Marine Forensic Technicians
Marine Forensic Technicians, Stevensville, Maryland - James R. (Randy) Renn, SAMS® AMS® Marine Surveyors
Stevensville, Maryland

James R. (Randy) Renn, SAMS® AMS®
Principal Marine Surveyor
Damage & Insurance Loss Specialist

Worldwide Service




Some Straight Scoop on a Straight Course
Hello there and good day fellow boater! Here we are again with another subject to discuss. This time we have to ask if you are ready and that means really ready to be introduced to one of the more excitingly breathtaking and least discussed areas of your boat? This subject is so scintillating and tantalizing that children are asked to leave the room when discussing it. In fact, the subject is so controversial, that it is somewhat like global warming, if we do not mention it maybe it will go away. Yes, you have guessed it….steering parts or more specifically steering "stuffing boxes". For the sake of this article I will mostly focus on the most common of steering parts found in most inboard power and sail boats.

The culprits in this tale are made up of the rudder port usually referred to as a "stuffing" box, a rudder or two, steering cable or hydraulic ram, steering helm and steering arm or "tiller arm". One reason for major concern in this area lays in the fact that a rudder post left unattended in time, will develop a significant water leak. Also like any component given to movement the rudder port, rudder arm, pivots, bushings and rudder shaft will wear, rust or even seize. We have seen leaks that will cycle bilge pumps on an hourly basis and that is not a good thing! Further your hydraulic ram can develop leaks at its seals, lose pressure and you lose steering-usually between the rock jetties with a following sea.

Just what is it we are looking for? Gazing into the machinery space in the after section of your hull, you will find your rudder port(s)-bronze, rudder shaft-stainless steel, rudder tiller arm-likely bronze and steering ram or cable also stainless. Taking these items one at a time, we can see how and why they wear and what we can do about the various situations.

If the vessel is out of the water in anticipation of spring you would walk up to the stern, stare at the rudder(s) and check if any is bent, badly corroded, eaten by erosion, etc. If there are two rudders they will not be parallel. They cannot be as a certain amount of misalignment is built into the hull design so do not worry about that. The rudders should be parallel when seen from one side or the other. If one is further aft than the other, this indicates that grounding you had last year really did do a bit of damage and you should consult your local technician. Rarely will a slightly bent rudder require replacement. What you should do next is to grab the bottom of a rudder and work it back and forth at right angles to the keel and then along the keel line. On power boats there should be very little movement and no "Clunk". Sailboats may have more play due to the rudder lengths but should not have discernable "Clunk". These "Clunk" sounds indicate wear in the rudders port or rudder shaft. Next you would hold the rudder by its forward and aft edge and twist quickly and firmly as if the rudder was turning during steering. There should be little or no "Clank", a very metallic sound. If you detect "Clank", you have metal wear that might be one of several items we will discuss in the next paragraphs.

With the boat in the water let us observe the situation. Is the rudder port leaking sea water? Let us for a moment assume that it is-almost always. We will know this by seawater seeping around the rudder shaft. There may also be water seeping from under the base of the port where it is bolted to the hull. Unless you are able to dry the port and surround area completely, you may have to wait to determine if the base is leaking.

As the photo indicates the rudder port is made up of four parts. The base, which is bolted to the hull. The packing "that square string material", the Gland which is the cap with a hole in it for the shaft that screws unto the Base, and the Jam nut that is used to lock the gland once it is adjusted. The system works when in place, with the rudder shaft in it by the gland compressing the packing around the shaft making it water tight. This does not require a great deal of pressure. The rudder port is almost identical in construction and concept to a propeller shaft arrangement, except that it is not mounted on a flexible hose, and is not subjected to millions of rotational cycles. Unlike the propeller stuffing box, which simply floats on the propeller shaft, the rudder port is subjected to considerable side loading. The side loads can be intense, and the larger the rudder surface and vessel speed, the greater the loading.

Alright, the gland has water weeping what do you do? The procedure is quite simple if sometimes awkward. The first step is to loosen the jam nut. The jam nut is rather thin and your access can be limited, AND it has been there for perhaps a very long time. Be absolutely certain there is someone with you in case you get stuck, and be very sure the person is no where near the helm as you do not need anyone anywhere near the helm while you are entangled with steering parts. Also make sure the ships electronics are turned and locked off so the Autohelm will not engage. In as much as you can clean the salt, old grease and general corrosion from the ports threads and apply medium grease. Using an adjustable wrench or large channel lock pliers you loosen the jam nut two or three complete turns away from the gland nut, remember rightie tightie and leftie loosie. I suggest if you are able to tap the jam nut with a long punch and hammer to free it off the gland nut, do so. Jam nuts can be very tight and sometimes difficult to access so be patient. Right about here you have dropped something into the bilge so take a break and plan your next move. The next move is to see if tightening the gland nut will stop the water weep. Looking down on the gland nut and using Channel lock pliers or a pipe wrench, turn the gland nut slowly clockwise and within a just few quarter turns the water weep should stop. When the weep stops stop tightening. Going too far is not better, enough is enough.

If the leak does not stop and you have turned the gland down two and one half to three complete turns, you have a bigger problem calling for more effort. That effort will entail loosening the gland nut completely off the rudder port base and then extracting the old packing from inside the gland nut using a packing pick-about $12. A large dental pick really of very hard steel. The old packing will be hard and can be difficult to remove. It may be that the rudder arm is too close to the gland for removal and/or there is an upper rudder bearing with a wear bushing. Even if you can move the gland nut up and off the rudder port, getting the packing out in what will now be a fountain of seawater will be a trick. Have had a customer who sheepishly admitted that he had removed the rudder arm, lifted the upper bearing, loosened the gland nut and was going along famously until the rudder fell out of the boat! The best solution is to have the boat out of the water, remove the rudder parts and drop the rudder for shaft inspection.

At this point you might wish to remove the rudder port-four bolts, as a matter of course and reseal it to the hull. If you had a large amount of rudder "Clunk", the choice may now be to have a machine shop mill your rudder port and install a bushing or to replace the port with a new unit. It is probable that machining costs might be as costly as a new unit. By example, a new unit for a 11/4" shaft is approximately $140.00. Check your rudder shaft and if it is galled or grooved, consult your technician as it can be difficult to seal worn shafts.

When installing new packing the new material, it is important to cut the material to shaft size and on an angle-see photo and use 2-3 rings with the cuts at different locations. The packing comes in sizes so save an old piece for size reference. You will find packing in "Waxed Flax" and "Silicone" materials and both are square, easy to cut and close in price. Material should cost $8-10 for enough for three rings at 11/4". Pricing goes up quickly as size increases. New material once installed should be checked as it will take a set shortly after installation and may weep again slightly. Remember do not over tighten.

Well we have addressed the weeping rudder port how about the other components and what about that "Clank". If you had a Clank there are several placed to look. The presence of bronze dust at the pivot ends of the rudder arms are a sure giveaway that the bronze arms are wearing. Take a close look at the pin or bolt for the steering ram or cable. This point should have no wobble at all. If the pivot pins or bolts are loose in the arms, it is likely the arms would require having bushings installed. I really do not recommend this procedure as it means boring the rudder arm to accommodate the bushing and that means removing some of the arm strength: remember that heavy load thing. Rudder arms are $55.00 for our 11/4" shaft and that should be less than machining. If you have a twin engine arrangement, there is a link arm between the rudder arms with pivot points and pins that will wear and clatter while underway. If you have been searching for the annoying rattle while under way, you may have found it. In most cases the link arm is common steel or galvanized pipe, both of which will corrode and weaken. If the link arm is pitted, it should be replaced along with ends and pivot pins.

There are two other areas that can create some issues and Clank. One of concern to surveyors and often found is in way of the hydraulic system ram mounting bolts. It is unusual that the maximum throw of the systems ram happens to coincide with the maximum swing of the rudder arm. More likely the hydraulic ram travel is greater than the arm swing distance. This means that when you go hard over to a steering stop position, you are applying between 600 and 1,500lbs. of force on what is commonly four ¼-5/16" bolts or lags usually mounted on or in wood. In the fullness of time, the wood in which the fasteners are fixed ages, gets compressed or the holes in the wood simply wear out due to thousands of load cycles. If it is not obvious that the ram mounting plate or fasteners are moving, you can ask your friend to swing the wheel in short strokes back and forth while you stand clear and watch for movement in parts that should stay still. Also a good time to look for Clanks at upper rudder bearings if fitted. Another area is in the steering cable and hydraulic ram ball pivot. This is where the cable or ram is attached to its pivot block. Look for movement-Clank at this captured ball joint. There should not be any and in the case of the cable, the holder should not be rusted. While you are in the vicinity take a moment and look at the vessels green wire bonding system for connections and wear.

The last areas are the hydraulic ram and helm seals. The helm seal will be real simple to locate as a leaking seal will drip hydraulic fluid on your deck shoes. Helms need to be filled just like the steering on your car and use a fluid available at any ships store. Hydraulic rams leaks may not be as easy to spot, but a quick wipe down of the ram will show a red staining and the indication of weeping seals. Seals will not heal themselves and loose steering underway can ruin your afternoon. The photos of the single rudder arrangement shows several common issues. The steering arm pivot bolt is badly rusted, rudder port is leaking badly, the steering ram mounting bolts are very small and mounted into wood under fiberglass and the hydraulic ram is leaking and weeping fluid into the bilge. Unfortunately this boat is owned by a Marine Surveyor who writes Maintenance Articles for Boating Magazines.

What you will need.
Square flax packing - $8-10
Medium marine grease-$7.50
Pick(packing puller-$12-13,
Wrenches, pipe and adjustable.
Hammer and long punch.
Large-14-18" Channel Lock Pliers
Large standard pliers
Small, wiry, strong person who enjoys bruises

All the best in boating and keep it off the lee shore

James R. Renn, AMS-E

James "Randy" Renn is a Marine Surveyor with Marine Forensic Technicians. He has been an independent hull and engine surveyor for 20 + years. He has spent 30 Years in the Industry and now acts as Mid Atlantic Regional Director for the Society of Accredited Marine Surveyors as well as International Standards Liaison for that group. As an agent for CE Proof Mr. Renn inspects vessel and machinery for export to CE Member States and is a member of the International Institute of Marine Surveying.

Go to main page.

Copyright © 2008/2018 Marine Forensic Technicians, Stevensville, Maryland - randyrenn@aol.com
Installed March 15, 2008, Last Update November 24, 2018 - Hosted and Maintained by Don Robertson