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10 things to consider when antifouling your boat

Friday, 08 December 2017

10 things to consider when antifouling your boat

One of four new downloadable eBooks, 10 things to consider when antifouling your boat, was created by Darren Vaux, Director of Empire Marina.

Darren has a wealth of marine industry experience and knowledge as Chairman of the Maritime Advisory Council in New South Wales, Director of the Boating Industry Association, founding Chairman of the Boating Industries Alliance Australia and Vice Chair of the Marina Industries Association.

Your guide to getting the most out of your annual lift & clean.

It’s that time again?

It seems that the time for annual anti-foul comes around quicker each year and it is tempting to delay or put off the lift to see if you can get a bit more out of it, however, there are a range of factors worth considering in this decision. The purpose of this ebook is to provide some guidance as to the key factors to be considered in making your lift and anti- foul decision.

Antifoul is required to the hulls of vessels that are stored in the water to reduce the build-up of biofouling, that is, the build-up of marine plant and animal life that seeks to make a habitat on the bottom of your boat and running gear. There are essentially two types of biofouling, microfouling and macrofouling. Microfouling is microscopic organisms like slime and algeas. Macrofouling is seaweeds, barnacles and other sea life. The type of biofouling you experience on your hull is depended on your storage location and the salinity/brackishness of your water. The rate of growth is usually a factor of water temperature. The build-up of biofouling on the hull, running gear and propellers can make an enormous difference to your speed and fuel economy. On planing boats light levels of fouling can significantly reduce top speeds and increase fuel consumption by more than 25%.

Your annual lift and clean is more than just for antifoul. It is the perfect time to inspect and replace anodes, check the hull for damage or osmosis, check through hull fittings and inspect running gear, propellers and stern bearings. All of these are important checks and the failure to keep on top of these can result in costly repairs or failures.

So let’s look at the 10 things to consider when considering to antifoul your boat.

1. Slipway or MSC?
The two most common methods employed by marinas for hauling out boats are slipways or Marine Straddle Carriers (MSCs). There are others like ship-lifts and trailers but as these are less common so we will limit the discussion to the first two.

Slipways haul boats out in cradles that run on rails where the works are undertaken on the vessel while it remains in the cradle. Slipways are the ‘old’ method for hauling out
boats. New facilities are unlikely to be built with a slipway due to the difficulties in achieving environmental and OH&S compliance and the restrictions and limitations they place on the work that can be done. Slipways also impose point loads on the hull and keel and during haul out concentrate the load on the stern of the keel and introduce twist as the rails roll over the ‘hill’ to the working platform. The undersides of keels are impossible to paint and in timber boats leaving them exposed to worm and rot. By their nature debris and contaminants from work performed on slipways is difficult to capture and contain and risks contamination the waterway. Catch drains can be inundated by seawater and sediment and become ineffective. As such, it is very difficult to achieve environmental containment when operating a slipway that doesn't haul vessels a significant distance above the high water mark.

Marine Straddle Carriers lift boats out of the water using large straps and the boat can then be ‘stood’ on a hardstand for short or long term work. The underside of the vessel is accessible and work on one vessel does not restrict the retrieval and return of other vessels. The straps lift the vessel at the strong points of the vessel at the waterline level and keel. Once stood, the keel and hull are supported on blocks and stands that follow the shape of the vessel.  When placed on a hardstand that has the appropriate containment, all biofouling, water, paint, dust and other contaminants can be recovered and disposed of and do not return to the waterway. So when you use a facility with an MSC and a full containment hardstand you are supporting the protection of the environment and our precious waterways.

2. How does Antifoul work?
Antifoul paints rely on the use of biocides within the paint that leach out over time limiting the build-up of biofouling. The typical biocide in anti-fouling paints is compounds of copper that deter the growth of biofouling. The active biocides are held in the inert resin paint matrix and leach out over time. Depending on the type of paint, the surface wears away or degrades exposing fresh paint and biocide to continue the cycle. Antifoul paints work best when boats are used as the flow of water over the hull and running gear washes away slime and other growth and exposes the clean surface of the antifoul paint to do its job.

3. Roller or Spray Application?
Antifoul paint can be applied by brush, roller or spray. Spray application achieves the most consistent paint thickness and bond consistent with manufacturers recommendations and provides a smoother lower friction surface that delivers better fuel economy and antifoul longevity.

4. Hard or Ablative Antifoul?
Its ultimately a matter of preference and usage profile when choosing ablative antifouling or hard antifouling. Both have their place and limitations, peculiar to each, but both really only offer the same 12 month service life under normal conditions.

Ablative antifoul is softer and self ablates as the boat moves through the water as well as while sitting in her marina berth. The formulation of the paint allows the paint to continually ablate exposing fresh layers of biocide maintaining effective antifoul protection.

Hard antifouling can stand some scrubbing with a soft brush to remove the slime bacteria which precedes weed and mussel growth. The practice of having divers clean your boat in the water can keep the underwater surface clean, however the associated removal of antifoul and "clouding" in the water is a source of pollution of our waterways may violate pollution regulations.

Hard antifouling will typically provide a service life of between 10-12 months, if the boat is used regularly. If the boat is not used regularly, we find with hard antifouls the boat will be excessively fouled within 8-10 months.

As most boats tend to spend a significant portion of the year on their mooring or in their pen and not moving through the water, we observe that ablative antifouling, with its slow but continual exposure of biocide, does a better job of delaying the onset of growth for boats that are perhaps only used once a month, or less.

5. One Coat or two?
Manufacturers recommendations vary depending on the paint but most specify a recommended paint thickness which can be best applied with spray application as discussed above. When surfaces are exposed to wear, for example the leading edges and waterline, a second coat is warranted. Thicknesses in excess of those set out by the manufacturer are not recommended as they are more likely to flake or fail and will hasten the need for removal of all anti-foul layers back to the hull which is required once the original bond begins to fail as shown in the photo above.

6. Keep up with your anodes.
A functional anode system is essential for every in-water stored boat as it protects your valuable running gear and propellors from corrosion. Anodes prevent galvanic corrosion of component metals by introducing a third metal into the ‘circuit’ that is more willing to give up electrons. That is, it is a more active metal, and therefore corrodes instead of the boat components. These are called sacrificial anodes and are typically zinc or aluminium.

An example, two dissimilar metals immersed in salt water create a galvanic cell, like a battery. For boats a less noble metal like a bronze propeller (anode) and a more noble metal like a stainless steel shaft (cathode) will create a circuit where the anode (or propeller) corrodes. Introduce a less noble metal again like zinc or aluminium and this will become the anode and sacrificially corrode.

Anode protection is a complex issue and you should consult a specialist marine electrician if you think you have corrosion issues. It is important to have the right amount of anodes and too many can be as bad as too little. It is also important that all of the affected components are bonded into a circuit so that the protection system works.

So, simply put, if anodes are not replaced regularly and appropriately, severe damage can occur to your running gear and propellers without you being aware of it and as such delaying your annual lift can be a false economy.

7. What about Propspeed?
Propspeed is the proprietary name for a foul release coating system designed to prevent biofouling from bonding to metal surfaces like running gear and propellers below the waterline on boats. The system is a two component system made up of an etch primer which bonds to the metal surface and a clear coat that provides the smooth outer layer. Together they provide a long lasting coating system that works best, like all anti-foul systems, when the vessels are being used. It is also important that the anode protection system be working functionally as corrosion of the running gear may displace the Propspeed.

Antifoul paints are not ideal on propellers and running gear as the bonding systems do not withstand the pressures of use and as a consequence, if vessels are not used frequently propellers and running gear can become fouled significantly reducing their effectiveness. Even when new, Propspeed provides a smoother propeller surface and efficiency than normal antifoul paint.

Our own long term study on a Selene 66 that compared the propeller coated with antifoul paint and then with Propspeed demonstrated an 18% reduction in fuel consumption at constant Engine RPM and cruising speed of 9.5kts, so Propspeed is a product worth the investment.

8. Care for your stern drive.
Stern Drive manufacturers recommend inspection and servicing at 6 month intervals, and it is highly recommend that you adhere to the manufacturer's advice as with regular maintenance these drives provide efficient and effective service but without maintenance can lead to expensive maintenance and repair consequences.

Stern drives have many moving parts. The antifouling will always crack at these locations and  growth can  spread to the leg as a whole quite quickly. The "bellows" is a flexible rubber boot which moves with the trim of the ‘leg’ and there is a tendency for sharp barnacles & mussels to grow on the bellows. If not cleaned regularly, these can actually cut the rubber when the stern drive is trimmed up or down allowing water into the gimbal bearing where it can expose the bearing to rust and seizure. When the stern drive is in operation at planing speeds, the body of the unit is actually out of the water and can become quite warm, even at normal operating temperature. This heating of the stern drive and the rapid cooling when off the plane and immersed in the cooler sea water can also affect the qualities and the effectiveness of the antifoul.

Stern Drives are also predominantly made from aluminium. Aluminium is prone to galvanic action when constantly immersed in salt water. (It is often used as an anode material) To minimise the risk of this form of corrosion, the anodes on the leg should be inspected and replaced as required at 6 monthly intervals. Stern Drives should also be left trimmed "down" when not in use to avoid barnacles growing on the trim rams, which should not be antifouled as this will interfere with their operation.

Another point to note is that the salt water cooling intakes on stern drives are usually quite small and these can become blocked with weed and shell growth leading to overheating. The shell and weed can grow up inside the leg (not visible externally)blocking the cooling circuit which also leads to overheating.

Stern drives, or ‘legs’ are a compact and effective drive system. With appropriate care and maintenance they can provide enjoyable and trouble free boating.

9. Choosing your boatyard
There are a number of key factors that you should consider when choosing you boatyard. These are our recommended key considerations:

- Dedicated modern facilities: Has the boatyard invested in the latest modern equipment to enable it to deliver competent professional service to your boat. Most leading boatyards have marine straddle carriers and full containment sealed hardstands that provide the best possible access and working environment for the people working on your boat.

- Where is the boatyard located? Is it in a sheltered location so that whilst you boat is out of the water it isn't exposed to extreme weather or contamination of your anti- foul by flying debris or salt spray?

- Do you have to drive the boat into the slipway or MSC yourself or can the marina tow or drive your boat in for you?

- How do they clean the hull of the vessel? Do they have the latest water and air high pressure cleaning systems for the best results?

- Do they have full containment and independently accredited environmental systems for their boatyard so that they are committed to protecting the marine environment that we all rely on for our boating?

- Does the boatyard have the latest spray equipment for anti-foul application?

- Does the boatyard have experienced trades on site and a wide range of accredited contractors that can meet all of your maintenance requirements.

- Is the boatyard managed and operated by a team of professional and experienced personnel so you can seek their advice and utilise their expertise to manage the process for you?

The answer to all of these questions is yes at Empire Marina Bobbin head.

10. Empire Marina at Your Service
The Hardstand at Empire Marina Bobbin Head is a state of the art marine service facility which includes a 50t Marine Straddle Carrier, 1600m2 of hardstand area and a large refit shed capable of accommodating two large flybridge cruisers. The facility has a full containment hardstand and is certified as a level 3 Clean Marina. Employing the latest spray application technologies the marina anti-fouls over 300 boats per year and has resident shipwrights, mechanics, painters, trimmers, electricians and detailers on site as well as over 100 accredited external specialist contractors.

Your boat does not have to be berthed with us to be serviced by us. We provide complimentary weekend to weekend berthing for antifoul customers so that you can enjoy the magnificent waterways around Bobbin Head while we do the work during the week. It’s all part of our commitment to make your boat ownership experience as enjoyable as possible.

Lead by General Manager - Operations, Dean Husband, our specialist hardstand team look forward to being of service to you.

To Contact Empire Marina Bobbin Head
Bobbin Head Road,
Ku-ring-gai chase National Park Nth Turramurra NSW 2074
Ph: 02 9457 9011
Web: www.empiremarinas.com.au
email: This email address is being protected from spambots. You need JavaScript enabled to view it.

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