Cleaning tip
Here's how to clean your fiberglass boat without harsh chemicals! All wood benefits greatly from being scrubbed with a fatty soap—we have written about that many times—but what about fiberglass boats? Today's blog is about cleaning your boat in an environmentally friendly way.
Boats are a subject all their own. There is a lot to deal with, and not everything is environmentally friendly. Over the years, both paints and cleaning products have been developed that were not at all good for the environment. Fortunately, labeling and inspections are stricter today, so you can be fairly sure that products available in stores have undergone some form of review. BUT that does not mean you should not ALWAYS read labels carefully and make environmentally responsible choices yourself.
Here are some tips on how to clean your boat in an environmentally friendly way:
The principle that like dissolves like is a good rule of thumb to keep in mind when it comes to cleaning.
Alkaline substances dissolve dirt from animals and plants, such as algae. By using a soap that is basic (alkaline), you can easily dissolve all such dirt. Much of what discolors the boat is algae, and you will notice that soap removes most of it. The soap is very gentle on the environment and readily biodegradable, but you should still be careful where you wash your boat, because you may actually be washing away things other than algae, such as oils, which are harmful to the environment.
We use Västerbottenssåpa , a superfat soap, along with three different brushes, cloth and ecofiber sponge.
Since the soap is fatty, it will also dissolve greasy dirt. All greasy oils from engines, engine compartments, etc. must be handled carefully and with caution; they are not kind to the environment, so never release the wash water directly into the lake or sea.
We also used this gigantic dish brush, actually intended for old-fashioned milk churns but perfect for boats and, in fact, hot tubs too.
We have hot water in the bucket and then “go in” with a scrub brush, a coarse one where it is heavily soiled. A soft brush where it is less dirty, and the ecofiber cloth on, for example, the seating boards.
We use an ecofiber cloth because the plastic has a textured surface that causes algae and dirt to become lodged in the uneven areas.
Before-and-after image

Yellow stripes
Acids dissolve oxides, and a pH lower than seven dissolves oxidation. When a yellowed stripe appears on a white plastic boat (e.g. gelcoat), oxidation is often the problem. Many boat owners then use oxalic acid to remove the yellow stripe/discoloration, but it can be replaced with, for example, lemon or another highly acidic fruit—this is much milder than oxalic acid. A soft drink with high acidity, such as Coca-Cola, can also be used, but the sugar must then be washed off, as it will create a sticky surface.
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Questions and answers
- Why is it important to use alkaline soap when cleaning plastic boats?
Using alkaline soap is beneficial because it effectively dissolves dirt from animals and plants, such as algae, which commonly occurs on plastic boats.
