Monday, 28 October 2013

Keel complete (some tidy up to go)

Once the last layer epoxy/glue had set the final steps could get underway.  First off was to fit a capping piece on the end of the keel where the rudder will attach.  A piece of hardwood 60mm wide was clamped and glued into place with the join well covered:

Once that was in place I sourced some hardwood tongue and groove floorboards 20mm thick which when each side was planed to square were exactly the right width.  After a bit of a plane of the keel I trimmed them to the shape:

And stuck them on top with a thick layer of epoxy/glue:

Then it was time to cap the front slope of the keel.  First step was to mark 50mm each side of the centre on the existing wood and plane each side of the keel so it sloped from 150mm wide to 100mm   This left me with a top surface which I put a cut down piece of keel wood (75mm high) onto.

The aft end of this piece meets an end cap on the remainder of the keel which also widens it back out to 150mm.  At the same time I got two pieces of wood and angled them up so they finished where the lead keel will start.

Below shows the cap piece being glued in place, the rear most lead ingot shows the slope up and just to the right of it you can make out the angle to meet the other 150mm wide wood.

Once dry I marked an angle from the stem cap back 600mm to the top surface and planed the front cap piece down.  The final step was to fill some holes between the keel and hull where I didn't quite get the curve right.

After jamming in as much epoxy/glue powder as I could I lay a thick fillet along the join and used a 90mm diameter PVC pipe wrapped in cling wrap as a tool to pull along the fillet to get a nice curve.  Quickly lay on a 100mm wide fibreglass strip and wet it out.  Below shows the result:

As you can see from above and below I then rolled on three coats of epoxy wet on wet over the entire keel including the top.  Below is looking down the keel, you can now see the planed down front cap and the ski jumps which will hopefully help the keel ride up over whatever I hit!

Final shot below shows the worm shoe in place and everything epoxied.  I planed some of the wood off the end of the keel in front of where the propeller goes above and below the shaft line to help improve water flow:

Final steps for the keel are to fillet the remainder of the keel/hull joins with sanding/filler powder and then fair the bottom surface out to the hull curves.  I probably will not have an entry just for that but will include them in the next one which I am excited about - the roller over and support cradle to stand this thing right way up.

Monday, 14 October 2013

Keel stack finished

The stacking of keel timbers continued and they are now all in place waiting for the epoxy/glue to set on the final layer.

First off was to drill and position the galvanized threaded rod through the hardwood cross piece in frame two and up through the keel.  After drilling up from inside each end was countersunk using a 22mm spade bit.

I measured the length using a piece of small rod and cut it:

Then tightened it in place.  This one is permanently epoxied into the keel and will have a cover piece above it on the keel.

Below is layer four of the level pieces, this one extends toward the keel.

The last 320mm is tapered from 150mm wide to 70mm to assist with water flow onto the rudder.  Below shot is looking from underneath, 150mm wide just below the lower clamp:

Layer four aft piece in place, looking along towards the transom:

And from the transom looking forward:

The final layers in place, 5 in total at the front.  Note the lead ingots (25kg each) helping to hold the wood down:

Seven layers at the back.  The top two at the transom only go forward 1540mm to allow for the end cap which will be positioned to line up with the transom (18mm thick).  In front of that will be a lead keel:

Looking forward:

Next steps will be:

  • tidy up the keel using an electric plane to get rid of the excess glue, 
  • fill gaps and fibreglass tape the hull/keel join,
  • fit the caps on the front(which will also require a taper) and rear, and
  • fit a worm shoe on the top of the last rear layer.

Tuesday, 8 October 2013

Keel continued

Last post I had just attached the wood each side of the stern tube and filled the hull join with epoxy.  Next step was to build up the rear and front until the keel was level along it's full length for using the long kwila planks.

Below is building up the front, note the string level.  This continued on the front but I didn't get photos because of a mad rush to glue it all down, more on that later.

Down the aft I managed to glue the threaded rod in early you will remember.  To overcome this I came up with a cunning plan. First I drilled some 10mm holes in four bits of wood.  Each was placed over one of the rods, and then cross pieces screwed between them, with the edges of the cross pieces lined up with the edge of the keel wood underneath.  Finally long pieces were screwed between them all to lock it all together.

I used 10mm holes for 8mm rod so I had a margin of error when I drilled the future keel wood.  Below are some photos showing firstly the drilling jig sitting in place but not positioned or clamped to drill.  MARK fwd and carefully align with the edge of the keel wood and the direction and top face, the holes will be in the wrong place if you don't place it correctly before drilling!

Close up showing how it is all secured together for accuracy:

And an after shot showing the third layer aft piece:

Now some shots of where I am up to, covering the tube and level to the hull (dry fit):

Same but closer and from aft:

Second of the level layers glued in place, note the forward packing pieces to make it level and angle cut for capping piece:

Still second layer but looking aft:

Level layer 3 aft glued from a distance, the next layer will go right back to the transom as the space for the propeller has been left.

Same but close up:

I have decided to glue up each layer as I go instead of making the whole keel dry and doing a final single glue up session.  However when I placed the first full length piece I have managed to leave some gaps between the keel and the hull due to curve in the piece and not enough weight to bend it down.   After much consideration I have decided I will glue up the remainder of the keel and after final shaping (the front and rear have to be planed down to make them thinner) I will fill the gaps with thickened epoxy glue and fillet/fibreglass tape the hull/keel join.  It may not be necessary, but I will feel better knowing there is a layer of 200mm wide tape holding it in place.  The finished keel will also be given a few layers of straight epoxy.

Onwards to more layers, final stack will be seven layers high, with the top two having a large space at the front for the lead keel.