Story 1

To Anti-foul or not to Anti-foul... ... ...

Why the question?

Well having recently purchased our second boat, which was slightly bigger and slightly more expensive, I had a survey carried out on her to be on the safe side.

The survey came back absolutely fine, but our surveyor, Nick Vass, suggested it would be a terrible shame to ruin our splendidly clean and unblemished hull with a coat of anti-fouling.

Being fairly new to boating and not really understanding the details of the dark world of anti-foul Nick went on to explain his rational.

Anti-foul is, apparently, a fairly nasty cocktail of chemicals designed to fall off into the sea to prevent organic articles that reside in the sea clinging to the hull.

So not only does the anti-foul potentially pollute the very environment in which I get so much pleasure, but it also creates drag, and all the issues that come along with that, reduced speed and efficiency, increased fuel costs etc.

My boat is moored for seven months on the river Stour which is brackish water and then the reminder of the year on a dry stack, so Nick suggested my boat may be a suitable candidate for ultra-sonic anti-fouling.

Being a bit of a techie geek, this instantly appealed to me and having discussed the pro’s and cons of this system with Nick for quite some considerable time, it transpired that there was a local company supplying the system.

Thus I made contact with Ultrasonic Antifouling Ltd in Poole, and had even more extensive discussions with them.

They generally suggest that boats have a coat of anti-fouling before using the ultrasonic system, but this is primarily to stop staining rather than organic items attaching to the hull.

As our boat was only in the water for seven months , and whatever I coat the hull with we’ll suffer from the Stour ‘tea stain’ in Christchurch, I agreed that it was worth trying the system without a coat of the nasty polluting traditional anti-fouling.

I also opted for the mark I system as our boat is only 7 meters and I didn’t need the more expensive mark II system, so I saved myself 50%!

Being a novice to most things boating I asked if the guys at Ultrasonic could either fit the system for me or recommend a decent marine engineer that could the job for me. To my surprise they said that fitting the system was incredibly easy, all I need was a 12v supply and access to the hull somewhere near the back of the boat (this gives the leg some protection as the ultrasonic field extends beyond the hull). Having half an idea of electronics I decided that I would give it a go, with the backup plan of using the engineers at Parkstone Bay Marina if it all went wrong!

The most important thing that was impressed on me when I took delivery of the system was to ensure that the transducer made good contact with the hull as this was how the system works. It was also made clear that depending on what type of hull I had would depend on what type of fitting we’d have to use. If I had a sandwich type of hull, then I’d need and engineer to actually install the transducer as it needs to make good contact with the outer hull, but if it was a single skin I could install the transducer myself.

Luckily by looking at the sea-cocks I could tell that I had a single skin hull, if I had a sandwich construction then there would be a small cut out area in which the sea cock would sit.

The first job was the hull preparation; using a piece of 80 grit sandpaper I sanded a small area toward the rear of the boat. Again as luck would have it, there was an area of hull exposed that was easy to reach and would fit the transducer perfectly.

The transducer screws into a plastic ring, so it was this ring that needed attaching to the hull. This was a fairly simple process of scrubbing the surface of the ring to give the epoxy something to grip to, and then epoxying the ring to the hull. Obviously the whole area was cleaned with acetone to degrease everything.

I also put Vaseline in the screws of the ring to prevent any excess epoxy clogging them up, I then secured the ring with tape to avoid it slipping whilst the epoxy went off.

The next job was to get power to the system, so I went straight to the master electrical box to get a permanent 12v supply from the domestic system.

As luck would have it there was a spare blank in the master box and I decided to put a switch on the system so I could switch it off when not required, i.e. when it was on the dry stack.


I also took the opportunity to put a circuit breaker in to protect the system from surges and this fitted nicely next to the switch.

It was then a case of running the wires from the master electrical box to the control unit, not quite as easy as it sounds as the wires had to pass through several glands and past the engine block.

However after an hour or so of struggling with tight confines and extremely efficient glands I finally got the wires to the control unit. Using standard fittings I made the connection from the wires to the positive and negative wires coming from the control box.

Being one of those people that hates drilling holes in his boat I decided to attach the control box using Velcro. Velcro has come on leaps and bounds over the past few years and is now extremely strong, so it made sense to use it. It also gives me the opportunity to remove the system and take it to my next boat if I want to!

The last job was to screw the transducer into the ring attached to the hull, after giving the face plate of the transducer a coat of silicon grease (supplied with the kit), this ensures good contact with the hull.

Then the moment of truth, throw the switch and look for the green and red lights on the control box and listen out for the distinctive click, click of the transducer doing its thing.

Success, lights and clicks, now I have to wait and see if it works, I’ll have seven months before I’ll know definitively as she gets lifted from the water, but I’m quietly confident that my lovely clean, smooth hull with remain as such, albeit a bit of elbow grease may be required to remove the Christchurch tea bag staining.

Our marine surveyor was Nick Vass of Omega Yacht Services

The system was supplied by Ultrasonic Antifouling of Poole

+44 (0) 1202 606 185
Ultrasonic Antifouling Ltd,
Arena Business Centre, Holyrood Close, Poole, Dorset, BH17 7FJ
United Kingdom

How Ultrasonic Works to Prevent Growth
Here's the science....

Water borne micro-organisms and bacteria attach and multiply to the submerged hull area creating bio-film layer ‘slime’. Algae cells also attach in the same way and develop into complex marine structures known as seaweeds. This eco-system provides an ideal food source and environment for growth including colonisation of barnacles formed from juvenile cyprid larvae assessing suitable surfaces to attach on.

The Ultra system works by emitting a specific and scientifically researched low powered pulsed ultrasonic frequencies from a digital control unit, via transducers that are in direct contact with the inside of the hull. The hull acts as a sound board, carrying the sound waves, creating a microscopic environment of moving water molecules over the entire underwater profile of the hull. As a result growth is prevented as the cell structures of the algae and micro-organisms are targeted and cannot survive.

While sound waves are resonating throughout the hull form because the transducers are directly fixed to the hull inside, the stern gear (propellers, shafts and drives) are acoustically isolated from the sound within the hull, due to the seals used in their attachment. However, in the proximity of the transducer, the ultrasound signal also dissipates out into the water in an 180o arc below the hull surface. With correct positioning of transducers, the system can also help to some degree in keeping the stern gear clear, although not quite so effectively as the hull.
Not everything described as slime on a hull is bio-film.  It can consist of dead matter that is floating in the water and sticks on, it can also be dead matter from the process of the ultrasonic system.  This non-living matter is not attached, just stuck on and the movement of the hull through the water or a light brush can easily remove it.

The program of specific frequencies and harmonics scientifically designed to destroy the various fouling organisms is unique to the Ultra System Series II.


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