The Hull is underway!

Got my 9mm ply delivered, mainly cut into 200mm wide planks with two sheets cut into 100mm wide for the bow where there is a sharp curve into the stem.  Also got a supply of Phillips head stainless steel countersunk self tapping screws, 8 gauge x 5/8" to attach the planks.

Then there was no more procrastination, it was time to start.  I had planed and sanded the frames stingers so was hoping the shape was not too bad.  Time will tell.

Plank One.  Each plank has three screws (countersunk) at each stringer position, the plank itself is on about a 20 degree angle.  The planks are epoxy glued to the stringers only and not to each other.  When you screw the second layer on at about 90 degrees to the first it forces glue into the joins between the planks.

I got two planks out of each 2400mm x 200mm piece of ply with a little bit left over.  As you can see below I didn't bother cutting off the bottom, the building guild recommends at least 50mm past which I assume is to ensure full epoxy all the way past the stringer.  After the two layers are on and the boat rolled over you trim it  to the stringer.  This is frame 8 to the transom which was a days activity.

The shot below is looking along the hull, and you can just see the shape/curve starting to show itself.  Maybe you cant, but I got a bit excited anyway!

As you can see there is quite a way to got, don't expect the two layers to be done quickly.

Bottom layer done

I have been fairing the stringers in preparation for planking the hull.  To get the top right you need to put the first layer of 9mm ply on the bottom as the sides overlap it.

Instead of cutting a scarf along the face of each sheet and overlapping them, making a very long sheet that would be near impossible for me to position, the designer John Welsford uses a different type of join.  The first step is to cut a zig zag pattern onto a template, each tooth 30mm wide and 50mm high.

Then you transfer this onto the ply. making sure that you offset the template on the second piece so they fit together.  I did one end of each of the four pieces, and marked the others to suit when assembling.

Once I had cut the zigzag, I positioned the piece and marked the edges and holes for countersunk stainless steel screws then took it off and cut/drilled.  Make sure you leave space on the centreline as there will be keel bolts coming through.  Each piece is screwed on about 200mm spacing along the bottom stringer as well as across way into the hardwood cross pieces of each frame.

I started with a small section between frames 3 and 5 which was necessary to ensure I could use a full sheet across the floor of the 'cabin' without a visible join.  Then I marked the front one out, sides and end and cut.

Then the main full length one followed by the one that meets the transom last.

 
A couple of inside shots which start to show how the hull is closing in:

Inside looking forward galley (fr 5 to fr 1)

The main cabin looking toward the cockpit.  The middle bits of wood are a temporary support for frames 6 as there is no hardwood cross piece in the main cabin.  The two small pieces parallel to the centreline are to support the sides and form the engine box.

And finally the cockpit to transom:

More fairing required and then order some ply for the hull.

Stringers done - Happy New Year!

With much patience from family (and doing a little bit at a time then waiting for epoxy to set overnight) I have finished all the stringers.  Spent a bit of extra time hanging around and cleaning up each of the stringer/frames joints as much as I could removing excess epoxy.

On to photos, enough chat:

First three stringers done looking forward:

Looking overhead from the bow, three done on one side:

Looking overhead from transom forward (removed temporary wood between each frame):

Completed from the front:

From the side at the bow:

From the side looking back:

From the side at the transom:

Inside looking towards transom:

Inside looking forward, galley on left and over supports for berth to frame 1:

Started some clean up of the stringers and sanding the sharp edges off on the inside edge, leaving it square where it will meet the hull.  Happy day.

Stringers III - the inbetweeners

For those that came in late, each of the main stringers (I'll call them how I see them now on the building jig, top, middle and bottom) are made from three pieces of 20 mm x 25 mm clear hoop pine laminated together.  This gives a final piece 60mm wide let into the frames a minimum of 25mm.

In between each of those goes two evenly spaced smaller stingers, two 20mm x 25mm so only 40mm wide. I scarf cut and joined wood to make the first four pieces that are full length.  Then I had to mark out and cut the notches in each frame for them.

To do this I measured the distance between each of the main stringers and marked the frames.  Then I got the straightest of the four and lay it along the frames so that it sat on each of the marks.  A few minor adjustments and I could mark out the bottom of the notches.  I used a metal rule to take the angle of the stringer looking from the side and marked a line on each frame, and carried it around onto the the fore and aft face of each frame.  Then using the stringer as a guide measure the distance you need to let the stringer into the frame to maintain the curve and mark it.  One side will be 25mm where the edge of the frame touches the stringer, the other will be more to allow the stringer to curve in.

Remove the stringer and use two pieces of the wood to mark the top lines, carry the lines around the side and mark the 'let in' measurement up and you have your notch marked.  I used a hand saw cutting from the outside towards the centreline and followed the lines.  It seemed to work okay, make sure you are checking each side of the frame as you cut as they are not the same depth front and back.

Now do this so you end up with 78 notches marked (don't count them until you have finished) all hand sawn to the correct depth and angle.  I decided to mark and cut them all first before fitting any stringers, it just felt more efficient as I was into the swing of marking out.

Feel free to curse, particularly when you lean in to check a measurement and bang your head on the middle main stringer or crack your shins on the bottom one.

Using a chisel carefully take out the waste material working from each side.  The cuts will prevent the frame wood splitting, and some will almost come out with a few hits from each side.  You will be surprised how angled rear to front the final result is towards frames 1, 2 and 3.

Below is part way done, note the extra depth to be taken out on the forward side of the frames (up to 30-35mm in on the very front ones to allow the curve.  If you look closely on frame two, three and four right hand side you will see that the notches are waiting for cutting, chisel work and finishing.

The below shot is a close up of the side to show hopefully the different depths:

And a final shot from the front:

Next update should show the inbetween stringers in place, things should move along a bit quicker but after the Christmas break.

Stringers continue

Slowly but surely moving along.  I am only scarfing together long bits six at a time (three each side) as I move up and adjusting the notches takes a bit of time.

Finished the lowest ones (while upside down), someone pointed out it is the most important one as it defines the visible line of the edge of the deck.  I should have started at the top (under water) then the middle and the most important one last as I got into it.  I still have four each side between the main ones so too late now.

First one finished:

Middle one first piece:

Middle one side done, first on the other:

Below is the middle one finished, on the top left hand side the first one on the chine to bottom stringer is done.

Gunwale stringers 1

Started on the gunwale (I think that's what they are called) stringers.

First thing to do was join my wood to make it long enough.  For that I made up a saw jig which fits the wood inside tightly, with an 1:8 angle across cut to fit the saw.  Pictures will explain it:

Below is the jig from scrap looking from above

This is cutting the scarf to make the join:

And below is a close up of the end result:

Once I had six long bits, adjusted the cut outs on the frame and epoxied three on one side all in together at once.  What a nightmare trying to force three pieces together, bend them and clamp them by myself while the epoxy in the pot goes off.  I ended up chucking most of the first lot of epoxy and having to make up a second lot.

This is the final result of the first one:

For the second side I have decided to change tactics.  Seemed much quicker adjusting the cut outs in the frames, but I have the first ones to measure off to see how much to take off.  Decided to epoxy the lowest one on alone first, making sure it follows the marks on the frame.  The other two will then be dropped in together on top over the day or two when I get the chance.

From the front with the second side epoxied and clamped in place:

Started on the chines - method

Each of the main stringers, the front to back bits that fit in the frames and give the hull support and shape until finished, is made up of three pieces of 20mm x 25mm Clear Hoop Pine.  The designer said it was easier to laminate them in place from three pieces rather than try and bend a 60mm x 25mm piece of wood around the curves.  Having started on the first one, I believe him.

There are three main ones each side.  The top and bottom, and a middle one which is located where the two curved sections meet.  It will become clear hopefully as the photos and chines go on.

There are also two small ones which run from the back of the cabin to the transom, and change the top (when right way up) curve into a straight side.  Basically the hull section has no curve above this little "tumblehome" (I think) stringer to the top of the hull, it is a straight line and actually ends inboard of the curved hull below it.  On the below photo, from the centre stringer piece to the bottom is straight (boat upside down still), above that is curve up to the middle full length stringer.

It also had the advantages of being short, and wouldn't be seen by anyone as it will be inside and underneath the cockpit when finished.  A perfect one to learn on!

I will explain the process, then as subsequent stringers go on I will stick to photos and brief descriptions.  To fit the stringer it is necessary to:
1.  Using a single piece of wood first, adjust the cut outs on each frame so that the stringer forms an even curve.  I initially was using a chisel, but got a rough wood file which seems to work much better.  You really only need to take extra wood off the frame edge on one side where the stringer touches it.  Trust me this involves putting the wood on and off a hundred times until you think it is right.

Below you can see how the right hand part of the frame was adjusted as the wood curves in on that side.

2.  Once you have the first one on, I put the second and third on together and got them to line up with the first which was clamped in place separately as a guide.
3.  Once all three are on, pull them all off and epoxy glue them on.  I glued the first (bottom one) on by itself and then the top two together.  Final adjustments with the use of many clamps, including making sure that all three lined up vertically and horizontally.

Below you can see the clamps holding the pieces together in each direction.

Once all the stringers are on it will still be necessary to taper part of it to match the change in hull curve.  It is a bit hard to see, but the very top of the three stringers is a couple of mm outside the curve and will be sanded to match the curve above it shown by the frame.  From the middle stringer piece to the bottom of the photo should be a straight line with no curve.

Some wider shots.  All clamped on and glued:

From the side:

From above:

Finished with the ends trimmed: