Ask SAIL: Best Anti-fouling for your Prop

I have a 2006 Najad 440 center-cockpit sloop with a 75hp Volvo saildrive. Last summer I kept the boat at a marina in Harpswell, Maine, and as the season progressed, I noticed it was slower under power. When I hauled her in the fall, the bottom was clean as a whistle (thanks to Sea Hawk AF-33 paint), but the bronze propeller blades and hub were completely covered with barnacles. I would like to put antifouling paint on the propeller. I’ve researched the topic, but have found no definitive answers as to whether it’s a good idea.
Author:
Publish date:

Nick Orem of Newbury, Massachusetts asks:

 I have a 2006 Najad 440 center-cockpit sloop with a 75hp Volvo saildrive. Last summer I kept the boat at a marina in Harpswell, Maine, and as the season progressed, I noticed it was slower under power. When I hauled her in the fall, the bottom was clean as a whistle (thanks to Sea Hawk AF-33 paint), but the bronze propeller blades and hub were completely covered with barnacles. I would like to put antifouling paint on the propeller. I’ve researched the topic, but have found no definitive answers as to whether it’s a good idea.

Don Casey replies:

If I had the definitive answer on how to keep propellers clean in seawater, I would be cruising in the south of France while my prop-coating company made fat deposits into my personal account.

DonCasey_1

You can paint a bronze prop, but not with paint that contains copper. You also have an aluminum saildrive leg, and I wonder how you keep that clean. Normally the same antifouling should be used for both the leg and prop, but if your leg has been barrier-coated, then painted with a copper paint (high-risk behavior, in my opinion), you’ll have to use a different paint on the prop. If your saildrive has a copper-free coating, you can also apply that to your bronze prop, but only after priming the bronze with an epoxy-based barrier coat.

Another popular option is to use a zinc-rich aerosol paint, such as Pettit’s Barnacle Barrier, or the similar but cheaper “cold galvanizing” sprays available at home-supply stores. This has the appeal of being simple, inexpensive and risk-free.

Instead of painting you could also try a silicone-based coating, such as Propspeed, a lanolin coating like Propshield, or a heavy wax, such as Sex Wax surfboard wax. Propspeed is highly praised, but is relatively expensive and must be carefully applied. It also depends on motion to keep props clean, so it may be less effective on a sailboat that sits idle or rarely runs under power. Propshield and similar products have a relatively short life span, not more than six months. A wax coating will last an even shorter period, but some can be reapplied underwater.

Related

albintoilet

Gear: Albin Pump Marine Toilet

Head Start Is there room for a new marine toilet? Albin Pump Marine thinks so, having just introduced its line of Swedish-built heads—ranging from compact to full-size models—to the American market. The toilets feature vitreous porcelain bowls and either wooden or thermoplastic ...read more

07n_45R2699

Multihull Sailor: Classic Cats

If you’re looking for a decent sub-40ft cruising cat, you have few choices when it comes to new-boat offerings. It is a well-known fact that the multihull market has taken off in a way very few could have predicted. Despite Hurricane Irma’s recent destruction of a large part of ...read more

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell. Got a tip? Send it to sailmail@sailmagazine.com Thanks a bunch  This scene is very calm and seamanlike. No frantic rope throwing or shouting. As he passes the line to the gent on the dock, the crew on the boat says, quietly and clearly, “Would you ...read more

mcarthy-and-mouse

Experience: McCarthy and the Mouse

Sitting at the helm in a light breeze, my arms crusted with a fine rime of salt, my skin so dry I’d lost my fingerprints, I heard a clatter and a curse from below. There were only three of us a thousand miles from shore and only one on watch at a time. Usually, the off watch lay ...read more

2018-giftGuide

2018 Holiday Gift Guide

Brass Yacht Lamp Does someone on your gift list spend the whole winter missing the warm days on the water? Let them bring a little bit of nautical atmosphere home with this new lamp from Weems & Plath. The glass enclosure means the flame cannot be blown out even by ...read more

image001

Opinion: On Not Giving Up Sailing

E.B. White was 64 when he wrote his now-famous essay “The Sea and the Wind That Blows,” which begins as a romantic paean to sailing and then drifts, as if spun around by a pessimistic eddy of thought, into a reflection on selling his boat. Does an aging sailor quit while he’s ...read more

1812-JeanneaueNewsVideo

Jeanneau Sun Odyssey 410

Designed by Marc Lombard, the Sun Odyssey 410 shares much in common with her older siblings including of course, the walk-around deck. Other features that set the 410 apart from other models being introduced this year include the 410’s “negative bow” shape allowing for a longer ...read more