Advice repair to sheerstrake

[GeoffNZ]

Hi, Need to repair sheerstrake on my folkboat

Any suggestions what to do with copper nails where rove is inaccessible on the inside of the boat behind the clamp - half of securing nails cant be punched out.. Makes springing the plank to scarf it difficult. I assume scarfing is way to go but seen mention butt blocks but how to secure these at the top. Try to scarf in situ?
Position under chain plates. the soft area., a short scarfed in repair of pine (removed) and need to space plank joins means a 2.5 m plank is needed. Plus need to replace a short section of plank below it.
Planking is mahogany, frames oak. I've removed teak gunwhale.
Have a plank of sapele mahogony 100 mm x 18mm is this likely to bend for sheerstrake about midship on 26 folkboat without steaming. Sapele OK for planking? Original sheerstrake made of two narrow pieces edge bonded.

 

[Hacker]

With regards to the nails. You could drill out the head and then spring the plank off and cut the remaining nail flush. However, you then need to think how you are going to fasten the new sheer if you can trove a nail. Scarfing iOS always neater but you could use butt blocks if you have the space for them. You would fit with bronze screws through the plank and into the block. Not sure if the sapele will bend, suspect you will have to try it