Sunday, 27 May 2012

How to make frames, and frame two

I now needed the space to draw the frames full sized, so set up a lofting floor from 3 sheets of MDF giving me an area 2400high and 3600mm wide.  Below is looking across the area, note ply screwed to hold it in place.

To make a frame first it is necessary to cut the solid wood for the sides to scarf it together.  To do this I drew out the shape on cardboard using a 100mm grid and measurements from the plan, then cut out the curve.  This was then used to draw the shape on the solid wood which was cut out.  You end up with a top and bottom piece both oversize for each side.

On the floor you mark the centreline and the waterline across.  From the plans you measure three points, outside top, outside chine and outside bottom  (up/down from waterline and out from centreline).  The template you cut from cardboard and marked on the solid wood shows you these three points as well, check the plan to make sure, then lay the two cut pieces of solid wood on the floor so they are touching the points (one will overlap the other).  Mark the scarf on one (I used the bottom one, it was shorter), cut then lay back down and mark the scarf on the other piece.  

Cut and epoxy together and there you have your side piece.  Mark the cut outs for the chine.

The bit at the bottom of the photo is laminating solid wood on the rear of a 9mm ply partial bulkhead and 20mm x 20mm solid pieces which will have plywood to make storage areas.

Check it all on the floor, cut out the solid wood for the keel bolts and stick it together

First photo is the rear face, 20mm x 20mm pieces are for a later fit out of plywood to divide storage spaces.  Note the 9mm doublers over the scarf in the solid wood each side.

Below is the forward face.

Thursday, 24 May 2012

Frame 1

The first frame has a full sized 9mm ply bulkhead that will be filleted to the hull making a watertight space between the bow and the inside of the cabin.  This is in case you hit something, not a thought I want to consider.

Because it was full sized, I drew (lofted) the frame directly onto the ply I was going to use instead of onto the lofting floor which was much easier.  I had previously cut a hole for a waterproof hatch and epoxied a doubler on the other side to help support it.

I didn't take many photos because I was too busy getting it finished so I could feel like I was under way.  Below is a shot looking at the at the rear face of the bulkhead.  Visible at the very bottom is the hardwood on the front face that will be cut to fit the stem and keel bolt.

Below is an overhead shot to give you an idea of the curve in the solid wood frame.  The line of horizontal dots above the hatch are countersunk screws into a solid piece of hoop pine on the forward side with a hardwood doubler.  At the top you can see the first laminated beam attached, this will form the forward edge of the deck.

The horizontal wood on the forward side has a notch cut for a hardwood plank running along the centreline to the stem.  It will have a small lower deck/step down area to stand in when up the bow or attending to the anchor.  It will also be a good spot to put your feet and sit on the higher deck where the beam is.

Looking from the beam down the centreline.

This is now up to date to where I am at as of about the middle of May 2012.  I have started frame two but will not post an update until it is finished.

Stem and Laminating Beams

The stem and beams for the boat are all laminated rather than cut from solid wood.  Happily I found this to be nowhere near as hard as it looked on the internet or sounded in the building guide.

First step was to purchase all the wood.  Again I got it from Lazarides Timbers in Brisbane and went with clear Hoop Pine.  I ended up getting with the computer age and made up an excel spreadsheet (after making an early mistake and ordering lengths too short, another lesson) to cover all the combinations.  Each beam had a thickness of wood lamination (6mm or 8mm), a width of each lamination (20mm, 30mm or 45mm) and a number of laminations in the beam.

Take your time, fill in the spreadsheet and DOUBLE CHECK each beam on the plans and document BEFORE ordering the wood.  Trust me, I now have a number of Hoop Pine 6mm and 8mm pieces in various lengths that I will recycle somewhere in the future.  The left over 40mm x 40mm off cuts from the rudder were perfect for the corners of the hatch (last post) and I'm sure I will find a home for them.

Next step was to layout the jig.  John Welsford recommends making up a lofting table from 3 2400 x 1200 pieces of plywood or MDF (making a total area 3600mm wide and 2400mm high) to make the frames up on.  This is a very wide boat and the frames require a lot of space to make up.  Once the frames are done you then use the large flat area to make the jig to laminate the beams and stem on.

This involves screwing hardwood brackets to the surface to clamp the wood onto to form the curves.  A horizontal line is drawn, 200mm spaces are marked long its length and the brackets are moved vertically up various distances according to the plan for the beam.  When you clamp the epoxied laminations to the brackets, a curve results.  Bigger curves result from the end brackets being closer to the horizontal line and the middle being higher.  The hardwood brackets keep the laminations up off the surface so you don't stick it all together and are covered with glad wrap (cling wrap) to stop the beam sticking to the bracket.

I was still building the tender and didn't have the room to make up and leave a full size lofting table in place, so I came up with my own solution.  I got several thick pieces of straight treated pine and lay them on the concrete floor which I had checked and I knew was level.  I put enough pieces down that I could cover the highest position in the centre (some of the longer ones are quite a large curve) and long enough to cover the lengths (the longest was over 3000mm).  

I forced them flat and screwed ply braces across all along to ensure they stayed flat, flipped it all over and marked out my 200mm base line.  Instead of making up hardwood brackets I went to Bunnings (hardware chain store in Australia) and purchased steel brackets just long enough to cover the width of the widest beam.  I went a bit thicker with the steel to get it higher off the wood and also for added strength when clamping.

The picture below shows how it works, I stopped taking pictures after the second beam because they all looked the same.  Thankfully of the eleven beams I made there are some with the same curve and just different lengths (four of one curve, two of another). This sped the process up a lot, because I didn't have to remove and reposition all the brackets for the next beam.

The stem was a similar process, although the grid was in two directions and I had to make a base running horizontally and vertically.  The stem is also 15 laminations of 45mm x 6mm that are 2600mm long.  You can  scarf (fancy word for join with an angled cut) some of the internal laminations but as I was ordering the wood I went all full length.

The plans recommend doing the lamination in three sets of five, FOLLOW THIS RECOMMENDATION!  I was surprised just how much epoxy and time it took to cover five laminations on each inside surface, position and clamp them.

You will need to beg/borrow/buy/steal a lot of clamps.  I cleaned out my father, father in law and brother in law and also bought some for down the track.  There are 21 proper clamps on the stem below, plus a few more spring loaded ones I put in spaces after I ran out.  Not sure if the spring ones held anything but the looked the part.

Below are the first five clamped up.

 Then the next 5 for a total of 10.  

Then the final five.  This created the next complication, because the final stem thickness is 90mm and my brackets were only 75mm long, however with the thickness already in place to clamp to it was not an issue. 

Came straight off the brackets with a light tap of the hammer and was cut to length (with a bit extra).

Forward Hatch

By far the biggest challenge so far was the forward hatch.  The designer John Welsford had designed a hatch that was traditional in design from what I have seen on the internet.  It had a hinged joint on the forward end (ie couldn't be forced open by waves from the front) with the interior higher than the join between the outside surfaces.  This meant that any water getting through the from the outside would hit the inside layer, which was higher, run down into the void and then back outside through drain holes.

The interior I decided to make from clear Hoop Pine, with the outside from a medium weight Australian hardwood.  The space between the interior and exterior was 15mm, created by spacers of 20mm x 15mm clear hoop pine.  The curved top of the hatch was three layers of 3mm ply bent to shape.

Below is the dry fit of the interior which I started with.  Interior dimensions of the hatch are 600mm x 600mm.  You can see the hoop pine spacer will be secured with stainless steel screws and epoxy.

Below the spacers will have the deck come through right up against the inside surface.  This will require a little bit of cutting as I cheated.  The designer's plan called for some very nice hardwood corner pieces cut to fit on an angle with the inside and outside surfaces coming in to meet them.

I looked at it an could only see me stuffing them up, so I decided that I would simply make two of the inside pieces butt up against the outside at ninety degrees and I would screw through to hold it together until the epoxy set.  I had to put a bit of thought into it and it will become apparent later how it goes together.

Below you can see the spacers epoxied (with glue powder) and screwed to the outside of the inner layer, along with the exterior epoxy coated.  These surfaces will come in contact with any water that makes it through the join between the top and bottom halves.  Epoxy should protect them hopefully.  

The two rectangular ones in the middle are the ends with the small one being forward, the sides show the slope which matches the deck camber.

Below is a close up showing the counter sunk drill holes for joining (top left and bottom right partly obscured) along with the join.  You will note a large gap that indicates my measuring mistake.  I later filled it with more thickened epoxy.

Once dry I epoxied, screwed and clamped the inside together.  Later the next day I came out to admire my work and found that I had stuck on one of the end pieces upside down.  Do NOT panic and rush thinking the epoxy will instantly set.  I had a problem with one part and in the rush stuck one of the four pieces on the wrong way up.

When you find a mistake, don't rush into trying to fix it either.  I almost lost it and tossed the whole thing onto the concrete but a few deep breaths, a hacksaw blade along the joint and through the screw holding it and I got the offending end off.  Put it right way up, drill a new hole as the old one still had the bottom half of a screw in it and all was well.

I then measured up the hardwood for the bottom of the outside and epoxied the inside surfaces which would complete the drainage void.  See below:

These were then screwed and epoxied onto the spacers and the screw holds filled with thickened epoxy.

Below is a view from above looking down into the drainage void.  Note the gaps at the corners, which I had made to fit some left over 40mm x 40mm hardwood which were off cuts from the first few layers of the tiller (see earlier post).  You can see two of them in the bottom right of the picture near my right foot.

Before I fitted the corner blocks I wanted to make the top half so that I could "adjust" the corners to cover up my poor woodworking skills if necessary.

Below you can see the hardwood cut and sitting for epoxy glueing and screwing.  You will see that the curve cut in the front and rear ends is the same, but the height is different.  Welsford's design called for a building jig to be made and the ply moulded prior to fitting.  I was too lazy so decided to try to use the hardwood itself to provide the shape.

My biggest concern was that the base would be out of square too much for the top to fit.

Unlike the bottom half, the top could not be screwed together and support itself due to the modifications I had made to the design.  There was nothing for it but to epoxy and fillet it together and see how it went.

Thankfully it worked and through careful checking of diagonals and adjustment after clamping it was fine.  I then shaped the top of the wooden corners on the lid and stuck the bottom hardwood corners on.  They were a few mm off but some sanding of sharp edges and they looked good.

Then it was time to fit the curved top of the lid.  Firstly three layers of 3mm ply were cut to size and holes drilled for the curve.

 It was then epoxied between the layers and screwed onto the hardwood with the screws on about 50mm centres.

The top was then covered in two layers of epoxy after sanding.

I gave it a flip and put more epoxy on the inside including fillets along the edges and joins for strength.  I decided not to glass the top, time will tell if I should have or not but it seems to be very strong.

Then the standard two coats of oil based undercoat/sealer and two coats of exterior grade house paint.  The inside was not epoxied, nor was the exterior hardwood.  Only the joints along with the top curve inside and out and the void.  In addition the top was painted the same blue as the tender.

In the photo below if you look closely at the outside bottom you will see two dark dots.  These are the 10mm drilled drain holes which go on a downward angle from the inside void to the outside.  Each had epoxy on a cotton bud rubbed along the inside surface, but it is hardwood and that may have been more for my sense of mind than any protection of the wood. 

Below shows the removable hinges from Whitworths Brisbane.

Below: Inside are adjustable stainless steel latches.

Below if you look along the bottom edge of the top half you will see rubber sealing strip which provides the seal between the top and bottom when compressed by the latches.  It will be a while until I can find out if it is waterproof!!

Lastly put in an adjustable hatch support that holds it open.


Another side project was the bowsprit.  First off was to laminate three 80mm x 40mm pieces of Oregon pine to give me a single piece 120mm wide and 80mm high that was 2050mm long.

Remember I mentioned in an earlier post about learning not to leave until the epoxy had set tacky and excess was cleaned off?  Look at the tender in the background and you will see what I mean.  If you look at the bowsprit you will see the extra squeeze out that I should have cleaned off BEFORE if set.  Do not repeat this mistake!  You will rue the rush to get to the beer inside the house, trust me.

This was then shaped according to the plan.  The photo below probably shows the final shape the best.  The bottom face (resting on the saw horses) is flat with the top surface sloping up to a centre section that is the full size of 120mm x 80mm.  It then slopes down the the right hand end which is where the fitting goes which is not yet cut pending fabrication and galvanising.

The picture below is looking from the fitting end and shows how the bowsprit tapers from the middle toward where it will meet the boat (the far end).

Below is the final result with two coats of oil based undercoat/sealer and two coats of exterior grade house paint.  Once I finish the final shaping for the fitting I will have to drill holes etc and complete the paint.  Note at the top of the photo all the thin pieces of wood to be laminated into beams, see later post.

Wednesday, 23 May 2012

Rudder and tiller

Whilst waiting for epoxy to set on the tender at times I started on parts for the Sundowner.  I had ordered the plans from John Welsford after exchanging emails and discussing stretching it a little from 21 feet 4 inches to 23 feet 8 inches (12%).

Once the plans arrived and wood obtained (Lazarides timber in Brisbane) I firstly started on the rudder and tiller which looked like something I could handle.

First off was sixteen lengths of 40mm x 40mm timber with a maximum length of 1880mm.  As you can see below the first four were hardwood for strength followed by 12 of medium weight softwood of decreasing length.  Just up from the base, and at 400mm/800mm above is a horizontal 6mm 316 stainless threaded rod with nuts and washers on each end.  The initial locations were drilled with a drill press to ensure they were horizontal, then I carried the holes through with a cordless drill.  As I drilled each one, I used it as a template for the next.  While I was concerned about the final hole being off centre it worked fine.

The picture below shows the rudder epoxied and bolted up.

Once the epoxy was dry I took the rudder and shaped the profile using the scale drawing supplied with the plans by JW.  If you look carefully on the rudder, in particular the right because of the colour of the wood, you can see the spaces where the nuts are located on the threaded rod.  Once shaped thickened epoxy was used to fill the holes to match the surrounding shaped rudder.  I started gently cutting pieces of waste off after marking the profile on the bottom of the rudder, but was making more of a mess than anything.  Out came the electric plane and shaping went well after that.  Very small amounts off at a time, then final sand.  There was one area where I cut too much off prior to getting the plane out, which was filled with epoxy by levelling the surface on saw horses and pouring it into the hollow.

To reinforce the rudder, each side of the top is also covered in a 20mm thick support from Australian hardwood with epoxy and screws.  Prior to fitting I cut the hole for the removable tiller to fit in, lesson learnt from the tender build where I forgot to cut the recess prior to putting on the outside supports (realised on my way to work when congratulating myself on how well the tender rudder epoxy went).  On the right you can see the tiller made from two pieces of shaped hardwood lap joined with stainless screws and epoxy.  I used joined pieces to reduce the waste due to the curve, and there was no noticeable decrease in strength.

Close up of hardwood supports and tiller recess

Below you can see the 9mm plywood baseplate and the 50mm centre holes for attachment to the bottom with 14 guage (I think) 316 stainless countersunk self tapping screws.

This is the final result with the screw holes filled with epoxy.  If you look you can see the baseplate has a fillet of epoxy between the ply and the vertical wood.  Another benefit of making the tender, my fillets are getting better with practice.  Bottom right is a claw hammer which gives you an idea of the size of the rudder.  It is taller than me, and runs full length of the transom from the base of the keel to the top of the cockpit cover.  (Please excuse the boating terms, still learning them and I think I have that right)

Another angle closer to the bottom, note the shape at the top of the softer wood to allow attachment of a rope in case of rudder issues.

Side on view of the tiller showing the curve, and right hand end which fits into the rudder.

Final result below waiting for down the track.  Entire rudder has been coated in two coats of epoxy, then I got carried away and put two coats of epoxy two-pack undercoat and sealer on.  I need to do a bit of sanding on the tiller hardwood to get it to fit into the recess.  I epoxied the recess figuring it would be easier to repair/replace the tiller (maybe a nice laminated one with different layers of dark hardwood and pale softwood like Charlie Wipple's on the JW website) than to repair the rudder from water damage.