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Tag Archive Hull

Deck Join is a Milestone

September sees Destiny start to look like a real boat! The deck finishes cooking in its mould and towards the end of the month everything is ready to be joined together. The floor section has already been installed inside the hull. The battening and cabling has been getting on well but we need the lid 🙂

Deck release

The first step is to release the deck and the upper section from the moulds. The factory do this very carefully with the use of their overhead cranes.

The upper section is full of shapes, windows and port holes. It is therefore much more difficult to produce a clean structure. There are so many more nooks and crannies to get stuck! The good thing about fibre glass is that this is not a problem as it can all be finished by hand. On close inspection I was originally shocked to see that bits of the window frame were broken. At first I went into a panic that the section would have to be made again! It turns out this is quite normal – no reason to worry. Once the experts have done their work, the fibre glass structure will be perfect.

Join the two halves

There are two sections to join. The deck section is first then the upper section goes on top. They are both turned up the right way ready to be lifted on to the hull.

Using the crane, the sections are lifted on top of the hull – and hey presto, we look like a boat!

Deck join marks a “milestone” stage in the production process. It’s now time to get the cheque book out again and transfer a sizeable number of dollars over to Jet Tern Marine. The bank account is definitely getting smaller, but the boat is getting bigger 🙂

The deck join at this stage is actually only temporary – just to show that it fits and the milestone stage is completed. The lid is quickly removed again after the photo opportunity so the factory technicians can carry on working easier inside. There are still big items to be installed in the hull before the deck can be permanently joined. We’ll catch up on all that activity when we visit the factory again next month!

Deck and infusion techniques

So we have the lower hull – but that’s only half of the boat! The next step in the manufacturing process is to laminate the upper half. This will actually be the middle deck when its finished. For those who haven’t got a clue what lamination means, this is the process of building a very strong fibre-glass shell. This can be with traditional lamination or with infusion.

The hull is now sitting in the main factory hall on a cradle with steps for access. It’s starting to look like a boat! Obviously a lot of work to go to make all the other parts.

The process starts with a mould – a bit like making jelly 🙂 The gel coat is sprayed on the mould – which is the outer layer of the boat that gives its shiny finish. After that, layers upon layers are built up gradually with glass fibre matting. This is then layered with resin, then more matting and more resin in many layers. The result is a very strong structure which is then left in the mould to cure (dry). This takes several weeks – then the structure is released from the mould and work can begin.

Each individual section of the boat has a mould. When they are made, they are stuck together and can be changed and re-modelled by hand as needed. Imperfections in the structure can easily be corrected and sections can even be completely changed.

Vacuum Infusion

For flat sections – such as the decks – where strong weight bearing is needed – a technique called vacuum infusion is sometimes used. The vacuum improves the process and results in a very strong structure. Put simply, the resin is infused at the top and dribbles into all the crevices. The vacuum sucks the resin into all the small spaces in the glass fibre matting and ensures it is completely soaked.

Deck in process of vacuum infusion

August Activities

August 2018 was about making the upper half of the boat. At the same time, the team were preparing the inside of the hull. The upper section was laminated by hand in the mould. The mould is upside down of course so its hard to work out what is what unless you know! The workers inside are spraying and laying down the layers of resin and glass fibre.

The deck and floor sections were laminated using vacuum infusion with the moulds looking a bit like a waffle. The waffle sections also add to the overall strenth of the structure.

Inside the hull, the miles of heavy duty electrical cable were being laid. The cables run through a network of conduits on each side of the boat. This will mean nothing is visible when the boat is finished. The bulk heads (interior main walls) were also being constructed. The bulkheads give the hull itself the strength – along with all the timber cross members. The lower floor was laid into the bow of the hull.

As the work continues, you can begin to see where the cabins will be. Destiny is starting to look like a boat!

Laying the Hull

As soon as the deposit was paid, Jet Tern started the build process of our new Selene straight away.  They prepared the mould for the classic Selene 60 Trawler and laminating began.  One of our key requirements has always been – no white boat!  However, this is a pretty expensive “red line” and there’s always a discussion about how best to get a coloured hull.  Do you lay it in the hull as the gel coat layer or do you paint it afterwards?  For a large boat, painting is considered the best option – and everyone recommends also that you don’t paint for the first couple of years.  It’s better to allow the FRP to settle and cure fully to avoid blistering.  Over time a gel coat layer dulls and is more difficult to maintain and repair the odd knocks and scratches that inevitably happen so painting is the way to go.

To paint or not to paint?

Jet Tern are not keen on painting at the factory.  Although an Awlgrip painted hull is one of the standard options, the huge sheds they used to do this were damaged in a storm so they are struggling to do this in the proper environment.  For this reason, as well as the general recommendation of delaying painting, they prefer clients to arrange this after delivery.  This was a bit disappointing for me.  The boat just doesn’t look the same in white but I didn’t have much choice and she would end up being blue eventually!

However, during the initial specification discussions it turned out that Jet Tern had some stock of a light grey gel coat which they could provide at no extra cost.  It’s a very light grey, so may not look much different to white in the end but we were pleased to accept this as a better interim solution.  Our current sailboat is grey – and I love that – so grey or blue are equally good in my opinion!

Laying the hull of our Selene 6043

So – they sprayed grey gel coat on the mould, followed by layers of fibre-glass and lamination.  Next, they applied a barrier coat to ensure the end quality of the gel coat and to avoid the fibre glass layers showing through.  Gradually, the lamination team built up the hull, layer by layer – and then they compress to give a thin but very strong FRP structure.  Inside, the reinforcement structure was built on top and laminated.  The end result is the strong hull that is needed for an ocean going trawler.  A “gestation” period of a few weeks followed completion of the construction and our baby lay in the mould curing – ready for the planned release when we visit in July.

An introduction to WeChat

During May and June, we got acquainted with WeChat – which seems to be how every Chinese person runs his life 🙂  It’s the Eastern equivalent of WhatsApp – and the whole factory runs using it!  Howard set up groups for the production team and the design team and we are now in touch directly with the guys on the shop floor.  Everyone has their mobile glued to them, much like we see in the West – only I think they are even more obsessed with their phones than we are.

The guys who were actually building our new Selene sent us photos almost every day throughout the initial hull laying process so we could see it come to life in real time.  We were also exchanging ideas, pictures and web sites with the design team at the same time to get together the initial specification for the interior and equipment.  Of course, we both now have yet another social media app to follow – but it’s great to wake up each morning and see the boat developing while we slept!

Looking forward to the trip to China and seeing our new Selene for real!

Anti Fouling

For the benefit of non-boating readers, anti-fouling is a special type of paint which is applied to the parts of the hull which are under the water. This is meant to stop barnacles and other growth from attaching itself to the boat. Without an effective anti-fouling system the bottom of the boat would end up encrusted with a layer of cement-like barnacles and looking like your back garden 🙂

Depending on the temperature of the water, growth happens differently. This is also dependent on how much the boat sits still and how often it moves. A boat laying in a marina for months on end is the worst and its generally necessary to dive underneath and clean the hull frequently. Anti-fouling paint normally needs renewing every 1-2 years. This is not only an expensive job, but a real hard one too! The boat has to be lifted out of the water (expensive in itself) so the whole hull can be sanded down. It is then repainted with several coats before being launched again.

CopperCoat

We have opted for a special product called CopperCoat for our anti-fouling paint. The product is very expensive to start with but it has a lifetime of at least 10 years. A much better performance than the 1-2 years expectation for normal anti-fouling paint. The manufacturer also claims to be much more environmentally friendly than traditional paints. Although the paint does contain the maximum amount of copper allowed by law, the paint does not wear off. It’s a non-ablative product. Certain anti-fouling paints are designed to “rub off” (ablate) gradually in the water which is how they work. They take the marine growth with the layers of paint. CopperCoat works differently and does not give off as many damaging products for sea life.

Copper Coat Product

We have experience of CopperCoat on our sailing yacht and over the years have done extensive research on it. The product consists of a copper powder, a resin liquid and a hardener. You also use a particular brand of thinners. The components are mixed together into paint consistency in small quantities.

Application Process

The application process and environmental conditions are critical for the success of the product. If wrongly applied, then it will not remain on the hull and will not perform is it is expected to. We’ve got experience of this too on our sailing yacht, where the initial application by the commissioning company was not done as it should have been! It can only be applied at temperatures above 8 degrees C – on a fully prepared hull. It can’t be applied in the rain or in very hot and humid temperatures.

There should be 4-5 coats applied – by roller or by spray. It is not a product which can be applied with a brush. Each coat must be applied on the “tacky” previous coat.

To apply the product properly, a team of people is ideal – so they can follow each other with the coats, working on small areas at a time.

How do you do this?

The instructions from the supplier were to use 0.5 kg of hardener and 0.5 kg of resin with 2kg of copper. This is the mix which gives the maximum copper allowed. He stressed that the hull should be sanded with 80 grit sandpaper with an orbital sander, then rinsed and allowed to dry.

A minimum of 4 coats need to be completed in 1 day using the wet on tacky method. When the first layer gets tacky you start applying the second coat. This is normally about 2 hours after you have started. This could mean you have to start the second coat before you have finished the first coat! Therefore, this is best achieved by having two teams of four people painting. An additional person is mixing the paint all the time so that the copper doesn’t sink to the bottom.

The rollers should be of mohair short pile and nothing else!! Just before launch the hull needs to be sanded lightly with 240 grit to activate the CopperCoat. This needs to be a minimum of 1 to 2 weeks after application but can be longer.

What happens if you don’t follow the instructions?

We look forward to seeing the result of this product on Destiny. We can only judge so far on the results in the Mediterranean on the sailyacht. After the first year when she was lifted, the entire keel was peeling and covered in bubbles – as were parts of the hull. She was sandblasted back to bare GRP and the product was applied again – properly this time. Now, 5 years later, it’s a different story. All we have to do is give her a clean while we’re swimming with a sponge cloth and jet-wash when she is lifted.

The factory has been read the riot act about the application process as above! We’re confident they will do the job properly and we’ll report back the results when we see them.

Ultrasonic Anti-Fouling

This is a new one on us! Ed spent a long time with the suppliers of this product at the METZ trade show in Amsterdam and also at the Dusseldorf Boat Show. We decided to try it out and see if the claims of the manufacturer were indeed true. We can’t comment yet … but watch this space.

This product is not a paint at all – it is an electronic anti-fouling device which emits ultrasonic signals into the water. The idea is that the marine life is repelled by the sounds – which of course can’t be heard by humans. They will hopefully go away and pick another boat to stick to!

The manufacturers say that it doesn’t replace anti-fouling paint but it does prolong the life of the paint and improve the performance. Combined with our CopperCoat, we are hoping for an exceptionally clean hull! However, we are starting our cruise in the tropics which has the worst conditions for hull fouling. We are therefore testing the combination in the harshest way.

What is this product?

The Ultrasonic product consists of a small control box which operates on 12 or 24 V DC. There are also AC versions available. We have gone for the more powerful model – the UltraSystem Power Plus. The product emits a range of frequencies and comes with a 5 year warranty.

The box can be installed in any convenient location. It connects to sets of transducers which emit the ultrasonic signals through the hull into the water. The supplier provided us with an installation plan based on our boat and we have four transducers in total. These are not through-hull transducers – so are easier to install.

The current draw of the DC system is a maximum of 6.8A @ 12v or 3.4A @ 24v. The average draw much lower than this.

Amorsil Anti-Fouling Paint

The last part of our armour in the war against marine growth on our underwater gear is Amorsil paint. CopperCoat cannot be applied to any of the underwater mechanical parts (except for the rudder) and neither can most other anti-fouling paints. For this reason, the prop and other moving parts underneath are often still fouled. They will need regular cleaning in order to maintain the performance of the boat.

Prop Paint

We are applying a product called Armor-Sil® R/G to the moving parts. This means the main prop, the bow and stern thruster props. This paint is especially designed for mechanical parts and is a silicon based, non-ablative paint.

Apex Marine Solutions, who supply the product, inform us we can expect 10 years of good performance. If it lasts for that long we’ll be delighted!

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