Boat Stringers: What Are They and Is It Time to Repair Them?

Don’t let the name fool you – boat stringers are incredibly durable (and essential to a well-operating vessel). While they might seem like a relatively small component, stringers are integral to your boat’s hull and overall structure. If one stringer is rotten, it needs to be replaced as soon as possible. 

This article explains what boat stringers are and signs they need replacing. Stay tuned to learn everything you need to know. 

What Are Stringers on a Boat? 

So, what are stringers on a boat? Well, boat stringers are frame components extending along the hull’s length. Essentially, you can think of them as the spine of the boat. 

They’re made of wood, wood that has been fiberglassed, or entirely of fiberglass. In addition, they provide necessary support for the deck, hull, and other boat components.

Why Boat Stringers Are Important

Stringers are essential to any boat. However, they are critical to fiberglass vessels. Because they function like support beams, keeping the vessel solid and stable is their job. They help distribute the boat’s weight and the pressure from crashing waves. 

When To Repair Your Boat Stringers

Boaters should monitor their boat’s stringers and routinely check for damage. While most new boat models have fiberglass stringers, wooden stringers will inevitably rot over time. 

Be on the lookout for brown spots, as this means water is weeping from the inside out. Additionally, keep your eyes peeled for soft spots on the deck or impact damage. And remember that the sooner you find the issue and make the repair, the better. 

If you’re unsure whether your fiberglass-encased wooden stringer is damaged, inspect it by drilling a small hole through the fiberglass into the wood core.

If the wood shavings from the drill bit are wet or rotten, you have a problem. If not, simply reseal the holes so water can’t penetrate the stringer in the future. 

When it comes time to replace your boat stringers, you’ll need the following equipment: 

  • New stringers (that are made of plywood or fiberglass sheets)
  • Fiberglass stringer epoxy resin
  • Plywood with a marine-grade finish (for wooden rafters)
  • Jigsaw or circular saw
  • Hammer and chisel
  • Drill or screwdriver
  • Clamps
  • Protective clothing – including gloves, goggles, and a face mask
  • Fiberglass fabric and mats (to make fiberglass stringers)
  • Tape measure
  • Composite (Fiberglass) Stringer Filler Epoxy
  • Adhesive
  • Rollers and brushes
  • Sealer

Boat Maintenance Tips

How to Replace Your Boat Stringers

Have a damaged boat stringer? Injecting epoxy into the damaged area is a quick fix. However, we generally recommend replacing the entire stringer. To do so, remove any nuts and bolts and the old or damaged stringers. Then, sand the hull and make sure that the area is clean. 

To make wooden stringers, cut marine-grade plywood to the size your boat requires. Then, apply a marine-grade bonding agent and use screws of epoxy glue to hold the components together. 

To replace fiberglass stringers:

  • Cut new fiberglass sheets to match your original stringers’ dimensions and thickness.
  • Coat them with epoxy and fasten them in the exact location as the old one.
  • Use clamps to hold them in place until the adhesive is set.

Afterward, seal any gaps between the stringers to prevent water from getting in. Then, check your boat (several times!) before venturing into the water, as this will guarantee everything is in working order. 

Can You Replace Only Part of a Boat Stringer?

While you can technically replace only part of a boat stringer, it is usually best to replace the entire thing. Because stringers are under a lot of stress on the water, replacing only part of them might not be enough to handle pounding waves or your boat’s weight. 

How Much Does It Cost to Replace Your Boat Stringer?

How much it costs to repair your boat stringer depends on the size of your boat and the construction of your stringer. Generally, boaters can expect to pay around $1,000 to replace a stringer.

However, that price increases significantly if you have to replace a stringer made of composite material or if you have a large boat. 

The Bottom Line

Replacing the stringers on a boat is not a simple job. Stringers affect how your boat floats and moves through the water, and you want to ensure that you replace them correctly. Therefore, many boaters will hire a boat mechanic or other boating professional to do the job for them. 

As experts in the boating industry, our Discover Boating team is here for all your boating maintenance needs. Head to our website’s Articles & Inspiration section for more how-to guides, trip inspiration, and nautical resources.