How to Choose the Right Bottom Paint for the St. Lawrence River

Do You Even Need Bottom Paint?

It depends on how your boat lives. If it stays in the water all season — and on the St. Lawrence most do — bottom paint is your first line of defense against growth, blistering, and water intrusion. If you trailer in and out and the boat dries between trips, you may not need it. When in doubt, how long the boat sits in the water is the deciding factor.

Ablative vs. Hard Paint

The two main families of anti-fouling paint work very differently:

• Ablative paint wears away slowly like a bar of soap, exposing fresh biocide over time — good for boats that stay in and get used regularly
• Hard paint cures to a tough film that holds up to scrubbing and higher speeds, but loses effectiveness once it's out of the water for long
• The right choice depends on how often you run the boat and whether it's hauled mid-season

Barrier Coat: The Part People Skip

Bottom paint keeps growth off; a barrier coat keeps water out of the laminate. If your hull has any history of osmotic blistering — or you want to prevent it — an epoxy barrier coat goes on before the bottom paint and seals the fiberglass against moisture. It's the step that actually solves blistering long-term instead of just hiding it.

Match the Paint to How You Boat

There's no single best paint — there's a best paint for your situation. A boat in a slip all summer, a boat that gets trailered to Lake Ontario, and a boat that sits for a few years between seasons all want different treatment. Getting the prep and primer right matters as much as the paint itself; without good adhesion, even the best product peels.

Final Takeaway

Choose bottom paint based on how and where you run the boat, don't skip the barrier coat if blistering is a risk, and get the prep right. If you'd rather not guess, we'll look at your hull and how you use it and recommend a system that makes sense for the St. Lawrence.