Boat Bottom Blues

Posted by Darrell Nicholson at 12:00AM - Comments: (2)

Photo by Ralph Naranjo
Photo by Ralph Naranjo

Cheseapeake Blasting Services begins sealing off a Pearson 36 before soda-blasting the hull to remove layers of bottom paint.

While spring usually heralds the start of boating season for most of us, for others it means facing up to long-postponed projects. If you own an older boat, that project probably might be removing the years of antifouling paint that have built up on the bottom.

In this blog post you'll find links to a number of useful articles to help guide you through this process.

When one of our contributors recently bought an Endeavour 42, he faced a common scenario. First, he wanted to make sure the bottom paint wasn’t hiding any blisters, the notorious “pox” that afflicts gelcoat on older boats. Second, he wanted a waterproof, epoxy barrier coat to keep moisture out of the hull laminate. Third, he wanted to raise the waterline slightly to prevent slime from growing on the topside when he was loaded down for cruising.

There are several possible ways to approach this project and we’ve documented them all in Practical Sailor. Some of the articles are fairly recent, others go back more than a decade, but they remain as valuable today as they were when they were first published. Although there have been some small leaps forward in the technology used to remove bottom paint, gelcoat, and outer laminate (if needed), there have been no truly revolutionary changes. Probably the most notable change over the past ten years or so is the wider selection professional companies that specialize in this sort of work. This increase in competition has helped to contain the cost.

Whether you want to hire a professional or do the work yourself, here are some articles that can help set you down the right path.

Hull Blisters: Know Thy Enemy

Estimating the Costs of DIY Paint Removal

Advice on Sodablasting Your Hull

Practical Sailor’s Favorite Antifouling Paint Removers

Tips on Removing an Old Epoxy Barrier Coat

Favorite Bottom Paints by Region

Comments (2)

This spring I had 40 years of bottom paint removed by soda blasting (Mad Max, Edgewater, FL volusiamobileblasting.com) for $865 plus about $100 of sheeting materials that I supplied. Strange Bird is 34' LOA, 11' beam, and 5.5' draft fin keel. He was done the same day and the finish required only washing prior to epoxy. I spent an extra day with a grinder detailing near the waterline, etc. and was very glad I wasn't doing the whole bottom. The full strip allowed me to see I had no blisters of concern for great peace of mind. I finished the job with 3 coats of epoxy (black, buff, haze grey, 6 gal total, $345) and 3 coats of ABC3 bottom paint (5 gal pail, $550) both from Anderson Paint, Portsmouth, VA. If you are considering a slower method don't forget yard time layup costs.

Posted by: DanoMielke | June 3, 2015 11:23 AM    Report this comment

I'm surprized that P.S. would seem to be so biased. While soda blasting is certainly an effective means by which to remove bottom paint and prepare surfaces for refinishing, sand blasting remains more cost effective ( the cost of blast media must be part of the equation ) and every bit as efficient at removing paint, rust and even barrier coat. By manipulating the blast pressure, sand blasting can be every bit as gentle or aggressive as bicarb. Wet blasting or "Dustless Blasting" eliminates the marina owner's concern regarding airborne dust. Using recycled glass medium eliminates any silicone dust concerns and, in fact, is a totally inert /harmless substance whereas "soda" is not without environmental issues. Methods and effectiveness in controlling the after mess of what is by definition a very messy job, vary by contractor. Don't be quite so quick to disregard sand blasting as an excellent means of accomplishing what is most probably the most onerous task of any boater!

Posted by: CleanGreenMarine | June 3, 2015 9:52 AM    Report this comment

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