Planks are bevelled so that they contact their respective planks on each side tightly. If you put a plank onto a hull just get a square edged plank and butt it up against the one that is fitted. You will see that due to the curvature of the frames they will not meet tightly there will be a gap as they do not meet at 90 degrees. So bevelling is the art of making them meet correctly and the bevel does change as the strake goes from stem to stern. In practice though you will only need to be roughly right.
I only bevel one edge but I may be the odd one out here. So working from the garboard plank upwards I would bevel the plank that meets it and leave the other edge square. I would then bevel the edge on the next plank that meets that one and so on. The very last strake of planks will have bevels on both sides.
Also I always make the last strake of planks somewhere near the middle of the ship. So I start planks from the garboard upwards and also from the whale downwards and then meet in the middle. I hope this helps - Mark
I've also had this issue and changing the belt made no difference either. I contacted Jim who advised me to place a couple of washers behind the tensioning spring. It's a little fiddly to do but it works great and is a permanent repair. It just pushes the motor back that little further which is what is required.
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