Yacht Maintenance

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WorldYacht Maintenance

Yacht Maintenance (General)

Daily/Weekly Maintenance

Electrical and Electronics

  • Check the battery charge level, in both the engine and the house batteries. If the battery levels are low then charging circuits (battery charger, alternator, etc) will need to be engaged. Remember that leaving a lead acid battery discharged for extended periods of time damages the battery and shortens its life.


If the engine has been running then these tasks need to be done regularly.

  • Check oil level with the dipstick, top up oil if necessary. An engine can use 200mL of oil or more per hour of operation (Pallas p 86).
  • Check water level in the heat exchanger, topping up with clean/distilled water and/or radiator conditioner / antifreeze if required.
  • Check the state of the heat exchanger cap and replace it if it is broken, worn, or damaged (Pallas, p116).
  • Check water level in the salt water strainer, check to see if any dirt/debris is blocking the filter, empty the filter if necessary.

Drive Train

  • Check the oil/fluid level in the gearbox. Top up with the necessary fluid if necessary (Pallas, p90).
  • If your boat has a stuffing box, check the drop rate and temperature (Pallas, p128).
  • If your boat has a dripless (rotary, PSS) type shaft seal, then inspect the seal for any leaks (Pallas, p129).


  • Check that there is water coming out of the exhaust (nearly all marine diesels are water cooled). You need to check this every time the engine starts -- if there is no water going into the exhaust system then you have 30 seconds to shut down the engine before you melt one of the hoses, waterlocks or muffler.
  • Check the exhaust colour. Black or blue smoke in the exhaust indicates engine trouble. White smoke could mean a broken thermostat -- see below under yearly maintenance.

Monthly Maintenance


  • Flush a small dose of vinegar down the heads.

Electrical and Electronics

  • Check water levels in the batteries, if necessary then top up with distilled water (Pallas, p118).
  • Start the engine, and check the voltage level that the alternator is charging the batteries to. It should be at least 14.0 volts (and up to 14.4 volts for flooded batteries). If the battery is not being charged to this level then run through some battery/alternator/regulator tests (Calder, p93).

Quarterly Maintenance

Electrical and Electronics

  • Clean the tops of all batteries with a soft damp rag (the rag should be discarded due to the fact that it may have collected battery acid).
  • Remove the battery terminal posts and clean (Calder, p74).
  • (flooded cell batteries only) Measure the specific gravity of all battery cells and record this in the ship's log. Note that a 6 volt battery has 3 cells, a 12 volt battery has 6 cells, and a 24 volt battery has 12 cells (Calder, p79).
  • Check the belt tension on the alternator belt and adjust if necessary (Calder, p89).
  • Clean around the alternator to prevent excess dirt being sucked into the alternator coils. Also a quick spray of WD-40 or similar in and around the housing to keep things moving and keep the corrosion at bay (Calder, p 91).


  • Replace the engine oil and engine oil filters. This should be done approximately every 100 hours of engine running time (Pallas, p67). If you don't run your engine more than 30 or so hours every month then you can defer this maintenance, but it should be done at least yearly.
  • Check to see if there is any water in the primary fuel filter. This can usually be drained out using the small plug at the bottom of the filter (Pallas, p95).

Drive Train

  • Check the gearbox oil level, and top up if necessary (Pallas, p90).


Electrical and Electronics

  • Load capacity test at least the house batteries (Calder, p82).
  • Perform a preliminary test for ground current leaks by disconnecting the positive battery cable, turning off all electrical circuits including disconnecting any battery chargers and solar panels, and testing the voltage between the disconnected cable clamp and the battery post (Calder, p130).
    • Any voltage means that there is a leakage in the system. Perform a resistance test for the remaining circuit (Calder, p130), measure any leak current, and isolate any leaks (Calder p131).
  • Check over any major electrical cable runs and other ferrous surfaces to see if there are any obvious signs of corrosion. Especially check any bonding circuits on board the boat as these are places where corrosion will first be spotted (Calder, p213). If there are signs of active electrolysis or other corrosion then run a comprehensive grounding and corrosion test (Calder, p234).
  • If you have a wind generator, check the brushes, brush springs, shaft bearing, and all external fasterners. Also check the blades for wear and sand & paint if required. Rinse the housing with fresh water and lubricate any pivot points (Calder, p278).
  • Check the connection between the HF antenna tuner and the antenna itself (this is probably a backstay). The connection joints can often be a source of corrosion that will degrade the performance of your HF set (Calder, p346).


  • Change and/or clean the fuel filters (Pallas, p95).
  • Clean the fuel pump gauze if there is one (Pallas, p98).
  • Is there a camshaft belt or timing belt on your engine (overhead cam engines have these)? Then every year you need to inspect this belt for cracks. If there are signs of wear or cracks then the belt should be replaced.
  • Replace any zinc anodes on the engine, particularly on the seawater pump and elsewhere in the cooling system (Pallas, p102; Calder p375).
  • Check all drive belts (alternator, etc) and replace if necessary (Pallas, p103).
  • Check the seawater pump impeller, and replace if necessary, i.e. if there are any cracked or broken impeller vanes (Pallas p110).
  • Check the thermostat, and verify that it opens at the correct temperature. Replace it if it doesn't work (Pallas, p114).
  • If your boat has a water cooled oil cooler with a zinc anode, check this anode and replace it even if it is only partially worn (Calder p428).
  • There is a useful engine maintenance checklist on p369 of Calder. It's worth going over this at least once per year to make sure there's nothing you've missed.

Drive Train

  • Replace the gearbox oil (Pallas, p91). This is simple enough on Hurth/Newage-PRM type gearboxes that are attached to a propeller shaft and stern tube but with saildrive engines the boat needs to be hauled out to do this (Pallas, p92). Strictly speaking the gearbox oil really only needs replacing every 500 hours but this is a simple enough job and only a few litres of oil are usually required, so it doesn't hurt to do it annually. Inspect the gearbox generally for signs of water contamination, corrosion, or metal particles in the oil screen (Calder, p428).
  • If your boat has a dripless (rotary, PSS) type shaft seal, then immediately your boat is back in the water after the haulout, you must pull back the boot on the seal until water gushes out of it, this will expel any air from the stern tube (Pallas, p129).
  • If your boat has a volvo type lip seal, then you must purge and lubricate the lip seal immediately or soon after your boat is back in the water after any haulout (Pallas, p134).
  • Check the alignment of the propeller shaft (Pallas, p135) and wear in any cutless bearings on the shaft (Calder, p449).
  • Visually inspect all morse cables (push-pull cables from the throttle and gear levers in the cockpit, which run down to the throttle on the injection pump and the gearbox). Look for any signs of the cable breaking through the jacket, the jacket wearing or breaking, or corrosion. Replace the cable if in doubt.


  • Check for any blockages in the siphon break in the exhaust system (Calder p379). The valve can become blocked with salt, or wear out due to corrosion.
  • Check the exhaust hoses, connections and cable clamps (for corrosion). Especially note the condition of the injection elbow, where used water from the cooling system is injected into the exhaust gases for cooling (Calder, p377).
  • Visually inspect the hose clamps, hose, and muffler arrangements and replace any that are corroded or worn.


  • Check and grease the rudder gland.

Hull check / antifoul

  • Replace sacrificial anodes (zincs)

Less Regular -- every 2-3 years or so


  • Every 3 years, replace the timing belt (Pallas, p176).
  • If your boat has a stuffing box, every 3 years replace the stuffing box packing (Pallas, p130). You need to be hauled out for this.
  • Every 2-3 years, check, drain, and clean the cooling system (Pallas, p106 or p108, depending on the type of cooling system).
  • Every 2-3 years or 500 - 1000 hours of engine running time, check and adjust the injectors and injector timing (Pallas, p172). Consult an expert if in doubt.
  • Check and adjust the valve clearances if required. Most overhead cam engines don't require this but consult an expert if in doubt. (Pallas, p122).

Parts Lists

List of parts to have on hand at all times for your maintenance requirements:


I have three separate areas for tools on my boat. There are two drawers next to the navigation table, one marked for electrical and electronic tools (which contains things like sidecutters, wire strippers, crimp tools, etc), one marked for hardware tools (such as screwdrivers, wrenches, small saws and clamps, etc), and one longer tool cabinet which sits behind a settee berth and contains larger items such as saws, wrenches, drill and drill bits, stay cutter and axe, mitre block, etc.

Electrical and Electronics

  • Soldering iron, preferably a gas powered one with exchangeable tips (which can be used as a heat tool or hot knife as well). Don't rely on electric soldering irons on board especially at sea -- you may be repairing the connection that prevents your soldering iron from working.
  • Crimp tool (I carry two, including one that has exchangeable crimping "blades", Proskit brand).
  • Side cutters.
  • Wire strippers.

Hardware, Spares and Materials

Electrical and Electronics

  • How many times have we read a story about a boat coming into distress because their GPS failed and they carried no paper charts? Like many yachties these days I have a laptop which has a NMEA connection to the GPS and other instruments. However I have a second (USB) GPS connected to the laptop, and a spare primary GPS in a sealed plastic pack under the nav table.
  • Similarly, if there are any electronic gadgets that you can't live without then carry a spare. Especially if they are normaly located below decks or below the waterline of the boat (such as a transmitter for the hull transducer which may be located below the cabin sole).
  • Approximately 20 meters of the best grade dual core electrical cable that you can comfortably afford (tinned copper of course).
  • Solder, crimps, ring terminals, blade and/or bullet terminals, or whatever else you prefer to make electrical connections on board (some boat owners insist on soldering everything, some prefer suitably insulated crimped connections).

Engine and Engine Room

  • Oil filters. These usually screw on to the side of the engine, and you will also need a filter wrench for the purpose of removing the old one.
  • Fuel filter for the secondary (on-engine) filter, and a few spare cartridges or filter replacements for the primary filter / water separator. Depending on where you last refuelled and what the condition of your tanks is like, you may need more than just "several".
  • Plenty of rags.


Electrical and Electronics

  • Distilled water -- have at least 2 litres on hand at all times, especially if you have flooded lead acid batteries.
  • Cable ties.

Engine and Engine Room

  • Engine oil -- you will need this for top-ups as well as for oil changes. If you're not sure what sort of oil to use for your engine, check your engine maintenance manual. Pallas has a good guide to different types of engine oils commencing on page 46.
  • Hydraulic fluid for various components if required -- the hydraulic steering unit if you have one, and a hydraulic gearbox if you have one of those, although an increasing number of hydraulically operated gearboxes use engine oil instead of hydraulic fluid.



  • http://www.rememberthemilk.com/ -- a really good web site for taking care of regular reminders. Allows you to enter a simple task such as "engine service", add some notes to it, and put it on repeat such as "every 2 weeks" and "every year". Understands plain English times when you put dates on tasks such as "next tuesday" or "4th Sunday in July".
  • http://calendar.google.com/ -- the ubiquitous google calendar system, very good because it will SMS you with reminders about meetings and upcoming tasks.


  • Nigel Calder, Boatowner's Mechanical and Electrical Manual: How To Maintain, Repair, and Improve Your Boat's Essential Systems, International Marine/McGraw Hill, ISBN 0071432388
    • The book that should come as standard equipment on every boat. If you're not sure how to do something, it's probably covered in this book. I have included some references to page numbers from the (3rd, hardcover) edition of this book above.
  • Nigel Calder, Marine Diesel Engines: Maintenance, Troubleshooting, and Repair, International Marine/McGraw Hill, ISBN 0071475354
  • Don Casey, Don Casey's Complete Illustrated Sailboat Maintenance Manual, International Marine/McGraw Hill, ISBN 0071462848
  • Jean-Luc Pallas, Marine Diesel Engines Maintenance and Repair Manual, Sheridan House, ISBN 1574092367
    • I find this a useful reference and step-by-step guide for general engine maintenance tasks in a format that is sometimes easier to follow than Calder's book, although it's not as comprehensive.
  • Miner K. Brotherton & Ed Sherman, The 12-Volt Bible for Boats — 2nd Edition, International Marine/McGraw Hill, ISBN 0071392335
  • The manufacturer's manual for your engine, whatever type, make or model that should happen to be.
  • A parts catalogue for the engine you are servicing. Note that many of the parts that are regularly replaced on most diesel engines, such as oil and fuel filters, morse cables, etc, often have after-market parts that are equivalent. It's important to have a good list of these and find some local suppliers, as well as carry sufficient spares for parts that are likely to need replacing on an ocean voyage (especially in the fuel filtering area).

Also See

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