Friday, 23 August 2013

Stem cap and keel holes

After plenty of looking at the inside, measuring, checking with a plumb bob and marking it was time to drill holes up through the frame hardwood cross pieces and through the bottom of the hull.  I also ran a string down the centreline on the outside and marked it with permanent marker.

The keel will be 150mm wide hardwood, the most important holes are the ones in frame nine and ten which will pass each side of the fibreglass tube the propeller shaft will run through.

Below is a picture of the fibreglass tube, 50mm external circumference:

Also made up a template of the keel, I am thinking steel keel box filled with lead ingots at this stage:

Took some deep breaths, used a square and the frames to try and get the holes as vertical as possible and drilled them.  Ones at the front and where the keel will go are 10mm, down the aft 8mm.

Frame 2 10mm hole:

The stem was laminated at the start of the build and incorporated into the hull with stringers and finally planking.  Now that the sides are done it was time to cover it with hardwood and continue it up over the bottom where it will meet the keel.  I got 90mm wide strips delivered, plan called for 5 x 5mm but my supplier could only do 8mm.  Final result is still 24mm or just short of an inch thick so I think it will be okay.

A piece of hardwood was needed to fill in a space where the ply bottom finished (had to meet a hardwood cross piece at the other end of it).

Nails were removed once dry, the front (left as you look) planed down to an angle.  Managed to plane a bit off the end of my finger but only minor.  Made me pay attention though, it has been a while since I used the electric plane.  Then the first layer went on.  Started to pull down the high end to the right angle, snapped it in half at the bend.  After a panic attack I realised I would have to use the snapped piece in the middle of the three.  I had previously seen on the woodenboat forum (where I get all my boat building advice from!) about bending wood.  Marked each end of the curved area, wrapped it in a hand towel and poured boiling water over each side and let it sit.  After a few minutes while still hot bent it around the curve, screwed in place and left it for the epoxy/glue powder to set.  Worked a treat.

Cut a fill in piece of hardwood to fit on top of the first to support the cap, pulled it down with a strap and the second layer went on in two bits, join is about half way so that the curve and top is one piece.  Wrapped some cling wrap over where it will be layered into the keel, you will understand later.

Then the final piece:

And in close up, note the extra hardwood packing piece:

Filled the screw holes (screws were removed once each layer had set and re used so there are no screws in the cap anywhere) and blended the hull join with filler powder.  Checked my drawings and plans, and cut off the cap.  After a bit of sanding and clean up this is the result:

Close up, the cut out bit is where I had the cling wrap so the first and second layer would not stick together:

Cap to hull filled and sanded:

And looking back along the hull.  Don't worry about the lean on the back threaded rods, it is 8mm rod in 10mm holes so there is a lot of movement.  The first one is 10mm rod in 10mm hole and is standing nearly perfectly.  I am sure they are not perfectly level each direction though I must admit.

Fairing part two

Once I was sick of the first side I started on the second.  It didn't seem as bad and I think some of my early coats on the first side were too thick and ran so much that I was just wasting epoxy/filler, time, energy and sanding paper.

The second side seemed to benefit from the early mistakes.  If you remember on the bow I tried to use a notched spreader to make grooves with only partial success.  After sanding and filling I stuck with the thin coat, sand, recoat process which seemed to work okay.  Maybe I was just over it and decided it was good enough.  I have moved on to the keel prep and start (next post shortly) and haven't taken any shots of the second side.  It looks like the first, see below for the final outcome.  I may go back as I work on the keel and do small spots if they bug me, but we will see.

Looking down the first side after final sanding:

Looking from the side at the transom towards:

Looking aft at the top curve:

Lastly looking aft bottom curve:

Next post will be prep for the keel with holes drilled through the bottom and building the hardwood stem cap.

Thursday, 1 August 2013

Fairing part one

Had a few computer problems so have not updated for a while.  The fairing of the hull continues, this would have to be the worst part so far but I am getting there.

After the first layer of epoxy/filler powder was dry I started.  First I made a sanding board so I could sand the curves.  These are also known as torture boards, and with good reason.  The ply is 6mm so I can bend it around the curve, I cut slots near each end to feed in sandpaper from a roll and screwed extra ply on top to hold it in place.  Couple of handles screwed on and away I went.  The idea is you sand in different directions/angles and the bend in the ply stops you sanding flat spots because it will take the curve of the hull as you press in on the handles.

I also have another sanding block similar to a bricklayers trowel with a handle, very useful as well.

Although I thought the hull was quiet smooth I soon discovered all the little dimples in the hull.  The pattern of the fibreglass mat, even though I coated it a number of times, was still there.  I tried using a notched spreader with the epoxy, the idea being you sand it hitting the high points and then fill in the hollows.  I didn't mix the epoxy thick enough and it ran together instead of leaving peaks.  Luckily I only did the front on one side as an experiment.  I'll let you know because it is on the second side I've just started. 

After starting sanding the entire hull and putting on a second coat I decided to work on a single side at a time for my mental health.  That way I could see progress as I did each coat.  I have left the bottom until after I have made the keel.

This the side I did first after sanding:

The other side:

The next coat going on:

Sanding and re-coating a couple of times I found a thin layer scraped with a wide plastic spatula was better than doing thick coats which ran and needed lots of sanding.  This is the front:

And looking towards the transom:

I still have a few spots to sand after today, I had a bit of mixture left over so went back to a couple of small hollows.  The above photo was when it was still wet, the shine goes with the final fine sand.

The other side which I am now working on, this is early sanding:

 And the most recent layer today:

And looking towards the transom:

I will continue on sanding and layering, and will continue with the next post including final shots.  But this takes a while!