It's been a few years since I buiilt mine but I don't remember any major problem with the planking around the prop - mostly it was a faff drilling the hole for the shaft. I didn't worry too much about it because I was going to cover the hull with body filler.
Thanks, Sulaire, greatly appreciated. I have to confess to procrastinating on this and have skipped a few stages to work on the superstructure! When courage returns, I will get back to planking the hull.