Do Fiberglass Boats Sink? | Must Read


 Will fiberglass boats sink? No, modern fiberglass boats will not sink because of their architecture, design, and materials used to construct these boats. Unlike wooden boats, which were prone to cracks and holes, fiberglass boats do not have this issue.

Fiberglass boats are high in strength and durability that is why most boat makers these days prefer to make these boats. Modern fiberglass boats come with a foam core sandwiched between layers of fiberglass. Floatation foams are used to protect a boat from sinking.

All boats under twenty feet must have a foam flotation from the boat manufacturer. Polyurethane foam is used in modern fiberglass boats to prevent them from sinking. These foams are used with epoxy resins to make the fiberglass boats nearly unsinkable.

The foam adds an added layer of security to your boat in case of emergencies and helps your boat stay in the water if something bad happens.

The amount of foam needed in fiberglass boats is generally one cubic foot for sixty lbs which counts for the weight of outboard engines and deck capacity. One thing to keep in mind is these foams are highly combustible but something we should not worry about as these foams are never directly exposed to the outer layer of the boat.

Fiberglass having a low specific gravity also makes it safer as a material to be used for boats. The property of fiberglass to mold easily and make a superior hull design is what makes these boats a favorite among boat manufacturers and boat buyers.

The fiberglass boat hull is about 1.5 to 2.0 inches thick. E-Glass was the most commonly used fiberglass type for making fiberglass boats. The E-Glass is a very highly moldable substance that accounts for superior hull integrity and aerodynamic construction.

Very recently S-glass polyester is being used to manufacture new fiberglass boats. A layer of gel coat is used in these boats to harden the outer surface of the boat. The layer of gel coat also protects the exposed fiberglass sections in these boats.

Another factor accounting for fiberglass boats being nearly unsinkable is the flat bottom hull. This design accounts for the stability of the boat and makes them a very secure option. Being constructed with basically hollow fiberglass and the flat bottom hull makes these boats unsinkable. One is always advised to wear lifejackets when one is on these boats. However, fiberglass boats with the existing wooden structure are vulnerable to water rots and water incursion.

 Old fiberglass boats need special attention. They need to be washed, waxed and the stuck debris should always be cleaned so that the outer layer is safe from scrubs and intrusions of dampness and moisture.

Penetration of UV rays causes blisters in the gel coat and results in structural damage to the boat. Make sure to take care of your boat so that it lasts for decades and you are not worried about your boat sinking.

How to Deal with Spider Web Cracks on The Gel Coat?

Spider web cracks appear over time on your fiberglass boats. This indicates a serious hull inspection. After taking care of the hull issue, you must sand the spider cracks thoroughly and then reapply the gel coat. Though it is a hard job to get back the original look in most cases should work.

How Do You Know if My Fiberglass Hull Is Bad?

For new boats or older fiberglass boats, one should always check for wear and tear on your boat. Make sure you make maintenance regularly. Choppy waters can often make the hull bad of your fiberglass boats. Small repairs should make it again fine for your next ride. One is always advised against going in the water with a bad hull. Check your hull integrity regularly.

What Is the Life Expectancy of A Fiberglass Boat Hull?

A well-maintained fiberglass boat combined with periodic check-ups and maintenance, you can expect the hull to last 30 years. The advantage of having a fiberglass boat is being corrosion-free. Even if you are at sea for long hours. Always make sure you always check for marine growths like algae and other common variants of those. If you take these considerations in mind expect your fiberglass boat hull to last 30 years and beyond.

Can a Fiberglass Boat Hull Be Repaired?

Yes, the fiberglass hull can be repaired easily either with a DIY kit or with the help of a professional. Make sure you always have an emergency repair kit on your boat so that small holes and problems can be dealt with during emergencies.

Make yourself familiar with all the problems that can come on board and be ready to deal with them. If, your fiberglass boat hits something hard underneath make sure you have some sort of heavy-duty trap ready on your boat so that the situation can be dealt with accordingly.

What Happens to Old Fibreglass Boats?

Many people cut their fiberglass boats and dump them in a landfill. This practice is really bad for the environment as the fiberglass is non-biodegradable the pieces of fiberglass stays in the soil and increase the soil toxicity.

Some people have a weird idea of burning their fiberglass and in some states, this is a punishable offense. Some people let the old fiberglass boats sit on the lakes and rivers. Environmentalists are raising issues about aquatic health issues for this reason. These practices should always be avoided at all costs.

The best-case scenario is to resell your old boat to someone who needs it. It is also easy to find some old salvage yards that might be interested in your old fiberglass boat. If you have enough space in your backyard you can even turn your vintage fiberglass boats into a small playhouse for your kids or convert them into your typical outdoor kitchen the possibilities are endless.


It is nearly impossible for your fiberglass boat to sink. The foam added to your boat aids in making these boats excellent. Make sure you do periodic checks on your boat so that it remains in floating condition. Always do timely repairs on your boat to save you from big-time problems. It is also advisable not to dump your fiberglass boat rather turn it into something creative.