Uh oh. You know you’re in trouble when one (or more…) of these things happens:
If you have an aluminium or steel boat:
- Blisters start appearing under your paint
- Pits form on the underwater areas of your boat
- Blisters pop up in lines along sharp edges such as chines and keels
- Corrosion appears, or white calcium deposits
- Paint peels off in sheets
- Metal components literally dissolve – sometimes in days.
If you have a fibreglass boat:
- Blisters start to appear and paint starts to peel on Stern drives.
- There is pitting on your propellers and shafts.
- Zincs or anodes are disappearing faster than usual.
- Exhaust components are corroding.
What is doing this to your beloved boat?
Chances are it’s one of two processes – electrolysis, more accurately known as electrolytic corrosion, or galvanic corrosion.
Here’s a quick explainer:
This happens when an accidental, or stray, current is present, usually due to faulty wiring or a defect in the metal. These harmful currents may come from on board your boat or from the dock. They are made worse in marinas because other nearby vessels may be generating these currents. The stray current seeks to earth itself and if seawater is present, look out! Seawater acts as an electrolyte, meaning that it is an efficient conductor of electricity. That means stray currents will flow into and through it, causing corrosion in conductive metals. This is particularly noticeable in places where conductive metals are ‘shedding’ current into the sea. Or when your prop dissolves…
Think that can’t happen? To get an idea of how rapid corrosion can be, consider this:
This corrosive process occurs when two different metals touch each other with an electrolyte (such as saltwater) present. Different metals have differing electrical potential and when you put them close to each other, they will generate a very weak, corrosive current.
Prevention: watch out for the neighbours
Imagine two boats floating next to each other in the marina. Both are made of different metals and that means they are generating a weak current between each other. Weak, but strong enough to do damage over time.
Things are worse if these boats are connected to shore power and share a common earth conductor.
And don’t think you’re safe if you own a timber boat. Timber boats have metal fittings, after all.
That means you need to protect your boat.
What’s a poor boat owner to do?
There’s not much you can do about the neighbours but there’s plenty you can do to help your boat stay afloat.
Here are some common solutions that will minimise the risk of corrosion:
- Fit a sacrificial anode. These are made of chemically active metals such as zinc. They erode faster than other metals, thereby protecting them. Warning: an anode will not work when you are at risk of electrolytic corrosion from stray currents in the process of leaving metal fixtures.
- Get your vessel checked by a marine electrician and get them to fit an electrolysis blocker.
- Use marine certified electrical leads and make sure you turn off all the power when you’re not aboard.
- Don’t leave metal items lying around in your boat. It seems harmless, but it isn’t.
- Paint your boat or coat the metal so that is isolated from seawater. This includes using corrosion inhibitors.
- Use a FAB Dock.
Use a FAB Dock and rest easy
Saltwater conducts electricity, so isolating your boat from saltwater will go a long way towards protecting it. This makes FAB Dock an outstanding solution to the problem of electrolytic corrosion because a FAB Dock is designed to stop your boat from sitting in saltwater. Our patented pumping system senses the amount of water around your boat and pumps it out. This will help you keep seawater from conducting corrosive electricity from and to your hull, prop and fittings.
There are other benefits too. Installing a FAB Dock means that not only will you reduce the risk of corrosion but you won’t have to apply antifoul either.
See our blog here on why you need to ditch the anti-foul / bottom paint
Check out the FAB Dock and find out how you can protect your vessel from corrosive electrical currents.
Annapolis Boat Show 2019 – FAB Dock proves why an Inflatable dry dock will be the best investment you ever make!
We all know that FAB Docks will keep your boat clean and dry and eliminate the need to apply toxic, poisonous antifoul, but a FAB Dock will also protect your boat in other important ways. All of our customers have found how easy a FAB Dock makes berthing their boat because of the 300mm (12 inch) tubes that they have to bounce their boats into. Well, those big bouncy bumpers also protect your boat should a storm whip up in your local area.
Case in point: we recently exhibited at the Annapolis Boat Show (for the second time as we love both the show and the town) and we teamed up with a Annapolis Boat Sales to showcase one of their Key West boats in a FAB Dock. We were positioned on the outside dock at the show which was deemed the Demo Dock so that people could take these boats for test rides all day. Being the outside dock, it was also the most exposed should a north-westerly storm blow up. Which, being our luck at boat shows, it was always going to do. So on cue, a rather large storm blew in on Saturday night.
All the local people knew to remove their boats from the dock and go and hide them somewhere safer for the night, including a couple of big RIBS and other large boats and catamarans. Those out-of-towners who were already enjoying the local hospitality and had left their brand new vessels to the forces of mother nature were left to rue their decisions the next morning. It was not only a hangover that they were nursing, but thousands of dollars worth of damage. Which would have been much worse had the show organisers not managed to find our coil of rope on our stand with which to at least try and hold the remaining boats in place. Even the marina walkways did not escape unscathed with a pedestrian detour in place until one section was repaired and reattached.
The only boat that remained all night and was unscathed in the morning was the little Key West that was safely tucked away in its FAB Dock all night. We arrived the next morning (not nursing too bad a hangover) to find it and the FAB Dock safe and sound and still dry. We just wish we had a video camera running all night to film the surrounding carnage and the performance of our FAB Dock.