Prepare your diesel for the sailing season before launch day
My wife, Terrie, and I laid up our Malo 47, Nada, ashore in Spain this past August and came home to take care of other business. We will be returning to Nada toward the end of this month. All systems were working fine when we left, but it cannot be presumed this will be the case when we go back. Mechanical things need regular use and tend to seize up without it. Mechanical and electrical equipment also both suffer from the salt atmosphere invariably present along any coast.
There is always an element of trepidation when I step on board the boat after a long layup and turn on the main battery switch. Will the panel come alive, or are the batteries dead? After that, assuming the electrical system boots up as it should (and following a moment of blissful relief !) there are also a number of tests I run both before and after I’ve fired up the engine to help ensure things go well in the months to come.
A BLESSING ON YOUR ENGINE
The Holy Trinity for diesel engines is clean fuel, an unobstructed airflow through the engine and exhaust and compression levels that result in high enough air temperatures to ignite the injected diesel fuel. In what follows, I am going to assume readers have been diligent about routine maintenance. Even so, the #1 cause of problems with marine diesel engines is contaminated fuel. Over a winter layup, especially with a metal tank that is not full, there will be condensation on the tank walls that will result in a small pool of water in the base of the tank. This must be removed rather than waiting for it to be collected in the primary fuel filter.
CLEAN FUEL: On all the boats we’ve owned over the past 30 years, I have installed a pumpout line set to within an eighth of an inch of the lowest point in the tank and connected to either a 12-volt diesel fuel pump—available from any automotive store—or a manual pump rated for diesel. I always pump a sample of fuel from the base of the tank before cranking the engine at the beginning of the season, as well as after refueling and throughout the season itself. In recent years I have also added yet another line of defense again water intrusion in the form of a hygroscopic (moisture absorbing) filter on my fuel tank breather from H2Out.
In addition to water, this sampling line will also reveal the presence of any other fuel contamination that might exists. Many readers, especially those with older boats, will have seriously fouled fuel tanks. All of us are also going to be faced with an increasing potential for bacterial fouling in future as we find bio-diesel creeping into our fuel supplies.
If fouling is found, the single most important favor you can do yourself is to find a way to get into the tank and clean it up—as soon a possible! This is vital if you want a reliable diesel engine. The cleanup is typically not easy, as I know from experience after we had to do it on our own boat after taking on a batch of seriously contaminated biodiesel in Sweden. On the plus side, however, it’s less trouble than having your engine conk out when you most
need it, like when you’re clawing your way off a lee shore.
AIRFLOW: Once I’ve assured I have clean fuel, I turn my attention to the airflow through the engine on both the inlet and exhaust sides. Many small marine diesel engines have a foam air filter on the inlet side, which must be rinsed out periodically. Others have a replaceable paper element filter. On the exhaust side, because many of us run our engines under-loaded and for only short periods of time (when getting in and out of slips or picking up and setting anchors) there will often be carbon fouling. It is therefore worth breaking the exhaust hose loose every two or three years to check for this. It is OK to have a fine film of carbon on the hose wall, but there should not be any sludge or crust. If there is, you must replace the hoses and change your operating practices to increase the load on the engine when it is running. While you are at it, check all hoses for signs of softening, hardening or cracking, and the hose clamps for corrosion of screws and bands. Replace as necessary.
After that, take a close look at the exhaust elbow. This is typically the point at which cooling water is fed into the exhaust, which in turn means these elbows experience a combination of high temperatures and salt water injection. Over time, corrosion is inevitable. Some elbows remain intact for many years, while others may corrode through in as little as 3-5 years. A leaking elbow will allow potentially lethal carbon monoxide into the boat.
COOLING SYSTEM: Your engine’s raw water cooling system injects the aforementioned saltwater into the exhaust, again typically at the elbow. Check the strainer for fouling. It is also a good idea to pop the cover off the raw water pump and check the impeller for any signs of damage: notably cracking of the vanes at their base or flattening of the tips of the vanes where they rub on the pump housing. Flattening indicates considerable wear—time to install a new impeller. Especially if the boat has been laid up in a cold climate, crank the engine just enough to rotate the impeller a quarter to half a turn; sometimes the vanes that are up against the cam inside the housing will take on a permanent set, which in turn will cause them to not contact the housing beyond the cam, making them useless in terms of pumping water.
At some point in the raw water circuit there will almost certainly be a vented loop—a device that prevents sea water siphoning into the engine when it is shut down. This is a critical piece of equipment that is routinely ignored during servicing. The valve at the top of the loop must be removed and washed clean of any salt crystals. If there is a leak-off hose from the valve into the bilges, make sure there are no kinks with low spots that can hold moisture. While you’re at it, the lower end of the hose should never be below the level of bilge water, another condition that will render the vented loop ineffective.
Finally, your raw-water system may have one or more sacrificial anodes to inhibit corrosion. If present, these must be inspected and replaced if more than half consumed. Their effectiveness is directly proportional to their surface area so if you wait until they are entirely consumed before replacing them, they will not have been working properly for quite some time.
BELTS: Check the tension on any belts and look for signs of excessive wear, hardening or cracking. The generic rule of thumb for V-belts is that you should not be able to depress the center of the longest stretch of belt run more than 1/3 to 1/2in with considerable finger pressure. For serpentine belts—the type with multiple small grooves—you should not be able to twist the belt more than 90 degrees. Note that the load on a V-belt is taken by the sides of the belt. If the belt and/or pulleys have worn to the point where the belt is bottoming out in the pulley grooves, the belt needs replacing, maybe the pulleys as well.
GENERAL: Every few years, closely inspect the engine feet for excessive corrosion of the metal parts, and/or softening of the rubber inserts. Some engine manufacturers recommend replacement every five years, but in practice, so long as oil and diesel are not spilled on the rubber, they generally will last much longer than this. Finally,
clean not just the engine but the entire engine compartment. A clean engine will make any leaks obvious when it is running, enabling preventive action to be immediately taken.
BACK IN THE WATER
Once the engine has been inspected, we are ready to launch the boat. If you have a mechanical “dripless” shaft seal, as opposed to a traditional stuffing box, once the boat is in the water you should pull back the boot until some water squirts out. This will ensure there is no trapped air pocket that might cause the seal to burn up. That done, it’s time to start up the second phase of your system’s commissioning program.
BATTERY CONDITION: I am assuming you have kept your cranking battery at least near a fully-charged state during the layup. If not, and it has been partially or fully discharged, it has likely suffered significant internal loss of capacity through sulfation. This loss of capacity can often be recovered, but requires specialized charging equipment.
ENGINE OIL: Before cranking, the engine oil level needs to be checked and the freshwater side of the cooling system inspected by removing the radiator-type cap to ensure it is full. Also be sure to open the raw-water seacock. We already made sure the fuel is clean and the air flow through the engine unobstructed, so as long as we have a healthy cranking speed and good compression, we should now—in theory, at least—be able to get the necessary heat to ignite the injected diesel and our engine more-or-less has to fire.
Unfortunately, the reality is that over a long layup the oil will have drained off the cylinder walls and compression may initially be low. Especially in colder climates, we may therefore have trouble achieving ignition temperatures.
If you have glow plugs, these will provide additional heat. If not, open the throttle wide and crank. If the engine immediately fires up, you have excellent compression. If not, the engine is likely a little old and tired. Let it sit for a minute or so. The pause will allow the diesel already injected into the cylinder to dribble down onto the piston rings to improve compression as well as allow the battery to catch its breath (the initial cranking will have also warmed the cylinders). Crank again. If the engine does not fire on the second or third attempt, there is something amiss that needs to be investigated.
Is it smoking? Assuming the engine fires, check the exhaust for water flow to make sure the raw-water cooling system is functional. Look for smoke. White smoke is probably water vapor, and if so is of no concern. Blue smoke, on the other hand, comes from burning oil and should rapidly clear up as the engine warms. If it does not, the engine will likely run fine with little or no risk of a serious failure any time soon. However, further investigation is warranted. Black smoke indicates a problem with improperly burned diesel. If it only occurs on older engines during sudden acceleration it is not a problem. However, in all other cases further investigation is recommended.
CHARGING SYSTEM: Now that the engine is running we should run some tests on the charging system, which requires a quality digital multimeter. (If you don’t have one, put it at the top of your next birthday wish list.) Increase the engine speed to around 1,500 rpm; this will push the alternator to a reasonably high level of output. The single most important voltage on most sailboats is what is called the “battery absorption voltage.” To check it, set the meter in its DC volts mode and put the probes across the battery posts to which the alternator output goes. Watch this voltage. If the batteries are discharged, the voltage will climb slowly. When it stops climbing, we have reached the absorption voltage. If this is below 14.2 or 14.4 volts, you are undercharging your batteries, which will significantly impact the functionality and health of your electrical system.
If there are other batteries aboard your boat that are paralleled-in, be sure to check their absorption voltages as well. If these are lower than the primary battery, you may have voltage-robbing split-charging diodes in the system, that or voltage drop in the cables and connections. One way or another, if any absorption voltage is low, you need to find a way to correct it.
Finally, if your batteries are more than a few years old and extended cruising is part of the plan, after a top-up charge I would also run a capacity test to make sure they will remain up to snuff in the months ahead. (A description of this process will have to wait for a future article.)
All being well, the re-launch will have gone smoothly with no unexpected hiccups. Most times that we have returned to Nada after an extended layup, I have had us mechanically and electrically ready for sea in just a few hours. A day or two of putting the mainsail and headsails back on followed by provisioning, sees us set up to head offshore for another cruising season. This year we are looking forward to exploring the Atlantic coasts of Spain and Portugal. s
Vented loops also need to be checked
This impeller needs to go! Don’t neglect your engine mounts
Checking belt tension
Launch day, not later on, is the time to ensure your engine is ready for the coming season
Sampling fuel to ensure it’s water-free
Inspect the shaft seal as soon as the boat is afloat Making use of a digital multimeter
And check the oil, of course!