With proper and regular lubrication, the twin scourges of any cruising boat’s systems — friction and corrosion — can be banished forever.
A drip of oil, a daub of grease — both pay off when it comes to keeping rust and wear at bay.
Friction and corrosion. These, unfortunately, are constants aboard any cruising boat. However, with a little bit of periodic attention and maintenance, both can be all but eliminated. Friction comes into play the moment you start your vessel’s engine or generator. Were they not coated in oil, the crankshaft, connecting rod bearings, piston rings, rocker arms and cam shafts would quickly grind to a halt. Crankcase oil offsets the bulk of friction’s side effects, enabling engines to run for thousands of hours without ever having to be disassembled to replace any of these components. Oil also acts as a corrosion inhibitor by coating the engine parts that would otherwise rust or corrode.
It’s worth taking the time to select your diesel engine’s oil wisely, making certain it meets the manufacturer’s two-letter code, such as the American Petroleum Institute’s CI or CJ. Typically, the higher the second letter in this two-letter group, the more “modern” the oil. Virtually all diesels call for C-prefix oil, while gasoline engines utilize oil with an S prefix; never use S-prefix oil in a diesel engine. If your engine manufacturer calls for CF (which is now obsolete), for small auxiliaries it’s usually safe to use a current designation such as CI (API’S take on this subject: “For diesel engines, the latest category usually — but not always — includes the performance properties of an earlier category.”).
Be sure to follow your engine manufacturer’s guidelines for oil weight as well. Most modern diesel engines call for a multiweight oil, such as SAE (Society of Automotive Engineers) 15W-40, while some older engines specify a “straight” or single-weight oil, such as SAE 30 (that’s usually because it was the only option available when that engine was manufactured). Change the oil seasonally (typically when decommissioning), or at the designated hourly change interval, whichever is sooner. Don’t forget to periodically change transmission fluid. This lasts a long time; for the small quantity and cost, my suggestion is to do so every two years even if it fails to meet the manufacturer’s hour threshold.
Grease is a mariner’s friend. It too is used to prevent friction and corrosion. Traditional cone-style seacocks, for instance, are designed to be greased. But many will be surprised to learn that even the ball-valve seacocks that don’t require grease will benefit from it where a grease fitting can be installed by filling the cavity between the ball and body to ease movement and discourage fouling. Water-resistant marine trailer-wheel-bearing grease from Lubrimatic has served me well in this application. However, at least one metallic seacock manufacturer, Groco, offers its own proprietary grease, which includes a growth inhibitor. In cases like these, where grease comes into direct contact with seawater, the more viscous and stickier it is, the better. For this reason, avoid using light silicone, Teflon or lithium-based greases. While these have their proper uses, they are less than ideal in wet locations, where they can be more easily washed away.
Cable-over-sheave steering systems also benefit from heavier wheel-bearing-type grease, where the cables pass over the sheaves and quadrants, and for chains and sprockets and sheave axles. Water-resistant trailer-wheel-bearing grease is also well-suited to lubricating conventional rudder and shaft stuffing boxes when being repacked (some stuffing boxes even include grease cups to inject grease into the packing). You can never have too much lubrication here, and sticky grease helps hold packing in place during assembly.
Shift and throttle controls also benefit from lubrication and corrosion inhibition. Most cables are “lubed for life” and don’t require additional attention. However, levers (where they pass through binnacles) and cable terminations (at engines, transmissions and levers) will benefit from a few drops of light oil (crankcase oil can be used) once or twice a year, both for lubrication and to stem corrosion.
From left: Shift and throttle cable ends, particularly the spring-loaded variety, can suffer from both wear and corrosion; a few drops of oil or other light lubricant will keep both at bay. Steering chains and sprockets, with their many moving parts, should be periodically cleaned and greased. In order to maximize service life, cable-over-sheave steering systems require lubrication of both the cable-to-groove interface, and the sheave axle.