Best Oils To Protect Your Boat's Wood

Wooden boats are beautiful, but they require a lot of care and maintenance. One of the most important aspects of wooden boat upkeep is sealing and finishing the wood. There are many different ways to finish the wood on your boat, each with its own pros and cons. Some common oils used for finishing include mineral, tung, linseed, walnut, soya, and lemon oils, as well as various oil/varnish blends. These finishes can be applied by brush, cloth, or pad and will darken the wood while providing some protection from the elements. However, they will not create a high-gloss finish and will need regular reapplication. For a higher-gloss finish that lasts longer, you might consider varnish, epoxy, or even shellac.

The pros and cons of using oil on boat wood

The use of oil on boat wood has been a topic of debate among boat enthusiasts and builders for centuries. While some swear by the lustrous finish and protection that oil provides, others have reported disappointing results and challenging maintenance. Here is a detailed look at the pros and cons of using oil on boat wood:

Pros of Using Oil on Boat Wood:

• Aesthetic Appeal: Oil finishes enhance the natural beauty of wood, highlighting the grain and inviting touch. The warm and inviting look of oiled wood can be very appealing, especially for those who appreciate the unique character and emotional connection of wooden boats.
• Ease of Application: Oils such as mineral, tung, linseed, walnut, soya, and lemon are easy to apply. They can be wiped on, left for a few minutes, and then wiped off. This simplicity makes oil finishes accessible to boat owners who may not have extensive woodworking experience.
• Protection: Oils like tung oil, when applied in multiple coats, can provide a thin film that offers some protection against the elements. This is particularly beneficial for boats exposed to saltwater and sunlight, as the oil acts as a barrier, helping to prolong the life of the wood.
• Restoration and Reapplication: Oil finishes are relatively easy to restore and reapply. This is advantageous for boat owners who want to maintain the appearance and protection of their vessel's wood without undertaking a complex refinishing process.
• Flexibility: Oils allow for flexibility in the finishing process. They can be used alone or as a base coat under a more durable topcoat, such as polyurethane. This versatility enables boat owners to customize the finish according to their specific needs and preferences.

Cons of Using Oil on Boat Wood:

• High Maintenance: Oil finishes on boat wood require constant care and protection to prevent deterioration. They are susceptible to the absorption of pollutants, such as jet fuel and dirt, which can result in an unsightly appearance. Restoring oiled wood can be costly and labour-intensive, often requiring stripping the wood back to its bare state.
• Longevity: Oil finishes have shorter lifespans compared to other options. Boat owners can expect to reapply oil finishes every season or at least once a year. This frequent maintenance may be inconvenient and time-consuming for those who use their boats regularly.
• Slippery Surfaces: Oiled surfaces can become slippery, especially when exposed to water. This poses safety concerns for sailors, as a slick deck is the last thing one would want to deal with at sea.
• Time-Consuming Application: While oil application is straightforward, it can be time-consuming due to the need for multiple coats. Waiting for each coat to dry or become tacky adds to the overall time required to complete the finishing process.
• Incompatibility with Certain Woods: Some tropical hardwoods, such as cocobolo and lignum vitae, are challenging to finish properly with oil and are recommended to be left bare. This limits the options for boat builders who may prefer to use these woods for specific structural or aesthetic reasons.

How to prepare the wood before applying oil

Preparing the wood on your boat before applying oil is a crucial step to ensure the oiling process is effective and long-lasting. Here is a detailed guide on how to prepare the wood:

Step 1: Install the Wood Properly

It is essential to use dry wood with a moisture content below 18%. This is because chemical reactions between metal fasteners, water, and wood can cause problems with the finish. Use high-quality, corrosion-resistant fasteners, as corrosion accounts for about 30% of marine equipment failures. Pre-drill and countersink all screws, ensuring the angle of the screw heads matches the angle of your countersink. If joinery skills are available, consider avoiding fasteners altogether and opt for traditional joints glued with epoxy, which are often stronger.

Step 2: Sand, Clean, and Sand Again

Sanding is a critical step in preparing wood for oiling. Use a random orbit sander, starting with 80-grit sandpaper if the wood feels rough. If the wood is already smooth, you can start with 120-grit. Work your way up to 120-grit and finish with 220-grit. Some woods, such as teak, benefit from being wiped with a solvent like acetone after sanding to remove surface oils and improve finish adhesion.

Step 3: Clean the Surface

Before oiling, ensure the wood surface is clean and free of any dirt, grease, or previous finishes. For waxed finishes, use white spirit on a rag and agitate vigorously to remove. For exterior use, repair any rotten wood, and sand grey wood back to a clean, bright surface.

Step 4: Prepare the Surface with Steel Wool

Once the wood is clean and dry, use superfine-grade #0000 steel wool to prepare the surface for oiling. Rub the steel wool in the direction of the wood grain with light, even pressure. This will help create a smooth, uniform surface ready for oil application.

Now that the wood has been properly prepared, you can move on to applying the oil of your choice, following the manufacturer's instructions. Remember to allow adequate curing time, and if needed, re-apply oil to any dry areas.

Different types of oils for boat wood

There are several types of oils that can be used on boat wood, each with its own advantages and disadvantages. Here are some of the most common options:

Linseed Oil

Linseed oil is a traditional choice for treating boat wood. It is derived from flax seeds and can be applied to wood to create a protective barrier. Linseed oil has been used for centuries and is known for its ability to penetrate wood fibres, providing a natural-looking finish that is flexible and moves with the wood. However, it requires frequent reapplication as it can become dull when exposed to weather conditions.

Tung Oil

Tung oil is another popular option for boat owners. It is a natural product that provides a resilient finish and is known for its durability. Tung oil is often applied in multiple thin coats to create a protective film on the wood's surface. This type of oil finish typically lasts longer than linseed oil but still requires regular maintenance.

Teak Oil

Teak oil is specifically designed for use on teak wood, which is commonly found on boat decks and expensive yachts. It is a marketing term that refers to various oil and varnish blends, so the quality of teak oils can vary widely. While teak oil can provide protection similar to tung oil, it is important to choose a high-quality product to ensure the best results.

Mineral Oil

Mineral oil is a colourless, odourless oil that can be used to treat boat wood. It is known for its ability to protect the wood without altering its colour. Mineral oil is often used when the natural appearance of the wood is desired, but it may not provide the same level of protection as other oils.

Oil/Varnish Blends

For those seeking a more durable finish, oil/varnish blends offer a combination of oil and varnish, typically applied with a rag. These blends provide the aesthetic advantages of oil while offering greater protection. Danish oil finishes are a well-known example of this type of blend, using a mixture of tung or linseed oil with varnish.

Pine Tar or Stockholm Tar

Pine tar and Stockholm Tar are traditional wood protection methods used by boat builders. They are especially useful for waterproofing unseen wood in areas such as anchor lockers. While they effectively protect the wood, they have a strong smell and will significantly darken the wood, even when diluted.

How to apply oil to boat wood

Preparation

Before applying oil to the wood on your boat, it is important to prepare the wood properly. This includes sanding, cleaning, and sanding again. This process can be time-consuming, so it is important to be patient and not take shortcuts. Use a random orbit sander with 80-grit sandpaper if the wood feels rough. If it has already been smoothed, you can use 120-grit sandpaper. The goal is to keep the wood surface flat, so don't dig into the wood with the edge of the sander. Once you have finished sanding, clean the wood surface with compressed air or a tack cloth.

Choose the Right Oil

There are several oils that can be used for finishing boat wood, including mineral, tung, linseed, walnut, soya, and lemon oils. Tung oil is the most resilient option and provides some protection against the elements. It is important to note that "teak oil" is a marketing term and may refer to a variety of oil or oil and varnish formulations. Linseed oil was also used on the RMS Titanic, but it is worth noting that oil can create a slippery surface on boat decks.

Apply the Oil

Before applying the oil, wipe down the wood with a tack cloth. Pour a small amount of oil into a clean, dry container, then use a brush or rag to apply it to the wood, working in the direction of the grain. Apply the oil evenly, covering the entire surface. You may need to apply multiple coats, allowing each coat to soak into the wood before applying the next.

Wipe Off Excess and Let Dry

After the final coat has been applied and soaked into the wood, use a clean, dry cloth to wipe off any excess oil, wiping in the direction of the grain. Allow the oil to dry completely before using the boat, which may take several hours depending on the temperature and humidity.

Maintenance

To maintain your oiled boat wood, apply teak oil every 3 to 9 months, depending on the level of exposure to the elements. This will help protect the wood from moisture and prevent it from drying out or cracking.

Maintenance of oiled boat wood

Oiled boat wood is beautiful but requires constant care and protection. Here are some tips to maintain the quality and lustre of oiled wood on your boat:

• Preparation: Start with a smooth surface by sanding the wood in the direction of the grain. Use fine sandpaper (120- to 150-grit) and increase the grit size as needed. Avoid power sanders, except for a high-speed palm sander, to prevent scars and swirl marks. Finish sanding by hand with 220- or 240-grit paper for the best results.
• Oil Selection: Choose a top-quality furniture oil like linseed oil or tung oil, which seal the grain of the wood and harden its surface over time. Avoid teak oil or other products intended for on-deck use, as they are high in penetrating solvents and low in oils.
• Application: Liberally apply the oil with a polyfoam brush and rub it into the wood thoroughly. For the first coat, add a small amount of turpentine to increase penetration. Remove all excess oil, paying extra attention to corners and crevices, as any remaining oil will collect dirt and may stain clothes or upholstery. Allow the first coat to dry for a day or two before applying subsequent coats.
• Final Touches: After the final coat, if the surface still feels oily, give it a hard rub with a clean terrycloth dampened with turpentine. You can also apply wax or furniture polish to an oiled surface without adversely affecting future coats of oil. A carnauba paste wax will give the wood a glowing patina and protect it from grease and dirt.
• Maintenance: Oiled boat wood requires regular maintenance and reapplication. Expect to reapply oil every few months and perform regular cleaning to prevent dirt and moisture buildup, which can lead to rot.
• Consider Varnish: While oiled wood is beautiful, it requires more maintenance than varnished wood. Consider varnishing interior wood, especially if it is not teak. Varnish provides better protection against moisture and typically lasts longer than oil finishes.
• Keep it Dry: Ensure that your wooden boat stays dry, as moisture can lead to rot. Pay special attention to areas like the boat bilge, where water and ventilation can cause issues. Remove water and apply a bilge cleaner regularly.
• Clean Regularly: Consistently clean your wooden boat to prevent dirt and debris buildup, which can attract moisture and lead to rot. Use a good-quality boat cleaner that is suitable for wood surfaces.
• Protect with Paint: Consider painting or varnishing your boat to add an extra layer of protection. This will help shield the wood from moisture. However, be vigilant for cracking in the paint or varnish due to sun exposure, as this can expose the wood.

Frequently asked questions