Wednesday, April 19, 2017
Rudder Centreboard and Keel fitting
It's been a while since I last posted and really that's because I procrastinated too much about what steps to take next - paint inside the hull or turn it over. Once I got my plan straight, we made decent progress:
The bronze hardware had arrived, thanks to Ballentines Boat Shop who were extremely helpful and knowledgeable and Brian who collected the parts for me while visiting relatives nearby, so I made some progress towards completing the rudder.
Here you can see the gudgeons being fitted to the leading edge of the rudder. Once I had these installed, I removed then and sheathed the rudder with fiberglass woven cloth. This resulted in a reasonable finish but I reckon I will need to finish with fairing fillers to get a smooth finish. I decided to sand off the glass where it curved around the trailing edge as it seems to stand somewhat proud from the boards edge, so I will also finish this with fillers.
Next I made some further refinements to the centreboard. I followed a useful instructions sheet
published by the Gougeon Brothers which recommended drilling out the hole oversize , with wide chamfers at both sides of the board, for the bushing and remaking with glass cloth soaked in resin and finally assembled with a large bolt and two washers to squeeze the resin impregnated cloth into a smooth bushing.
The result was quite encouraging and I hope will last well. Here's the finished result shown here with the bronze rod inserted.
So bolstered on with this progress, I assessed that the next thing I needed to do was turn the hull.
I wanted to drill the hull for the lead keel bolts, but the floors beams would have been in the way, so I concluded turning the hull was the only way forward. Also I needed to seal the edge of the ply planks with epoxy resin and do some final fairing of the hull - best accomplished with the hull upside down.
Before I could turn the hull, I needed to the chain plates to the hull, as this process requires drilling holes in the hull. Making the blocking board to fit between the hulls strakes and the bronze chain plates was quite slow and tedious, necessitating several attempts before I got clean fits. I wanted a tight fit rather than relying on epoxy to fill the gaps, so that I could varnish them to show off the bronze chainplates. My friend Brian came along to help, which was just as well as it was quite a brain teaser trying to figure out how much and which way to tilt the band saw.
Here on the right, you can see the chain plate installed where it protrudes through the side deck beams. Although it looks a little long here, there is an other Sapele deck to go on top. I didn't cut the hole for the shroud as I have not taken supply of the rigging fittings and not yet sure what size to drill the holes.
Inside the hull, you can see where the chain plate is fitted to the backing plates.
Once the chain plates were installed, it was time to turn the hull. Last time I did this with my friend Brendan and we managed quite well (at least Brendan didn't complain too much when I had him holding most of the weight and being squashed against the wall to protect the hull...thanks Bren!), but since then quite a bit more has been attached to the hull. We set up two slings out of the ceiling, plus this time we had the benefit of the steel RSJ which we had fitted along with a sliding carrier for a block and tackle, not to mention two extra pairs of hands, thanks to Brian and Bren's son Scott.
However we slung the hull too high, so when it came to turning it over we couldn't get it to clear the ceiling (only 8ft - compared to beam of 6ft) so we had to reset it into lower slings and with much huffing and grunting we got her turned! It's really a challenge working in such confined spaces - we had to practically rearrange the workshop to perform this simple task.
Once we had the hull turned over, we set to dry fitting the lead keel. This is where the block and tackle running along the RSJ made for a smooth process.
The keel sat very well onto the hull with only very small gaps - so the time and effort I put several months ago into fine tuning the keel's shape by using copious templates really has paid off.
I was quite looking forward to the challenge of drilling for the keel bolts - yet everywhere I read, the perceived wisdom seems to be to drill from inside the hull into the lead - which makes a lot of sense, because if the holes come out of the lead a little off line, it would never be seen. However since this wasn't an option for us, we make a drilling template block taking the drilling angle off the plans and converting this on the pillar drill into the drilling guide.
This was simple a length of 4x4 stock equal to the width of the base of the lead keel, into which we drilled to holes at 4 deg angle off vertical to allow for the bolts to exit inside the hull at the preordained positions. We checked our template block first by inserting 10" long 1/2" dowels into the drilled alignment holes and measuring the distance from each end to see that it corresponding gap on the plans.
Next to the actual drilling process. I had read so much about how drills break in lead and go off line, so I decided to use a simple brace and wood auger bit, which was quite hard work but very effective and we ended up with very satisfactory holes exiting either side of the centre board trunk inside the hull. Here you can see Brian hard at work. I read that acetone makes for a good lubricant for drilling lead, but I compared this to cutting fluid and found the latter to be much more effective. Once we made through the lead, I switched to a hand held electric drill to go through the wood, which speeded up the process. Since by 3/8" auger bit wasn't long enough to go through both the lead and deadwood at the same time, I finished off the deadwood when we removed the keel, having made a deep guide hole to ensure we were perfectly aligned.
Once these holes were completed we fitted the bronze threaded bar, which was predominately 1/2". We had used 12mm auger drills , but the 1/2" bar was quite easy to thread into the slightly smaller 12mm holes which will hopefully make for good water tight seals.
Since we had such a hard time turning the hull, I didn't even contemplate leaving the lead on before turning the hull right side up again, even though I saw how Dave Johnson in his blog did so quite successfully. So I faired in the forward part of the keelson into the lead and also the deadwood at the transom. I will leave the final finishing when the keel is bolted on permanently and the hull is right side up.
Lead keel safely back on the trolley |
Labels:
And,
Centreboard,
fitting,
keel,
rudder
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