14 Common Problems of Fiberglass Boats | Guide

Fiberglass boats have gained in popularity over years. The durability and high performance of fiberglass boats have made them a popular choice for many boat buyers. However, as with any other material or product, there are problems that can arise when owning and using fiberglass boats. There are different issues that could affect the performance and durability of your fiberglass boat.

Here’s looking at some common problems faced by fiberglass boat owners.

Wood Rot:

Older fiberglass boats have exposed or unexposed wood in them. Wood will not stay wet for a long time and as water evaporates, the wood tends to shrink. In time, the exposed or unexposed wood begins to rot leaving holes or cracks on your boat’s surface.

If you have fiberglass boats that have some exposed wood in them, fill up those holes with epoxy resin and cover those areas using fiberglass cloth. If you have fiberglass boats that are made of wood, make sure you keep the wood wet by applying linseed oil.

Bubbles in Fiberglass:

Fiberglass tends to attract bubbles while curing if not applied correctly. A slow cure rate will allow air to be trapped inside and as a result, bubbles might pop up on your boat’s surface. This problem can also occur when the material has not been cured properly.

Hull Deformation :

With age, fiberglass tends to absorb water. This leads to the loss of rigidity of the material. As a result, your boat’s hull could deform and so will its deck.

If you have fiberglass boats that are more than 10 years old, have them inspected by an expert for possible hull deformation. You can also try adding some vinyl ester resin to your boat’s hull which can help tighten up the pores.

Hull deformity can lead to an increase in the boat’s weight and a reduction in water displacement. A deformed hull can also lead to an increase in your boat’s draft.

Problems in Stringer:

The stringer is the part of the boat that supports the fiberglass skin. It also provides rigidity to your boat’s hull and attaches it to the deck. Stringer is usually made up of balsa wood covered with fiberglass cloth on both sides.

Over years, water tends to seep through the stringer’s core resulting in an increase in weight and a reduction in water displacement. This can affect your boat’s performance and you might end up carrying excess weight around.

To solve this problem, inspect the stringer during routine maintenance or hire an expert to do it for you. You can also treat the stringer with vinyl ester resin which will tighten up the pores of the stringer.

Problems in Transom:

The transom is the part of the boat that usually holds outboard motors. It also serves as a mounting point for the cleats, rubs rails, and other hardware on your boat.

With age, water tends to seep through the transom’s core resulting in an increase in weight and a reduction in water displacement. This can affect your boat’s performance and you might end up carrying excess weight around.

To solve this problem, inspect your transom during routine maintenance or hire an expert to do it for you. You can also treat the stringer using vinyl ester resin which will tighten up the pores of the transom.

Problems in Deck:

One common complaint that some fiberglass boat owners have is that their deck tends to swell or blister after using it for some time. This problem can be attributed to the low quality of material used in making your boat’s deck. Some manufacturers use cheap resin while others use molds with rough surfaces which are likely to cause blisters.

To solve this issue, get another boat with a better quality deck. If you don’t want to change your boat’s deck, sand down the rough edges and make it smooth before applying the next coat of resin. Also, select a good quality resin when doing it yourself or hire an expert to do it for you.

Improper Repair:

Fiberglass boats that undergo repairs using fiberglass patches usually lack strength and rigidity as compared to the original material. As a result, there is a higher risk of developing cracks on your boat’s hull.

To avoid this from happening, have your fiberglass boat repaired only when the damage is really serious. Repair work should be done by experienced personnel so that they follow proper procedures. In addition to this, the repair patch must also properly match the material used for repairing the area where it has been applied and must not result in additional weight of the boat.

Wet Spots:

Fiberglass boats will always absorb water and as time goes on, they tend to become heavy. Water absorption leads to voids in your boat’s hull. If not checked, these voids can lead to mold growth which can cause serious problems if not addressed immediately. To avoid this problem, have your fiberglass boat inspected by an expert to determine the extent of the damage.

Gelcoat Problems:

Gelcoat is the outermost layer of your boat’s hull. It provides color and luster to your boat’s skin. Over time, Gelcoat chips off or peels away resulting in a dull-looking fiberglass boat.

To prevent this problem from happening, avoid using harsh chemicals on your boat’s Gelcoat as they can cause chipping. If your boat’s hull is already damaged, remove the old Gelcoat and use a new layer of Gelcoat before applying color coats on it.

Problems in Filleting:

Filleting refers to the process of forming corners or curves on fiberglass boats for better aesthetics. It also provides strength to the joints formed between fiberglass boats.

The problem with filleting is that it can be easily damaged during the installation of hardware on your boat or when you are hauling the boat onto a trailer for transportation. To avoid this damage, properly exercise caution while installing hardware and tying up your fiberglass boat to a trailer.

Remember, poorly executed repairs on your fiberglass boat can do more harm than good. To ensure that your fiberglass boat looks and performs its best always follow the manufacturer’s instructions for repairs and maintenance.


Fiberglass boats are made of composites which also include fiberglass fabrics and resins. These materials cannot be recycled like other plastic products. Recycling these materials is expensive, complicated and in most cases, the end result is not in usable condition.

This means that in case your boat becomes damaged beyond repair, you will have to get rid of it without the option to recycle its materials.

Fiberglass being non-biodegradable will end up in the landfill that is why it is important to minimize waste by properly maintaining your fiberglass boat. It’s a small price to pay for a beautiful boat you can be proud of.

In Saltwater Needs More Maintenance:

Fiberglass boats are usually used in saltwater or near the ocean where humidity is high. This increases the need to check your boat for moisture and other problems which can affect its durability.

To minimize the risk of developing problems due to exposure to saltwater, have your fiberglass boat checked regularly by a professional for any signs of corrosion. In case corrosion is found, have it repaired immediately before it spreads throughout your boat.

Less Re-Sale Value:

Over time, fiberglass boats become less valuable. This is mostly due to the fact that fibers and resins in your boat become damaged and unusable which decreases its value.

This means that even though you take good care of your boat, it will still depreciate over time making it hard for you to sell it when the time comes.

In case your boat has been damaged to an irreversible state, you can always sell it as a whole or part out to interested parties who can use its parts and materials. This way you will be able to recover at least some of the money that you have invested in your fiberglass boat.

With Age Needs More Care:

All boats require proper maintenance to perform well and last longer. Fiberglass boats are no different as they also need regular inspections and other routine work to prevent problems from developing.

The problem with fiberglass boats is that as it gets older, it requires more attention to avoid developing problems. This means that you will have lesser time for yourself because you will be busy doing routine maintenance and sometimes repairs.

Taking Care of Your Fiberglass Boat:

Fiberglass boat repairs can be expensive and time-consuming. To save both your money and time, always follow the manufacturer’s instructions on how to properly maintain your fiberglass boat.

Most manufacturers will provide you with guidelines in maintaining your fiberglass boat through documentation which you should read carefully every year. If it is not provided, talk to them directly and inquire about the best practices in caring for your boat.

Taking proper care of your boat will ensure that it will last longer without needing too many repairs and other work. This way, you can save your money for other investments while having a boat you can be proud of.


Owning a fiberglass boat can be a great experience but it comes with its own set of problems. In this article, we’ve discussed some of the most common problems that you might encounter and how to solve them. We hope that this information will help you keep your fiberglass boat in good condition for years to come.