Beekeeping not afloat

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Actually not afloat for one week as I did my two year cycle of taking the boat out of the water to politely ask its permission to black its bottom with bitumen paint.

It’s a task I undertake every two years as a matter of good hull maintenance as it matters not one dot how nice your boat is inside or above the waterline it’s that bit of steel sitting in the water that is the most important part neglect it and you could wake up with wet feet.

So this year I have taken my boat out of the water at Harefield Marina West London on their slipway and it’s a lovely location but you are exposed to the weather and I had to endure a few days of 35*C with little or no shade and that was hard work for this typical brit but three days of rain would have been far worse to deal with.

So how this slick operation works is there is a set of railway tracks running down into the water on a gradual slope and sitting on the tracks are two sets of buggies separated by a heavy chain. You are called into the marina and position your boat alongside a pole sticking up out of the water attached to the front buggy. The marina people take over and fine adjust the position of the boat. I jump of and watch.

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The technical bit the JCB has a rope fixed to it and that goes through a couple of pulleys and then connects to the front buggy under the water. The JCB starts to reverse and the buggies start to move forward and as they move up the slope they connect with the bottom of the boat and it starts its slow climb out of the water.

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I have seen this a few times but it’s still a surprising how much of the boat is actually underwater as the boat continues to grow in front of you. The section of the boat under the water is known as the Draft and the measurement from waterline to the max height of the boat is the Air Draft.

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Eventually it’s all out of the water and secured and you are able to assess the hull and see most of it for the first time in two years.

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You always have weed growth but this time quite a few freshwater muscles, I have seen them before but this is more than usual and an indication the water I have been moving in has to be reasonably clean.

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The business end well actually the back or the correct term the stern. You can see from the photo the lower part of the boat tapers towards the prop and this tapering is known as the swim and the flat underside above is the counter. The thick bar extending out from the bottom of the boat and supporting the bottom of the rudder is known as a skeg. You may notice a slight overhang to the base plate and sides of the boat and is known as the chime and its overhanging is to allow for wear over the years. The larger chunky pieces of steel running the length of the boat are the rubbing strakes and they help protect the hull of the boat and you are happy for them to get scratched first to protect the much thinner steel hull.

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So the next job is for me is to sit back and watch someone jet washing the hull of the boat with the most powerful jet wash you can imagine a real piece of industrial kit and something out of the ark from the look of the machine and probably why this particular place does not allow you to use it yourself unlike other boat yards who are happy to let you use their jet wash but at least this way I get to stay dry. The photo does not do the power of these machines justice and just holding the nozzle steady takes reasonable strength and your arms are aching afterwards.

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So this is what you are left with everything stripped back to bare metal to approx five inches above the waterline and shows up all the scars and pitting that has accumulated over the years. The pitting on my boat is not great, it’s not the worst but it’s not great with one or two areas giving me some concern and something that may in time need attention but regular blacking and good maintenance should delay any re-plating for many years to come.

The cause of this pitting is partly down to electrolysis in the water. Very simply the water can carry a small electrical current this can be caused by shoreline boats with 240v electrics not properly earthed. Moor in a marina close to one of these boats and your hull can be in serious trouble and many a brand new boat has been irreversibly damaged in no time with no fault to the owners. Or from your own boat having poor 12v electrics and putting a charge into the water causing damage to your own boat. Finally by having three different metals in the water, bronze prop, high carbon prop shaft and a steel hull it creates a slight current similar to a battery and there’s not a great deal you can do about this one as the three metals are part of your boat .

So what happens is the electrolysis attacks the softer metal and it’s the steel hull that’s attacked as its the softer metal and starts to create pitting in the steel. So to try and prevent it we weld to the hull sacrificial anodes made of magnesium and as it’s a softer metal than the steel hull the electrolysis attacks them instead. You can see from the photo the anode on the left is almost eaten away and the other fitted two years ago has some pitting. Thankfully since I have owned the boat I have only seen electrolysis in the early years but hardly ever since and partly down to my regular blacking and the fitting of plenty anodes.

The blacking of the hull has two purposes it first protects against rust but also it insulates the hull from electrolysis. It’s important not to black the sacrificial anodes as you want them exposed. Blacking also has one other advantage your boat goes so much faster in the water for the first few months as it’s all slippery and smooth and if you wanted to a good 5mph could be possible.

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So after the hull has dried the next job is to use a grinder with heavy duty wire brush fitted and go over the hull removing any stubborn bits of old bitumen and bits of rust. Thankfully as I do my boat quite regularly this part of the job is a reasonably easy one.

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Wire brushing over its time to apply the first of three coats of the bitumen and this first coat you apply by brush working it hard into all the pits, nooks and crannies. You only apply the first and the 2nd  coat to approx six inches above the waterline and the third coat you do all of the hull to make it all look nice and shiny, well for a few months at least. You aim to apply the three coats allowing 24hours between each coat and ideally the last coat 48 hours before you go back into the water so you have the best drying times available. The 2nd and 3rd coat is applied with both brush and roller.

I am only concentrating on blacking the sides of the boat this time and only do the actual bottom of the boat every fourth year. It’s very strange but the bottom of boats just don’t degrade in the same way as the sides and it’s also extremely difficult to do the bottom of the boat given the height they are off the ground when out of the water. So what I do is alternate every two years between Hairfield, lovely location a bit exposed but lovely environment and Uxbridge Boat Yard, dirty, noisy, undercover but higher off the ground and possible to black the bottom of the boat.

A week is plenty of time to simply black the boat and it is possible to do half days and then go off and do some work but most people try to do a few extras and I opted for this approach this time. The first and most important was dealing with the topside of the counter as this is my boats achilles heel I have tackled this area a few times and the problem persists. The problem is the so called self draining decks don’t completely self drain and water runs down onto the top of the counter. This would not be a major problem if the counter then drained into the bilge and then could be pumped out of the boat. What actually happens is the water puddles on top of the counter and sits there unless I mop it up and inevitably not going to happen every time it rains. The problem is rust forms under the paint and all looks ok until one day you have a scrape around and you have big flakes of rust. This is a potential disaster as the next flake of rust could expose a pin hole in your boat below the water line. I know from my eleven years on this boat this is not a new problem and they say 7mm of rust is about 1mm of steel but how many times has this rust problem happened in the past thirty years with obvious signs of neglect before I got the boat, how thick is the remaining steel???  when the original steel thickness was only 6mm.

I have no option but to go hard at the rust out of the water and deal with any possible problems and remove all of the rust so as to treat the remaining steel and then paint over once more in the hope that the steel has sufficient thickness so that I can plan to have the hull surveyed in the future and get an accurate steel thickness and then decide if over plating is necessary.

So I attacked the rust and squeezed myself into a tight space in 30*C+ full sun chisel in hand and grinder at the ready. First hit and scrape at the loose rust flakes and then face mask and goggles start grinding and only a few seconds and it’s impossible to see what I am doing the air is thick with dust and I have to stop but keep the grinder running in the confined space to clear the rust dust. The dust clears and I target the next patch to attack and keep repeating for about six hours with breaks every 40mins to drag my poor aching body into some shade to try and cool down and drink some needed water.

Once I am happy with the grinding and confident I have removed all of the rust I can then treat the rusty surface with a chemical to try and prevent it starting again and following that two good coats of a red oxide primer followed by two coats of bilge paint. My next priority over the rest of the summer is to get to grips with the self draining channels from the back deck, get these working right and it could eliminate the rust forming on the counter top and from now on make this area a yearly maintenance priority. Since going back into the water I have been keeping a close eye on the counter tops looking for any sign of water seepage or lifting of the paint as you can imagine a leaking roof is bad news but a leaking bottom of a boat is somewhat a bigger problem but thankfully all looks dry.

looking down onto the counter top with the deck boards removed looking nice and shiny. The hole in the boat is the removed for painting the weed hatch. It's a bolted plate that can be removed so you can remove whatever has wrapped itself around your prop.

looking down onto the counter top with the deck boards removed looking nice and shiny. The hole in the boat is the removed for painting weed hatch. It’s a bolted plate that can be removed so you can remove whatever has wrapped itself around your prop.

My other extra was to repaint the back of the boat and as I painted the topside of the boat last year (missed posting about that and may catch up later) and it’s almost impossible to paint this area without getting wet so most people do it when out of the water.

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It was a hot sweaty week and the work on the back counter made it a very hard dirty week but I had the company of the ducks, moorhens, coots and mum dad and the five signets to keep me company and especially the visits from the signets made the hard days not so bad.

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So the week over and afloat once more say good bye to the signets wish them well and out onto the cut 🙂

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