Week 20 - Ballastkeel / Slidinghatch

In my post of week 7/8 I allready described how we prepared the ballastkeel-plug for Irons Brothers to cast the leadkeel. And here you can see how both the leadkeel and the plug got delivered.
We were very happy with the result and they have drilled the holes for the bolts as shown on our drawing... excellent.

The first time since many weeks we lifted the boat out of it's exact level position in the cradle, placed her on 4 trolleys and moved it under the crane.
The leadkeel has a weigth of 498 kg and therefore health and savety played a big role when handling it.
For that reason we decided to build a drilljig for drilling the boltholes instead of dryfitting the real keel and drill through those holes.

That drilljig consisted of a sandwich of 3 sheets of plywood as visible on the photo to the right. And it both allowed to place the drill at the right position as well as in the right angle (6 of 9 bolts are in an angle!).
The drilljob with this jig let us achieve a very accurate result... all 9 holes came out at the planed position on the topside :-)

Now the next thrilling moment... will it fitt or not?
Yes it fitted excellently!
What a good feeling,... this was a bit of an unsure thing because of the fact that the plug had to be fashioned oversized to respect the shrinkage of about 0.5% when casting lead. With other words... we never had the chance to check the fitt of the plug before!

A cleansweep over the contactsurface and ready for the final fitt. I should mention that we've sealed all drilled holes with epoxy overnight!
We used 3M's Marine Adhesive Sealant 5200, a very sticky white material which we spread over the whole topside of the ballastkeel.
All 9 bolts are 3/8" in diameter and made from siliconbronze rod.
When tightening the nuts we had to work in intervalls with breaks of some hours inbetween to give the sealant time to spread and get the most of the airvoids out.

The photo to the left shows the dryfitt which made us really happy :-)

Some of the very last elements was the sliding-hatch on the coachtop. This was not the easiest part of the boat to be honest ...but i wanted to get it very well working as well as aestethicly nice too.

To reach that goal one of the most important things was that both rails on the coachroof got positioned very very accurate.
They both have a routed 4mm wide slot (see photo) in which the brassplatefitting will slide in the future.
When glueing the rails i aligned the slots to the exakt heigths at each end with the help of a selflevelling laser.
What a fantastic tool... it made accurate work so much easier!

The mentioned slidingslot was prepared with very fine sandpaper and masked when varnishing. The idea was to get the slot oiled and waxed in a second step... the oil as a lubricant and the wax to avoid drying out of the timber. And this way the slidingslot can easily be maintained later.

The hatchshell itself was made out of 2 sheets of marine plywood, cold molded over a former in the shape of the coachtop below.
An inner frame and an outher frame all in sapele mahogani made the whole slidinghatch very rigid and formstable. Thinking about the fact that the boom can touch the aft end of the hatch when lowering I made this part extrastrong and it also is a nice way to get a good grip with your hands when moving it.

I'm sorry for having no better photos of the finished hatch below.... they are a quite unsharp, but the boat is now covered until spring :-)
However, they give an idea of how the slidinghatch looks finished...