Email Us:

24/7 (Mon-Sun) Free shipping in United States

Fiberglass Marine boats

Fiberglass explained

on September 18, 2021

Do you need to fix a crack on your boat? Not sure how to work with fiberglass?

Get all your information here.

Fiberglass Marine boats

Fiberglass explained

high performance glass mat, reinforced plastic surface

Have you ever been in a conversation where someone has talked about glass fiber and had no clue what material or types of glass they were talking about?

Do not fear, after reading this piece, this commonly used, low-cost glass wool material, fiberglass, won't be so strange to you anymore.

What is fiberglass?

Fiberglass is a low-cost woven material that is widely used to repair or make many different things; for example marine boats, bathtubs, vehicles, etc.

Fiberglass is a type of glass-reinforced plastic using glass fibers. The glass strands are randomly arranged, flattened into a sheet (this sheet is called a chopped strand mat), or woven together into a glass cloth.

fiberglas explained: reinforcement chopped woven glass wool strands mat


Fiberglass is more cost-effective and more flexible than carbon fiber, stronger than most metals by weight. Fiberglass is also non-magnetic, non-conductive, and transparent to electromagnetic radiation, and lightweight.

Fiberglass production

Unlike glass fiber reinforced and used for thermal insulation, for this material, fiberglass, to be strong, it needs to be almost entirely defect-free. This allows the fibers to reach gigapascal tensile strength. The tensile strength is important for the glass-reinforced plastic.

The manufacturing process of fiberglass is called pultrusion.

Large furnaces are used for melting the filaments, at high temperature, the materials used to manufacture glass fibers.

chopped filaments melting for tensile strength, thermal insulation

After melting, the liquid form is extruded through very small bushings, (5 - 25 micrometers for e glass and 9 micrometers for s glass). These filaments are then sized (coated) with a chemical solution, called resin.

There are many different fiberglass cloths; however, for boating, you will mainly use lightweight fiberglass fabrics or cloths, called fiberglass mats.

Fiberglass on its own is not very useful. But a glass fiber reinforced with resin needs to be combined to produce composite materials. Once the glass fiber reinforced resin combination is used, it becomes hard, durable, and waterproof.

Chemical Resin: Epoxy chemical resins Polyester chemical resins

Types of resin used with fiberglass

The type of chemical resins you use with the fiberglass depends on the kind of work you will be doing with the resin.

 Polyester resin

Polyester resin is excellent for fiberglass lay-up, for example, building a boat.

Polyester resin does not fully cure when exposed to air, making it easy to use for lay-up.

Polyester resin is a good adhesive but not as strong and not as good as epoxy resins.

Epoxy resin

Epoxy chemical resin is more expensive than polyester resin but it is much stronger.

Epoxy resin is more versatile and will bond over polyester resin. But keep in mind polyester resins will not bond over Epoxy resin.

Epoxy resin is a widely used choice for repair work; when using fiberglass, it is a very low-cost way to repair your boat.

The epoxy resin will also function as an adhesive, gluing the patch to the surface.

Are fiberglass boats good?

Fiberglass boats have more weight and have better sea-keeping abilities. They are more stable than aluminum boats, with their higher weight, fiberglass boats don’t easily get buffeted by the wind.

Fiberglass boats are very durable, and with regular maintenance and care, they can last up to 50 years.

Most people would say that fiberglass doesn’t require maintenance; that is not true; every boat type needs maintenance. The maintenance on a fiberglass boat is less than on other boats. It does not cost a lot to repair a fiberglass boat either.

carbon fiber, widely used chopped cr glass

What impacts the durability of a fiberglass boat?

Small Cracks

It is important to do a boat inspection/ assessment regularly to identify small cracks; looking for cracks can help you in the long run; if you recognize any small cracks, it is best to repair them; this way, you will avoid any complications in the future.


Fiberglass can experience fatigue; when not correctly maintained or taken care of, fiberglass can be worn down and become weak and brittle.

Water Damage

It is not very likely to happen, but very possible for a fiberglass boat to get water damage.

This type of damage will most likely occur on a thing called a hull, which is below the waterline, If by some chance there is a crack and water gets in, leaving it will mean that more water will be absorbed, and eventually the damage will apply pressure and will cause wear, blistering and cracking. This type of damage is not very common, as fiberglass with the resin is waterproof; however, if the boat is not maintained and not inspected regularly for problems, this might just happen.

Structural issues on fiberglass boats are more difficult to repair and restore; if a small problem occurs, you can patch it up; that is why it is important to regularly inspect a fiberglass boat. Wooden boats require more maintenance but parts on wooden boats are replaceable. 

If you plan to buy a used fiberglass boat, always do a proper inspection and look for any structural damage. 


Fiberglass maintenance

Fiberglass boats do not require a lot of maintenance if you compare them to non-fiberglass boats; however, this does not mean any maintenance at all!

Maintenance is vital for any and every boat! Taking care of your fiberglass boat and follow regular maintenance steps means you can enjoy your boat for many years to come.


Fiberglass boats have a gel coat layer that protects the underlying fiberglass from the sun, salt, etc.

A gel coat in good condition gives you that tough glossy exterior finish, a gel coat in poor condition will provide you with a chalky look, but you can change the chalky look with maintenance!

To maintain the gel coat, you need to wax or polish, waxing your fiberglass boat will protect and seal the gel coat from water, dirt, salt, and sun. The polish will remove boron oxide from the gel coat and make it shine. Wax your boat at least twice a year. 


3 Steps to avoid chalking, fading, and hazing due to constant exposure to sunlight.

1. Give your boat a good thorough cleaning:

Ensure your boat is clean before you start waxing, use quality fiberglass Marine products to clean your boat.

Rinse your boat with fresh water.

2. Polish your boat:

Use a protectant to buff and polish the gel coat; remember the gel-coat is a layer that protects the fiberglass and at the same time makes your boat look neat, so taking care of it will only be in your best interest. fiberglass polish marine products

3. Waxing:

Use fiberglass wax marine products to make sure your boat retains its good looks! Wax at least twice a year. 

 carbon fiber, widely used cr glass

Wash your boat fiberglass regularly.

Wash after every trip!

It is vital to rinse your boat after every boat trip removing the salt from the boat; you don’t have to use expensive cleaning products.

Wash your boat with fresh water and marine quality cleaning products used for fiberglass. These products will remove stains and will add protectants to your fiberglass boat.  Fiberglass - Marine products

Keeping your boat clean is the number one maintenance tip! After every trip, it is good to clean with marine products and rinse with fresh water, removing the salt from the boat. 

Inspect your boat regularly.

Inspecting your fiberglass boat on a regular basis will help avoid future problems; if you identify any small cracks or any work that needs repairing on the fiberglass, it is best to do it immediately, saving you from future problems and more damage. Leaving small problems or cracks that are not yet considered a problem is a mistake; leaving it means you will forget about it, and then as time goes by, the problem will become a bigger problem and cost you even more!

Use a schedule and monitor your maintenance & repair work.

This way, you can keep track of repair work that needs repairing and repair work that is complete on your fiberglass boat.

example, low cost light weigh chopped woven mat

Hopefully, after reading this blog, you understand a little more about reinforced plastic, tensile strength, fiberglass, and its high performance.

For more detailed marine maintenance, please visit. 

Marine Boat maintenance daily, weekly and monthly 

Find all the Marine Fiberglass-related products you need with just one click! 

Marine fiberglass products


Please note, comments must be approved before they are published

Are you an avid fisherman looking for ways to improve your chances of landing the...

When it comes to boating, safety should always be a top priority. Making sure you...

It’s only natural that the goal of every boating trip is to have as much...

Infinity RGB Marine Speakers Whether camping or fishing, Infinity Reference Marine Speakers are the perfect...

If you have a boat, you need a marine radio. It's the best way to...

If you're a boat owner, there are some essential items you need to make sure...

You've seen marine merchants selling a variety of gadgets and equipment for your boat, haven't...

Your safety matters! It is essential to have a beacon locator on board.

Some lakes are simply better than others, offering more fish, better fishing conditions, and more...