Re-clenshing

[joeirish]

I'm thinking of purchasing a clinker dinghy but it looks like it might need re-clenshing because it doesn't take up fully. How easy (or difficult) would this be? The dinghy is 12 foot and has about 10 planks either side.

Would there be likely to be problems with rot in the frames which has caused the nails to pull out?

Thanks

Joe

<hr width=100% size=1>Joe Griffin

 

[tillergirl]

I wouldn't think that rot will have caused nails to put 'out' but I'm not sure what you mean by pull out?

If she is copper roved (ie round roves over the end of copper nails), removing the roves and releasing the nails is relatively easy if a bit repetitive - grind off the burred over end of the copper nail and the rove will either fall off or be easy to lever off, punch out the nail and there you are. If you don't have roves ie the nails are clenched over at 90 degrees, removing will be a little harder. If there if a lot of room between the planks you can cut the nail in half and remove each half with a little bit of levering or just try and lever the end straight and punch out.

Refastening, you need the mating faces to be as clean as possible and bring them up tight before the rove goes on. In my experience the rove has too little grip on the nail to withstand a lot of pressure to pull apart until the end of the nail is riveted over. That means working out how much of the existing nails to remove at a time so that you can get the mating surfaces together and held together while you rivet up - but I have to say this is probably harder to read about than do. You will be best served with the right tools - a punch with centre recess to drive on the roves, snippers to cut off the surplus on the copper nails, a pointed dolly for someone to hold on the head of the nail while the inside with riveted up and the Yorkshire Ripper's favorite - a ball pein hammer (is that how you spell it) to rivet or burr over the end of the nails.

A facinating and satisfying task if you get it right. Crucial question for me would be the condition of the planks. If there are signs of spliting along the nails, then reclenching is going to be problematical. The odd cracked frame is not a problem to replace.

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[joeirish]

Thanks for the very informative reply. Vey useful.

I'm not sure why the seller of the dinghy thinks it needs re-clenshing but I have read that the reasons the roved nails no longer hold the planks together could be because of rot in the frames. That was what I meant by 'pull out'. Is there another reason why she no longer fully takes up and is there another solution to this type of problem other than re-clenshing?

Joe


<hr width=100% size=1>Joe Griffin

 

[tillergirl]

The trouble can arise from poor maintenance or just the repeated strain of drying out during winter and then swelling on launch. The extent of drying over a winter period can vary considerably depending on the storage conditions and how long she stays out. I was late relaunching my 25' bermudan sloop one year which happened also to be a dry warm spring. Where she was in the yard meant that the sun beat down on the starboard quarter that was exposed belwo the bottom edge of the cover. The stern also was exposed to any easterly winds of which there was a lot that year. Result when I launched that part really took a while to take up. Take up it did but I see now some 15 years later that the current owner is looking at replacing a couple of planks because of a linear crack running in line with the fasternings.

Essentially what is going on is the plank and frame contracting and expanding - probably at different rates - the frame is more protected from the elements - and the fasterning remains as is. Result, the fasterning loosens up. If there has been poor maintenance or poor quality materials the postion is made worse.

I refastened a section and was really glad I bothered. Crucial to get the mating faces clean and enough released so that the mating faces will pull together and not put an unexpected strain on the adjacent unreleased sections. Once done keeping up the maintainance and avoiding excessive drying will help enormously.

As to rot in the frames - yes well if they are rotten or indeed if the plank is rotten the fasterning will be loose. A rotten plank will not take up and refastening with existing frames that are soft or cracked is pointless. But a clinker boat is a kit. Provided the majority of the timber is sound and the price of the package is right, and, you don't mind a bit of work, you can't really go wrong.

Bad frames need to be replaced and require steaming. Again not the most difficult thing in the world but just needs some planning, preparation and a willingness to give it a go. Replaced a couple on my current 32' carvel built boat a couple of years back and it was quite an enjoyable and satisfying process.

Other solutions - well someone might say stick some suitable mastic into the gaps between the planks or even caulking it. Not me though. Clinker was not designed to be watertight that way and even if you get a temporary fix, you will be straining those parts that currently don't leak and starting a new round of problems. Someone will probably now post saying they did it and had no problems!

Good luck

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[joeirish]

Thanks again for the really helpful advice. I now hae plenty of information to help me decide when I view the dinghy.

Joe


<hr width=100% size=1>Joe Griffin