Saturday 28 August 2010

Fitting the Keel Box

Friday evening was spent re-levelling the boat (pre-going to the pub!) just to make sure that the boat hadn't strayed off the perpendicular and horizontal. Sure enough, what wih the workshop being a shared space and all our leaping in and out of the boat she had moved a little. We checked the waterlines marked on the bulkheads using as our level a clear plastic tube filled with water. The height the water is at one end is always the same height at the other and with two of you it is very easy to check all round the boat, not to mention cheaper that a laser level. Before long we were happy that the boat was level and we could head to the pub knowing that the keel could be fitted quickly in the morning.

The keel box went in a just a little more than a push fit so we had some wiggle freedom required to align the keel. You can probably also see the small bit of sail batten sticking up on the leading edge, this was to replace the material we took away when cutting the keelbox from the keel.


With the boat nice and level we then put in the keel and made sure that she was vertical and with no twist. We effectively ignored the keel box.


Once the keel was properly aligned we u-pol'ed the keel to the floor of the workshop! Not going anywhere now! I am sure there are better ways to to this, but we do love U-Pol!

The other thing we did before glassing in with our usual fillets and 100mm 450 +-90 was to add a little more support whilst we worked within the boat, especially now we had a hole in the bottom and the keel was perfectly aligned. Nothing complicated, just a few planks to support the bottom of the hull.

And then we glassed her in. Note that after we had filleted the keel box with a micro-fibre resin mix, but before doing the taping we added some overlapping patches of some more 450 +-90 on the hull at both the leading and trailing edges of the keel box to take the load of the keel into the hull in case of grounding etc. You can see the extent of the patching by looking at the peel-ply on the hull in the picture below. We have 3-layers; 100x100mm, 250x250mm and finally the last layer of 400x 400mm.

Next we will add the logitudinal on top of the patching, extending from the keel box to the bulkheads just fwd and aft.
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3 comments:

  1. Unknown28 August 2010 at 22:31

    Hello,

    On the first picture you can se something black on the back of the kkeel box.

    What is this and what is it used for?

    /Perry

    ReplyDelete
  2. Guy29 August 2010 at 07:19

    Hi there. This is some acetal. I tend to use DELRIN, a crystalline plastic which offers an excellent balance of properties and has no/low water absorbtion. I have specified a basic extrusion (1"x1") which we have sent through the router to cut out a section to take the keel trailing edge. It does a couple of things:
    The first is to give at least one point of contact on a low friction bearing surface when we are lifting and dropping the keel.
    The second and primary reason is to make sure that we spread, i.e. do not point load the back of the keel box where there is a danger of splitting the glass and/hull under loading. It's something that we use on the newer laser dinghies to protect the roto-molding as well as canards on larger sports boats and cats.

    ReplyDelete
  3. twill2 September 2010 at 09:00

    looks good!

    ReplyDelete

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