If you’re new to boat ownership, you might need some guidelines for how to clean your vessel. As the leading aluminium boat builders NZ-wide, the team at Circa Marine has put together a guide to the fundamentals of cleaning an aluminium hull from bow to stern.
Aluminium boats are a premium choice for sailors from all walks of life. You might be fond of cruising Aotearoa’s largest rivers, tracking the coastline, or going out into the deep blue. Regardless, this style of vessel’s qualities – such as its inherent lightness, low maintenance load, and built-in strength – make it a popular choice.
Even if your boat was constructed by the top aluminium boat builders NZ has to offer, it is still a boat. Like anything exposed to the elements on a daily basis, it still needs some tender loving care to look and perform its best.
Start with a simple rinse using fresh water. This step is essential, especially after time in saltwater, which can leave behind salt crystals that speed up corrosion over time. Use a hose with a moderate spray to wash down the entire exterior of your boat, focusing on the hull, transom, and lower areas where grime tends to collect.
Next, you want to scrub anything that might have clung on through the rinse. Use a soft-bristled brush and a gentle boat soap or an aluminium-safe detergent of your choice. You’re going to want to avoid anything too abrasive. Aluminium might be tough, but harsh scrubbing or the wrong cleaner can strip away any protective coatings or leave behind scratches that invite rust.
Start at the top of the hull and work your way down in sections, rinsing as you go so the soap doesn’t dry on the surface. For non-skid areas or sections with more grip, you might need a firmer brush and a little more elbow grease. Make sure to thoroughly clean the deck, gunwales, and any seating or fixtures too, using appropriate cleaners for those materials.
If you are dry-docking, finish off by drying off your hull with a chamois to stop water spots on the paint or hull and keep the surface gleaming. If your boat’s aluminium is unpainted or bare, you might want to apply a wax to guard against the elements. This is why, as the top aluminium boat NZ builders, we work with galvanised and coated aluminium.
Any and all boats will come up against some blemishes or marks that need more than a basic wash. Leaving these issues alone encourages them to build up over time, creating some serious problems long-term that could scuttle your vessel. If these become severe, make sure to reach out for aluminium boat repair, but if the issues are minor, you might be able to resolve them with a bit of elbow grease.
If you’re experienced with boating, then you know the waterline is often where the grime really settles in. Over time, you may notice a brownish or greenish scum buildup here, especially if your boat has spent time docked or in freshwater lakes with organic matter.
To remove this, go in with a mildly acidic hull cleaner designed for aluminium boats that is designed to break down mineral and organic buildup without harming the metal underneath. We don’t recommend using bleach or chlorine-based products, as these are a bit too harsh for aluminium.
If your boat has been exposed to hard water or left to dry without proper rinsing, you might notice chalky white spots forming on the hull. These are usually calcium deposits or mineral stains.
A vinegar-and-water solution (mixed at a 1:1 ratio) can often take care of this. Spray it onto the affected area, let it sit for a few minutes, then gently scrub with a non-scratch sponge. Rinse well. For more stubborn spots, you might need a commercial water spot remover formulated for use on metals.
From your resident boat builders, a tip: avoid steel wool or aggressive scrubbing. These spots can be frustrating, but not as much as the corrosion that could take hold in the tiny crevices left behind.
Finally, aluminium doesn’t rust like steel, but it can corrode away, especially as it drifts in saltwater environments. Aluminium corrosion looks like dull, pitted spots or a white, powdery residue.
The first and most important thing to do is to find the source of the corrosion. Look for galvanic corrosion from metal-on-metal contact (like stainless steel screws on an aluminium panel). Replace the hardware with compatible materials if necessary.
Surface corrosion can form a protective layer against the sea, but you don’t want it to get really bad. To treat it, sand the spots with fine-grit sandpaper. Once it’s smooth, wash it down, dry it, and apply a protective wax.
As you can see, this is a ritual well worth investing in. Cleaning an aluminium boat is the ultimate caring act, ensuring your vessel will stick with you for years to come. So, whether you’re launching into salt spray or gliding through glassy freshwater, take pride in your boat (and let that pride start with a good clean).
Circa Marine, a team of world-leading aluminium boat builders in NZ, has been upholding the tradition of crafting quality New Zealand-made boats for many years. Our in-house design and machining capabilities are second-to-none, allowing us to offer luxurious custom aluminium boats to clients from all around the world.
Experience the assurance that only a vessel crafted by sailors in the Roaring Forties can achieve. Reach out to enquire with Circa Marine today.