Back in the boat: how I restore your whole hull in 7 moves

Many of us boaters can already return to our boats depending on regions and ordinances. Here’s why today.
Charles Luongo
, influencer and boat cleaning expert, tells us how to restore the hull before summer.

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How I restore your entire hull in 7 moves

Some may turn their noses up when I tell you that the first step to take is to take care of the hull first. This is true in part, since applying the new antifouling will be the last step before launching, but preparing the living work for painting is the first step since it is a process that creates a lot of dust and dirt that would literally make the work “blur” on other surfaces.

While the polishing of the broadside is something purely aesthetic (although it is not 100% so, but we will find out), Preparing the hull for launching is a primary task, in fact without this work the new paint we will apply will perform worse translating into worse performance and higher fuel consumption.

NB: Wear all necessary personal protective equipment to perform these procedures. Face mask, gloves, disposable coveralls, goggles and anything else that will preserve your health. The steps involve working with products that are toxic if inhaled, so if you are not sure, leave the work to professionals.

STEP 1: Remove what has accumulated during the previous season.

Recreational use of boats, with outings mainly on weekends and stopping during the rest of the week, inevitably leads to the accumulation of calcareous concretions and/or algae on the hull that adhere to the porosity created on the antifouling while the boat is in the water. Therefore, the first step is to remove this layer with a pressure washer.

This step has a greater yield if done in the 48 hours after hauling as you give less time for the concretions to adhere to the hull, so reading me right now it may be a job you have already done. Inevitably with the pressure washer you will remove a few spots of paint, but that is not a bad thing at all. If you have not already done so there are several products on the market to remove concretions from the hull, but be careful as they are highly acidic (pH1). Moving on.

STEP 2: Remove the old antifouling.

Antifoulings are paints designed to work “fresh.” If they dry out or dry out they lose their function. Therefore, it is important to remove the antifouling applied in the previous season to allow the new one to adhere to the hull.

When proceeding to carry out this second step we are faced with a choice: remove only the surface layer of the old antifouling or remove all layers and start again “with hull to zero.”

  • Remove only the surface layer: in this case all we need to do is to equip ourselves with a random orbital sander with disks with grits from 80 to 220 and proceed through the entire living work removing only the main dry part of the paint. We can see that it is gone since the color will be more vivid than the previous color that was oxidized.
  • Bringing hull to zero: here, however, we have different solutions depending on the fatigue and paint layers on the hull. If there are only a few layers of paint, we can repeat the previous option and go sanding with coarser grit until we get to the gelcoat. Be careful not to ruin it, so I suggest you stop when you start to see the primer of the old antifouling and use finer grit abrasive discs to avoid doing damage.

If, on the other hand, there are many layers of paint (or perhaps the boat is used and you don’t know how many there are), I suggest using a paint stripper that will wear off the paint effortlessly and allow you to remove it with a scraper without effort.


  • Solvent-based paint stripper. They are very aggressive paint strippers, acting in about 20 minutes and allowing adequate work to be done quickly. The con is that if we are not careful we will nick the bottom gelcoat and go on to damage the hull.
  • Water-based paint stripper. It is a “safe” product because it does not affect the gelcoat, but it requires longer action times than solvent-based products. Usage times vary from brand to brand, but approximately 2 hours per coat of paint. Therefore, I recommend that you apply it in the late afternoon and let it sit overnight and then proceed in the morning with paint removal.

If you choose paint remover, regardless of the type, make sure it does not dry out; the surface must remain moist and soft to allow for proper action, otherwise you will find yourself having to sand an extra layer and you will be back to square one wasting time and money. Once you have removed most of the paint proceed with sander to remove paint residue to level the surface.

STEP 3: Assess damage or problems

With the “bare” hull, it is an opportunity to check for bumps, cracks or bubbles from osmosis (you don’t know what it is? See here.) This way we can verify the actual condition of the hull and proceed accordingly to repairs before it is too late.

STEP 4: Wait

The fourth step may not be necessary depending on when you do this work. Yes, because now we move on to the steps of painting and applying antifouling. But these types of paints should be applied as close to the time of launching as possible, because AVs (antifoulings) are activated upon contact with water, and once activated if they remain out of the sea they lose their function and deteriorate unnecessarily. For this reason, there is a tendency to do the paint cycle around 48 hours before launching, otherwise there is a risk that with rain or boat washes, the paint will be activated and will perform less well during the season.

STEP 5: Apply the primer

At this point we will have our hull ready for the new antifouling cycle. Each brand has its own recommended paint cycle based on the type chosen. I recommend applying a two-component epoxy primer that offers more protection to the hull while also preventing osmosis.

Life cycle of a self-polishing antifouling.

STEP 6: Apply antifouling. Yes, but which one?

Antifouling is traditionally in three sections: self-polishing, hard matrix, and intermediate . The goal of all of them is to keep the hull as smooth as possible by preventing the formation of vegetation that would have a braking impact at the hydrodynamic level of the boat, resulting in more consumption and worse performance.

  • Self-polishing: As the name implies, this varnish tends to exfoliate during sailing so that concretions do not have time to form or in case they have formed, they go away along with the surface layer of varnish. They are suitable for displacement hulls and not too fast, as otherwise excessive water impact would take away too many layers in too short a time. Being “softer” it is easier to remove during storage. The con is that if we have stationary boats the vegetation will grow until we get back to sailing.
  • Hard matrix: Again, the name already gives an idea of how it works. The hard matrix is ideal for performance boats that stay in the water a long time. Underlying the process is the release of biocides that do not allow vegetation to grow. In this regard, paint formulations have been replaced in recent years in order to have less and less environmental impact due to the excessive release of biocides.
  • Intermediate matrix: This is what is called a “standard” antifouling by many brands. It is a compound that is somewhere between a hard matrix and a self-polishing agent. It is an economical solution that can be suitable for traditional boating in the summer period.

STEP 7: Call the carrier and launch.

As mentioned in Step 4, once painted, it is recommended to proceed with the launching as soon as possible (I know, you are also looking forward to it and already rubbing your hands at the very thought). When the boat is moved from the supports on which it rests, take the opportunity to give a few strokes of paint in those places where the hull was resting on it and thus had not been painted. Now the hull will be ready and you can sail while enjoying all the excitement your boat can give you.

Click here to see all of Carlo Luongo’s videos


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