Thursday 31 July 2014

Forward cabin still - lead keel?

I have continued slowly with the forward cabin.  Next on the agenda was to sand down a few ply joins that were not quite smooth and then epoxy the underside of the front deck (the roof of the forward cabin).

Below shows the view looking forward on the starboard side above the overhead storage.



A shot showing the forward laminated beam on frame 2 and the forward king plank (in place for a powered chain winch down the track):




And a slightly wider/lower shot showing both king planks, laminated beams and between them the forward hatch coming down through the deck:



The main thing occupying my mind at the moment is the ballast keel.  I was going to cast one from lead, then I decided to get a steel keel box and put the lead in it with some epoxy to hold it in place.  Suggestions were made on the wooden boat forum that this was not really necessary, and casting a keel wasn't that hard. After changing my mind several times I have decided to have a crack at casting it (that will be news to my father who will get roped in again, last I told him I had gone back to a steel keel box).

So I bought some ply 15mm thick, cleaned up all the wood I had from the strong back and frame supports and started to make up a mould.  

The finished keel will need to be 3370mm long 150mm wide with a height of 180mm at the rear sloping up towards the front.  

Below is the end piece (left) followed by the double layer which is a slope to match the existing deadwood at the front of the keel, and then the single layer that goes to the right of the picture is the first layer of the base of the keel.  It slopes back to the end where it will be 180mm high.



A wider shot as I mark out the position of the base on the side of the mould. 


This is the first layer, with the end pieces in place.  Front with the slope is at the bottom of the picture.  The ends and bottom are glued and screwed with 25mm chipboard screws (bottom on 150mm centres).  There were 500 in the box I bought, and I used plenty.  No point saving them!


Back outside for the second layer all round, again screwed and glued top and bottom of the ply faces and a few in between as well.



Once I got two layers on all round I flipped it over and screwed wood supports underneath the bottom two layers.  These were glued and screwed in from the sides with 75mm hex screws.  I put a couple of supports below out of picture under the front of the keel as well, the space above was too small and I have another plan for those.



I had the ply left over, so screwed a third layer on the front, and a fourth on the outside which was also screwed into each of the side layers.  This is the front slope from underneath, note the Australian safety boot in the bottom of the picture.



This is the front from above looking into the mould.



Lastly I cut some 140mm x 40mm from the disassembled strong back into shorter pieces.  These were glued and screwed (four each side of 75mm hex screws) and will be drilled for 5/8" threaded rod which will have nuts and washers on the outside.  This is to hopefully stop the mould from sagging outwards under the weight of the lead.



A bit blurry, but across the bottom of each of the uprights is another piece with two hex screws each side up into it to hold it all together.  You can also make out just on the bottom left between the two double ply sides the two other underneath supports.  On the top double side you can see the hex screw that goes through the two layers of the side and into the support to hold it in place.  Hope it is strong enough.


One of the cross pieces also holds the end of the supports in place, where there is not enough room underneath it for a full piece of wood I am going to use hardwood wedges left over from the kwila keel to prevent any sagging downwards.

Still to do is drilling the holes, fitting the threaded rod, possibly some 6mm ply inside each side, putty the inside joins and paint it with silica.

Oh, and get more lead and talk my father into making up something to melt the lead in.

2 comments:

  1. Wish I could help Mal, with that pour. Huge! I am sure you will make out fine, just keep the sweat drops out of the hot lead...

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  2. I'm sweating already, worry though not effort!

    ReplyDelete