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There are less maintenance tasks to carry out on a saildrive transmission than on a traditional inboard shaft drive system with its associated stern gear. For example, you don’t have to worry about engine alignment, cutless bearings and stern glands. I owned a boat for seven years that had a Volvo Penta saildrive transmission system and this caused no problems during my ownership. The same applies to Yanmar saildrive systems.

However, there are a few critical things that require maintenance. These are as recommended in detail by the engine manufacturers and should be adhered to.

Corrosion

  • Drive leg housings are made from aluminium and they must therefore be well protected from corrosion, requiring a special copper-free antifouling paint, plus undercoats. The housings also need dedicated sacrificial zinc anodes to prevent them from galvanic corrosion.
  • Carefully inspect the drive leg for any damage to the paintwork. Any exposed aluminium will quickly corrode in salt water. Look for any white corrosion beginning to form on places where paint may have been chipped off. If any such damage is found it will need to be ground back before the unit becomes seriously damaged.
  • Anodes are designed to protect saildrives from electric currents generated while in sea water.
  • The electrical system of the engine will need to be an isolated system and not one which is grounded to the battery negative.
  • When a non-aluminium propeller is fitted, additional anodes are required.

Oil change

  • Regular checks of saildrive transmission oil are important. Any signs of milky coloured oil indicate water has found its way into the system. This could occur because of a shaft seal failure or defective drain plug seal.
  • Manufacturers usually recommend that the transmission oil is changed annually, which can only be done ashore by draining the oil from the base of the leg. On some systems the oil can be removed using a hand pump operated from the engine bay. In order for the oil to drain completely, remove the filler cap on top to allow air in.
  • Always use the manufacturer’s recommend oil and be careful not to overfill the system.
  • Be aware that some manufacturers recommend a torque setting for the oil drain plug and also advise that the seal is replaced regularly, because if there is the smallest crack in the rubber seal it will leak.

seal saildrive maintenance

Rubber seal

  • The saildrive leg passes through a thick rubber seal that attaches to the base of the hull. Yanmar sail drives differ from Volvo Penta so it is worth checking with the manufacturer’s recommendations. Volvo recommending replacing seals after 7 years while Yanmar recommend replacing their sail drive seals every two years, which is quite a difference. Replacing sail drive seals is a fairly major job which has to be done ashore and entails lifting the engine. The part itself is pricey but significant additional cost needs to be factored in for the engine lift and labour involved.

Learn ColRegs: Traffic Separation Schemes

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Docking a Motorboat

Docking a motorboat can be a challenging task, especially for beginners, but with practice and attention to detail, it becomes much easier. Here’s a step-by-step guide to help you dock your motorboat safely and efficiently.

How to use tides and currents to your advantage

If you are contemplating a cruise through tidal waters and strong currents, then planning your trip carefully in advance is essential to enable you to take advantage of favourable tides rather than constantly fighting against them.

Boat electrics

All boat owners should have a basic knowledge of electrics, both to avoid encountering electrical problems at sea and to stand a chance of solving them should they occur.

How a propeller works

Have a look around any boatyard and you will notice quite a variety of propellers – some have two blades, some have three and others have four or more. While most propellers are completely rigid some have blades that fold.

Weather forecasting resources and tips

All competent sailors need to have a good basic understanding of how to interpret a weather forecast. They also need to be able to interpret the actual conditions they are experiencing.

Estimating your position at sea

Navigators use a combination of techniques to estimate their position at sea. The primary method used today is GPS (Global Positioning System), a network of 24 satellites that became fully operational in the 1990s and was originally restricted for use by the United States military.

Boat maintenance below decks

While most interior maintenance work can be done when a boat is afloat, some jobs such as servicing the seacocks have to be done ashore. It makes sense to do any major interior repairs and improvements with the boat hauled out in the boatyard.

Avoiding collisions at sea – how to stay safe on the water

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Essential boat engine checklist

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Boat surveys

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Estimating and plotting your position at sea

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Antifouling for leisure boats – Part 3

Antifouling is one of the least pleasant boat maintenance jobs to do, but it has to be done. The very worst job of all is removing the old antifouling as this can get seriously messy and is very hard work.

Cleaning & polishing painted topsides

The gelcoat topsides of a GRP boat can be pampered and restored to their former glory relatively easily when it is ashore. Gelcoat is only a very thin outer layer of the hull, often less than 1mm thick, so you should avoid cleaning it with highly abrasive cleaners, or an-ything that could potentially damage its surface.

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Rudders and steering systems – Part 1

Rudders and steering systems. A rudder is one of the most critical parts of a boat. Rudder failure is a common occurrence on neglected or overworked boats and a very unpleasant and potentially dangerous thing to happen when you are out at sea.

Boat maintenance log

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Boat electrics inspection checklist

With the boat ashore, here are some recommendations for carrying out a boat owner electrics inspection. Safety is always paramount so remember to do the checks with the batteries off. Wearing a head torch helps, make notes as you go and only tackle a repair if you are 100% sure you know what you are doing:

Marine diesel exhaust checks

You should inspect the exhaust system for corrosion damage regularly, especially around the injection bend. If you have noticed the engine exhaust smoking a lot during the sailing season this can also indicate a number of potential problems.

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Care of boat batteries

Boat batteries need to be kept properly charged, which means never allowing the batteries to discharge below 50 per cent of their total charge. As well as the batteries themselves, keeping a boat’s charging systems in good shape will also help to keep batteries topped up to a higher level of charge.

Understanding tides

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Boat decks and superstructure

The deck of a boat is constantly exposed to the elements and should be inspected on an annual basis. Particular attention needs to be given to the overall condition of deck fittings such as the stanchions, cleats and chainplates.