head can easily be accessed, cleaned up and inspected for cracking. However, other types of fittings will be dimpled and can therefore not be undone to be inspected. In this case you will need to replace the fitting as well as the head. This does not necessarily mean the rod needs to be replaced. The length lost will be minimal and is usually within the throw of a turnbuckle.
There are some instances where the entire rod will need replacing. If the rod has been damaged, bent or kinked, one should replace it. Navtec guidelines talk about it being acceptable to bend the rod back only once if the bend isn’t too severe. Personally, I would get replaced, because I don’t like ‘ifs’).
Another situation that would call for rod replacement, is when a head needs to be replaced aloft on a shroud which utilizes a spreader bend. A spreader bend is an aluminum or stainless sleeve that is slipped onto the rod before heading and is bent in place to a designated angle at the point where the rod intersects the out board spreader end. As there is no turnbuckle at the top end of a stay (at least not typically, that would be weird), the loss of length can not be made up for by turnbuckle adjustment. In other words the spreader angle would no longer be the same. Lastly, you would need to replace any rod that simply does not have enough length for re-heading. This is rare but can happen especially if the rod has been re-headed several times.
Regarding terminals, if using a rigging screw type turnbuckle (see picture) make sure your rigger knows to replace the screw itself. These are also very prone to fatigue and aging. A good school of thought here is, any terminals that look extremely old and worn should be replaced. This should be evaluated on a case by case bases. Remember, it is always recommended to seek the advice of a professional. At least at The Rigging Company, advice is always FREE of charge.
Read here for more info from Navtec on how to maintain your rig!
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