For many sailors who live in the northern hemisphere, it’s that time for the annual ritual of applying bottom paint before spring launch. Based on the latest update of our reader survey, many of our readers have already committed to their brand and type. However, if you are still deciding, our past studies of freshwater bottom paints and regional bottom paints offer another reminder that the most effective paint in our Florida test site might not always be the best for your circumstances or location. This year will be expanding the testing to west coast to test colder water performance and last year, we launched testing in the Chesapeake Bay to evaluate brackish water. The first-year results of Practical Sailor’s bottom paint test in brackish water were published in our February 2023 issue. We expect those results, which were from the Chesapeake Bay, will correlate well with many U.S. coastal waters, irrespective of salinity. One paint that was omitted from that test, Interlux Micron 66, has delivered consistently good performance in salt water, but it is not effective in fresh water, or waters of very low salinity.
According to our survey, in which 278 readers specified the paint they use, Interlux and Pettit continue to dominate the field, accounting for more than 3/4 the respondents. Among Interlux users, most used Micron ablative paints, with Micron 66, Micron Extra, and Micron CSC being the most popular, in that order. Interlux’s VC-17 was the clear favorite among freshwater-friendly paints (the paint is also popular among racers).
Among Pettit users, Pettit Trinidad, Hydrocoat, and Vivid were the most popular. Nearly 2/3 of the respondents kept their boat in the water year-round, and approximately the same number of people said they had their bottom scrubbed regularly (or did it themselves), so it was no surprise that Pettit’s popular Trinidad hard paint was a favorite. Hard paints generally hold up to scrubbing better, especially if the person doing the job does not abide by our “Bottom Scrub Tips to Live By.” Two-thirds of the Pettit users had either Trinidad or Trinidad SR (slime-resistent). The remainder was roughly split between Pettit Vivid, and water-based Pettit Hydrocoat, and a handful of the brand’s other specialty or re-branded paints.
West Marine paints accounted for nearly 15-percent of the field, Blue Water, Total Boat, and some smaller independent brands rounded out the remainder. If you are still on the fence about which paint to use, below is a general guide that we’ve shared before regarding paint selection. This combined with our report on regional bottom paints should point you in the right direction.
Choosing a Bottom Paint
Unless you’re prepared for more prep work than a light sanding, the first step in selecting a bottom paint is finding one that’s compatible with what’s on your hull now. All of the manufacturers in our test will provide guidance on this, either over the phone or on the company’s online compatibility tables. Here’s the Interlux bottom paint compatibility chart. Here’s the Pettit Paint bottom paint color chart and compatibility chart.
If you don’t know what you have on the bottom, contact the manufacturer for help. They will often recommend an aggressive sand (80-grit sandpaper) and a tie-coat, which also can provide a good foundation if you have to strip off all your bottom paint. If you are doing the work yourself, be sure to follow our boatyard safety tips, and take every precaution to avoid breathing any dust (our DIY vacuum sander can help with that), or getting the bottom paint residue on your skin.
Generally, you can repaint a hard paint with either a hard or soft paint, while a soft ablative paint will need more sanding or a tie-coat primer when being coated with a hard paint. Bare fiberglass or metal will require a primer, and aluminum components like saildrives need a special copper-free paint that won’t induce potentially disastrous galvanic corrosion.
Before plunking down more than $300 a gallon, consider where your priorities lie. It is also a good idea to talk with the local boatyard — assuming they apply more than just a few paints. Since they see the boats coming out each season, yard owners often know what works. If you are a seasonal boater who hauls out every year, you can save money by purchasing a less potent paint and re-applying each year.
Simple application: With no unpleasant solvents, water-based paints are easy and safe to apply.
The environment: Driven by legislation regulating copper loading in sensitive waters, this is a fast-growing field. In recent tests the copper-free blends from Epaint have proven the most effective in marine environments. This is good news for owners of aluminum boats, which are incompatible with most copper-laced paints. Freshwater boats will be pleased with some of the less expensive paints featured in this months report.
No paint buildup: Over time, ablative paints wear away; hard paints generally form thick layer cakes.
Quick recoating: Hard paints can take a second coat sooner than ablatives, although some of the newer copolymer ablatives can be recoated after four hours or less. Thin-film Teflon paints for racing boats can dry in a matter of minutes.
Haulout schedules: Some paints (typically hard paints) lose their effectiveness if not launched within a certain time frame, or if the boat is hauled out and then relaunched without painting. Some paints you need to lightly sand or scuff to reactivate before relaunching.
Trailerability: Some ablative paints are designed to resist abrasion from trailering. Most hard paints will trailer well, but not all are meant to dry out.
Color: Pettit Vivid, Interlux Trilux, and Blue Water Kolor offer broad palette choices. Typically, the low-copper paints (Epaint being an exception) offer more color choices. If potency is what you’re after, some makers suggest black, although our panel studies are inconclusive regarding this. Some brands (such as Pettit) put a little more copper in some of their red paints.
If you have some specific information to share about bottom paint performance in your home waters, please don’t hesitate to share it in the comments section below. If you are contemplating a complete cosmetic overhaul, our new ebook “Painting Your Boat from Bottom to Top,” covers everything you need to know about the selection, use, and application of bottom paint, topiside paint, and non-skid.
Our boat stays year round in a river off zone 2 of the Chesapeake Bay- freshish/brackish water. We usually re-do the bottom every other spring with ablative paint. Some years are worse than others for soft/slime and for barnacles. Some locations within the zone seem to be worse than others for barnacle growth. There are so many variables in conditions that it’s difficult to determine if any one bottom paint is “better” than another. So, price is the primary concern. It’s hard to believe that a $280 paint will work better than one costing $100 less considering it’ll come out every two years.
Under what circumstances will removing bottom paint result in a new barrier paint being required? Under my brown Micron Extra, I see some blue and some white layers and wondering if removing the bottom paint with chemical stripping or sanding will damage the barrier paint forcing a complete bottom job?
Are detailed test results for 2021 available for subscribers? I can’t find any evidence they are.
No ship log from previous owner. How does one learn what type of paint exists on bottom so that compatibility may be confirmed?