Acrylic latex paints have demonstrated outstanding durability in the most rugged environments including direct sunshine, moisture from rain and snow, and at the seashore. Due to the superior adhesion of acrylic latex paints, they don’t tend to blister, crack or flake when exposed to rain or high humidity. Remember that the most important part of repainting is surface preparation. While priming is usually not necessary for some repaint surfaces when using an acrylic latex paint, it’s a good idea to prime any bare wood. For the best performance in the seashore environment you describe, it’s advisable to carefully wash away any salt deposits found on the surface to be painted along with any “chalk”.