Windows & Entrance

Here are the side windows for the boat.

I had these CNC cut which did not cost much more than the cost of the Acrylic. I simply emailed the DXF files and picked them up. The edges are polished and look great. I didn't trust myself to do a good job cutting them, so it is nice to know they are exactly the shape designed for the boat.

I then used the actual windows to mark out the hole.

Next job was cutting out the area which will become the hatch and entrance for the cabin.

Obviously, lots of care needed here, so I took my time using the multitool to get a nice clean and straight cut.

The pieces I cut out will be used to help form the sliding hatch and entrance panels.

Cabin continues

The outside of the cabin is now really taking shape. I used the laser level to get both sides of the cabin to match, and added an extra layer of ply on the inside to strengthen the chain plate area. Then the roof is placed on as two layers of 4mm ply to get the curve.

I thought I would add this photo after speculating in the previous post comments about how it will sail. The hulls are fairly slim with a 16:1 l/b ratio.

Starting the cabin

Time now to build the cabin. The process of getting the roof profile is tricky especially as I have to repeat it exactly for the next hull.

Going off the plans, I drew a grid and copied the intersecting locations on the grid to get the roof profile and then screwed two pieces of ply together to cut out a matching piece for the starboard hull at the same time.

I now have a lot of pieces ready to go for hull number 2. It will be interesting to see how much less time it takes.

With the cabin starting to take shape I can get a feel for how much room will be in there. There should be plenty of room for overnighting and more. It is probably the most space you could reasonably expect to have in an open deck cat this size.

The back

The aft deck has is now almost finished.

The Rudder gudgeons are fixed in place and the deck is reinforced for the beam loads. The beam mounts are not on yet. Because the hulls are not being built at the same time I might wait until both hulls are finished before adding the beam mounts so I can get the alignment exact. I will likely add an outboard mount to the inboard side here also, but it might wait also until the other hull is finished as it's location is partly dictated by the beam location.

Front deck

After at least a month of not being able to do any work, I have resumed the fun.

From this angle you could almost be fooled into thinking the first hull is complete. The truth is far from this.

I have mostly completed the decking of the bow area including the main beam area. The decking under the main beam mounts took quite a lot of time for not a lot of visible progress, compared to plain single sheet planking which is actually very fast. There is significant reinforcing to take the loads from the main beam here. I still need to take to the hard edges with the router but I'll wait for the rest of the decking and cabin before doing that.
I have left the hatch sitting in it's cut out mostly just to stop dust, screws and whatever else might be around from falling in there.

Hatch

I have prepared the port bow hatch.

I did some research on hatch types and sizes and thought about what kind of stuff I will be putting in here. This hatch is big enough for the anchor I have in mind and a bucket for chain etc. The locker will easily fit fenders and extra stuff also. I also put another small inspection port in the bulkhead aft of the locker to allow ventilation because there will be wet things in here. The starboard hatch will be identical.

The hatch is not actually mounted yet. This will happen once the deck is glassed and painted.

This photo shows the deck with measurements, ready to cut.

More Wood

I had a drive across town to get some more supplies.
What you see here is a few sheets of ply and some nice Mahogany which will be used for beam mounts and hatch trim.

This should be the last wood I need to buy for the boat!
I bought 3 more sheets of 4mm ply and 1 more sheet of 6mm. I have bought 1 more sheet of 6mm than stated in the plans and 4 more sheets of 4mm. I probably could have used 1 less sheet of 4mm if had been more efficient cutting for the rudders.

Also I have machined some more wood for framing for the Cabin and Deck.

Starting to deck

The bunks are all done so next on the list is the deck. I am starting with the easiest part of the deck, being the forward area. This will be good practise before getting stuck into the tricky parts of the deck where the beam mounts are.

This is basically the same process as hull planking, but with a few extra things to do, such as plan for hatch and cleat placement. Also time to add extra epoxy to any wood which will become hard to access once decking is on.

Here you can see the process for marking out where the forward hatch will go. First use the laser level to line up the forward bulkhead.

Then put the deck panel in position.

Then measure off the laser line and mark out where the aft edge of the hatch will be.

Easy as.

Bunks

With all the focus on getting the hull finished and upright. It took me a while to think about what to do next.
Here you can see the first of the bunk panels being made. The 9mm ply here seems strong enough without any bracing needed.

I have been using an electric planer and the power file again proving very useful here to shape the panels. At about 900mm wide and 2 metres long this aft bunk should be a nice place to get some rest or sleep.

Right way up

A major milestone here as the first hull is turned over. It turned out to be easier than I thought after a test lift showed it wasn't too heavy. 4 people kindly gave me a hand to do the job. The boat was basically turned by one person lifting the bow and another lifting the stern while the rest of us guiding it and putting supports in place.

I took the opportunity to weigh it at this stage and it is currently 87Kg's. I hope I'm on target for the designed weight. It looks a lot smaller now but is much more interesting.

Paint

Got some paint on the boat now. I have used 2 part primer and a 2 part top coat below the water line using small rollers and a brush.

I have still not decided on a colour scheme for the top sides but have primed anyway.

Also, the rudders have had the same treatment and are pretty much finished!

Fittings

Now is a good time to put in the bolt for the fore stay.
I have used thickened epoxy in an oversize hole and backed with a washer. Then filled with epoxy filler and faired. The plastic you can see in the photo is just food wrapping plastic, which I use for most jobs like this where you want to be sure you get enough filler and reduce sanding.

Also I have drilled the holes for the rudder gudgeon's. I had these gudgeon's made up by a local workshop in 316 stainless to the designers specifications.

Painting Prep

With the cloth on, the bottom of the boat now just needs to be painted. Sounds easy but lots of prep to do. Not only to the boat, but also the rudders which are now at the same stage so might as well do them at the same time.

Here you can see I have added some west 407 filler to the boat and rudders. Then sanded smooth.

Lots of sanding here. I hope the neighbours forgive me. The boat acts like a speaker box when machine sanding, it was loud.

Boat cloth

I have covered the bottom of the hull with 200gsm fibreglass cloth. With two layers on the keel for extra protection as I plan to beach the boat a lot.
I started by applying the first layer on the keel only and cut it along the chine with a blade while the epoxy was still at the gel stage. Then applied a second layer over the whole hull.

 I was reminded of why I don't much enjoy doing fibreglass work during this session. The second layer took 5 hours non stop.

It has been very cold in Auckland lately but fortunately my garage is a fairly controlled enviroment and with a heater and dehumidifier I am able to do this kind of work.

I am mostly happy with the result. A few runs here and there and a couple of air bubles to sort out. It seems a shame to add all this weight of cloth and resin to the boat, but it should make it last a long time with less maintenance.

Filling and Filleting

Time for all those holes to be filled, sharp edges and corners to be smoothed and shaped in preparation for fibreglassing. Also the decision on weather to flip it over now or mostly finish the bottom first needs to be made. Flipping it over will be no easy task, also with the height limited in my garage once the cabin is on means I will be at least painting below waterline before flipping it over.

I have run a router down the keel chines with a 38mm bit giving a 19mm radius. There is a trade off with the chine radius. On one hand a large radius will be less prone to damage and easier to fibreglass and perhaps help the boat tack, but on the other hand a smaller radius will give the hull better 'bite' in the water when going up wind.

At the Bow I have used a 50mm router bit which has resulted in a near perfect radius at the bottom where the bow is about 50mm across. Again there are trade offs with bow radius. My preference is for a more blunt bow shape. In this case where the hull is very narrow, it is actually quite hard to get a sharp bow, as the sides of the hull converge at a very small angle.

This fillet for the inner wing is huge. Here I am part way through making it, I used about 3 litres of west filleting blend filler and used a compact disc for the radius. I have often thought about how strong this part needs to be so I haven't skimped in this area.

Bottom Covered

The bottom of the first hull is now covered with ply. It has for the most part been quite easy, I got into a bit of a rhythm with the process of marking the wood, mixing epoxy, coating, gluing/screwing. The hardest part was the sheet at the bow on the inner side where there is the most shape.

Another tricky job was making this curved plank. I had to scarf the lengths allowing for the curve by marking the scarf lines with the lengths placed at the desired angle then sanding to the marks which resulted in the angle of scarf changing across the joint. It worked well.

One milestone was the removal of the holder for the bow bulkhead which up until now had been doing a very important job. But has to go to allow for trimming and shaping. You can see it is missing in the top photo.

Another handy tool

Here is some more pics of the planking.

Here I'm using the scissor jack again to line up a sheet.

All of this work needs a lot of screws to hold the sheets on while the glue sets and would be much harder without the use of this handy tool.

This is just like a cordless drill but without the troublesome battery, lower RPM and more torque than a standard power drill. 12V? 18V? try 230V, works way better and never goes flat :) The torque settings are great for putting the screws in fast.

Getting my plank on

Finally I get to start closing in the hull. One last look before it gets covered. This pic really shows the shape of the boat very well. I have found two new things that are taking up more building time, staring and daydreaming :)

I have prepared one side of the plywood sheets by coating with epoxy, sanding and coating them again. This gives a very nice smooth clear finish to what will be the interior of the boat.

You can see in this picture I am lining up the second sheet on the outside of the port hull. I am using a car scissor jack to have good control over the location of the sheet to butt it against the first sheet. Once in place, I put a few screws in and then use a pencil to mark the location of stringers and framing on the interior side of the sheet. Then I remove the sheet to prepare it for mounting.

Using the pencil lines as a guide, I cut out the shape (slightly oversize to allow for trimming), drill the holes for the screws and sand where the stringers and framing will be.
Then I apply epoxy to the sanded areas and to the framing/stringers then thickened epoxy glue over the top, then screw in place with a lot of screws and tidy up the squeezed out glue. Then the next day I remove the screws and get ready for the next sheet.

Inspection ports

I decided to put these in while access is easy.

I used this hole cutter which attaches to a drill. Then sanded the edge and applied epoxy. Once cured, I used marine sealant and screwed into place with stainless screws..
One port is in the forward bulkhead below the storage area and one is in the stern. Both areas serve as watertight bouyancy. With this boat, I want to be able to regularly inspect all areas.

Planking Prep

With most of the stringer fairing done, a few more jobs need to be done before planking begins. One of them is butt blocks for joining the panels. I will scarf the keel and inner wing but I have decided against scarfing the large side panels due to the size as I am building this all by myself so full length side panels would be too hard to manage. The butt blocks are made from the same 6mm Okume as the panels which I cut on the table saw which allowed me to quickly make a lot of them straight and identical in width.
I used a router to take the majority of wood out and also use a power file to tidy it up.

Then simply glue them in place. I will sand them as I go around the hull double checking everything is fair.

Fairing Stringers

Now that the stringers are all on, they need to be faired so that the outer surfaces will line up with the planking, and give a good surface for glue adhesion. For this I am using a combination of electric planer and belt sander. Checking as I go with a steel rule.

Making a Plank

To make the bottom of the boat appear as one continuous piece of wood, scarf joints are needed. With the fairly narrow width of the bottom of the hull it makes it an easier job for my first attempt at scarfing plywood.

So here I have some 9mm Okume and I have marked out from the end of the plywood lines to indicate where to sand to to give a 12:1 ratio angle. On the bottom is some 12mm ply to stop the lower piece from bending at the edge. This stack is all sitting on a large wooden beam to raise it off the ground making it easier to work. Then using a belt sander I sand to give the two pieces a matching angle, this is basically the same method I used for the stringers.

Then I lined up the lengths of ply with the laser level, glued and clamped. The result was a perfectly straight plywood plank about 7 metres long.

Stringers all on

Now that the stringers are all on, the shape of the boat is clear. Before putting the stringers on I found it hard to visualise the inner wing toward the bow as it is fairly complex how the angles converge, but it ended up being quite straight forward in practise.

Other potential KD650 builders will find this photo interesting. Locating stringer X at the stern. Using the laser level and a steel rule, x marks the spot.

Update

Stringers Part 2

I have been adding more stringers to the hull. Time has come to do the keel stringers, as mentioned by Bernd, cross cuts need to be made on one side of the stringers to assist the extra bend toward the stern.

Here you can see the cross cuts made in the keel stringers. I used a skill saw and adjusted the depth of cut on the saw, then clamped the stringers together, marked equal spacing then it was a fairly quick job to do identical cuts to both of them.

Here you can see the resulting mounted stringers. Glued in place with a little help from gravity.

I am starting to get used to having this big thing in my garage. Looking even more like a boat now.