Its a question that people seem to like asking. "where do you start".
In my case the beginning of the restoration started with what I considered then to be the most important safety feature, after hull integrity that is, namely to check the condition of the infamous 7 keel bolts.
Having spent most of my adolescent and adult life messing with mechanics in one form or another , mainly cars. I did not foresee any real problem with removing the bolts. After all they were a good inch thick , so I assumed that they would relinquish there hold onto the keel after some judicious use of a large lump hammer.
My original plan was to remove one bolt and to inspect it for corrosion. Popular opinion seems to be that an 1/8 inch wastage is acceptable as the number of bolts holding the keel on is reassuringly excessive.
Armed with the appropriate ¾ inch drive socket and not insubstantial "T" bar , a can of penetrating oil , my vernier callipers and the all important lump hammer , I felt cautiously optimistic that by the end of the day I would have the offending bolt removed and inspected
Initially all went well, within 20 minutes of so the nut had been removed and I was ready to persuade the bolt that it was time to leave the snug home it had lived in for the past 40 years. I replaced the nut so that I would not damage the thread ( in my naivety I thought that I may be refitting it later that day!).I gave the nut a good firm blow ,and inspected it for any sign of movement .Many a bolt has given me some resistance over the years, so I was not overly concerned that this bolt showed no obvious signs of movement.
Over the next two hours the severity of the blows and the size of the hammer progressively increased until it became obvious that the head of the bolt ,complete with nut had ostensibly been cold forged together to form what I can best describe as a steel mushroom!
Trying to think laterally I decided that most of any potential corrosion would be in the area that the bolt passed through the wooden floors. The obvious answer was to remove the old timber floor so I could make my all important measurement .
The wood literally fell apart when I started to chisel it out. This was quite alarming , yet I consoled myself that it was much better to find this out mow rather than whilst I was healing at 45 degrees in a stiff breeze. The bolt had wasted by ¼ of an inch just above the keel plank. I now had a bent 1 bolt with a nut which was never going to come off again , showing no sign of wanting to be removed. Not the result I had been hoping for by the end of the first day!
The options were very simple . I could keep on trying to remove the remains of the old bolt, and all the others. I could leave the old bolts where they were and hope the keel would not drop off! Not a real option , but I thought about it non the less. Or I could re drill the keel for new bolts.
The latter seamed the most plausible option until I worked out just how thick the cast iron keel was! It was then that I came up with the final option, which was the one I would end up implementing. My plan was to drill the keel in between the existing bolts, and then tap the hole with an M 20 tap to a depth of 4" ( 10cm) .
I cut a 2" core out of the keel plank to expose the top of the cast iron keel. This went well. I hired a large drill from HSS and bought a large quantity of drill bits of ascending sizes up to 17mm which was the final drill size to suit the M20 tap.
The drilling started well with the hole drilled up to 12mm. The 17mm drill bit was very slow to cut , but after an hour or so the first hole was drilled to the correct depth. The tapping went like a dream I used the correct set of three taps, the final one being a plug top which cuts the thread all the way down to the very bottom of the hole,( I wasnt prepared to loose even the smallest amount of strength from my hard fought hole Id drilled .).
The second hole seamed to start as the first had until I was 2" in with the first drill bit which was a 6mm. It just would not drill. I replaced the bit with a new one, applied more cutting compound, but it still wouldnt drill. It was then I was beginning to realise that the keel was not made from 1st class cast iron. Rather it had been made of second hand recycled metal of dubious quality, all melted down with cast iron. I spoke to an engineering friend who said it may be that I had hit a piece if scrap that had not melted before the keel was cast. The chances were that it was either hardened steel, or chromium, both of which had a high melting point. The suggestion was a bit mad, but it was to sharpen a tungsten tipped masonry bit and give the drill some grief!! I was very surprised and relieved when I broke through the mystery metal and resumed drilling in the comparatively soft cast iron.
By the end of two long days all the new holes had been drilled and tapped . I encountered several other hard spots during the drilling , but they all eventually gave in to the relentless assault from my array of modified drill bits
The hard work was finally behind me. The new studs were made for me by a local engineering company from half hard steel alloy . they had threads cut on both ends before being sent to a local galvanisers to be galvanised. Once returned , the threads wee cleaned out using caustic soda, so that they would fit the tapped holes properly.
All the new studs were greased prior to being threaded into the keel for the final time.
The new floors were made from 2" seasoned oak. They were cut using a band saw to match templates that had been previously taken from the bilges The final challenge was to drill a 1" hole through these new floors .The further aft I went the deeper the floors became. The final floor required a 1" hole to be drilled through 18" of hard oak , making sure it was kept in alignment! But the wood working problems are another story altogether!