Friday, 6 September 2013

Keel hardwood and stern tube fitting

First thing to organise was the keel wood.  11 pieces of 150mm x 75mm kwila that were 3600 long.  These things were VERY heavy, craned off the truck but then carried in one at a time by me.  Hope the strong back lives up to its name!

I mentioned in the last post the stern tube I am fitting through the keel.  First step was to mark on the hull where the shaft line hit the hull using the drawings.  Then I started dry fitting pieces until the tube was supported from the hull to where the propeller will be.  From the inside I drilled up for the temporary threaded rod.

I used a piece of PVC pipe the same diameter as a guide as I carefully chiseled out a sloped hole through the glass/ply hull.  Once through and widened until the pipe fit (required inside and outside work so I didn't destroy the inside ply face)  I found it was going to pass through the hardwood cross piece on the bottom of frame 8.  Once I had made a start I drilled a 10mm hole through the hardwood using the sloped cut as a guide so I could work from both sides of the hardwood.  After much time and repeated climbing from inside to out and back again I could slide the 2000mm pipe up from the inside.

Below is a shot showing the slot in the hull as I pushed the tube out from the inside:

And an overhead shot showing the pipe lying (hopefully) on the centre line of the keel and into the hull:

A side shot of the same, my drilling of the holes was a bit angled and cramped inside of the frames.  If necessary I will cut off the rod as the keel gets higher and drive some drifts (I think they are called) from the top down as these rods will be permanently epoxied into the keel:

An inside shot from the side showing the path of the tube through the hardwood on frame 8.  It is probably not needed but because I have cut some of the cross piece out I am going to put an extra piece of hardwood across the centre line 300mm each side to spread the load from the bolts.  Basically epoxy/coach bolt a doubler of hardwood over the top:

And a slightly out of focus shot showing the engine end of the stern tube sitting over the top of frame 7:

Next is to build wooden supports on the inside of the hull where the pipe is located so when the whole thing is epoxy/glued in you can fill the whole lot up.  That will be in the next post along with epoxy/gluing the first bit of the keel in place first.


  1. Nice and professional pipe fitting method.
    I really got something good about pipe fitting.
    Gekko Inc. has smart solution of it by offering swagelok fittings.

  2. Glad you enjoyed it, John Welsford used two pieces of wood with a notch in each lengthwise which you then clamped around the tube. Just another option.

  3. I like this fitting techniques.
    Woodward 8250-565 is a good choice for your unit.
    It is a high efficiency tool.