Exploring the World of Marine Grade Plywood: Types You Should Know

For over four decades, my experience in the boatbuilding industry has led me to a clear understanding that plywood either falls into the category of marine grade or it does not. However, many in the industry are often left questioning the diversity of marine grade plywood. The reality is that there are several types of marine grade plywood that cater to different needs within the marine construction sector. In this article, we will demystify the various types of marine grade plywood and discuss why they are crucial in marine construction.

The Basics of Marine Grade Plywood

Before we dive into the various types, it's important to understand what marine grade plywood is. Marine grade plywood is specifically designed for use in environments where long-term exposure to water, salt, and other harsh conditions is inevitable. Unlike standard plywood, marine grade plywood is manufactured to withstand these conditions. The key components of marine grade plywood include:

High-quality wood species with resistance to rot and mold Waterproof glue Special surface finishes to prevent water absorption

The durability and reliability of marine grade plywood make it a staple in boatbuilding and marine structures, ensuring that the completed project can withstand the elements for years to come.

The Various Types of Marine Grade Plywood

Now, let's explore the different types of marine grade plywood available today.

Type 1: RDF (Weather Tight) Plywood

One of the most commonly used types of marine grade plywood is RDF (Weather Tight) plywood. This type is designed for areas that are not submerged in water, such as the decks of boats and the inner surfaces of galleys and saloons.

Key Features:

Solid and stable Resistant to moisture and mildew Available in a range of thicknesses

RDF plywood is the go-to choice for creating watertight seals and ensuring that your marine construction project has a long-lasting and reliable finish.

Type 2: ST (Submersible) Plywood

ST (Submersible) plywood is designed for submerged structures, such as bulkheads, keels, and the hull of a boat. This type of marine grade plywood is made with an extra layer of protection, including a special surface finish that significantly reduces the risk of water absorption.

Key Features:

High resistance to water absorption and salt Slower swelling and shrinking More durable in wet environments

ST plywood is the ideal material for ensuring the structural integrity of submerged parts of a boat, providing a long-lasting and reliable solution in the harshest conditions.

Type 3: Marine Plywood Composite

Another type of marine grade plywood available is the composite version. This type combines the benefits of both wood and non-wood materials to create a durable and resilient finish. Some common composite materials used in marine plywood include:

Reclaimed wood Composite fibers Engineered wood products

Key Features:

High strength and durability Fire resistance Weather resistance

Marine plywood composites offer a versatile and durable solution for various marine construction projects, from decks to superstructures.

Choosing the Right Type of Marine Grade Plywood

Selecting the right type of marine grade plywood is crucial for the success of any marine construction project. Here are some factors to consider when making your choice:

Location: Determine whether the plywood will be in direct contact with water or in a dry, non-wet area. Usage: Consider whether the plywood will be used for aesthetic purposes or structural integrity. Cost: Check the cost of different types and choose the most economical option that meets your requirements. Availability: Ensure that the type of marine grade plywood you choose is readily available in your area.

By carefully considering these factors, you can select the right type of marine grade plywood to meet the needs of your marine construction project.

Conclusion

The world of marine grade plywood is more diverse than many realize. Whether you need weather tight SPF for your deck or submersible ST for your hull, the right type of marine grade plywood can make all the difference in the success of your marine construction project. Understanding the various types and their unique features can help you make informed decisions, ensuring that your project not only looks great but also performs well in the harshest of marine environments.