..the port side cabin forward corner post. I also had trouble keeping up with the mahogany corners on Passage. One treatment that worked for me was when the August sun beat down upon..oh wait, that's a song..uh, when it got hot and the H. Mahogany cabin sides shrank back a taste, I cut straws in half lengthwise, taped the halves over the cabin side cracks and poured in liquid Polyseamseal, a water based product. It's a white milky look going on that cures clear. It is thin and penetrated well into the slight gaps. After curing I cleaned off the surface and did my usual finishing of the wood.
It actually worked well for several years until I erred on the side of graduate school and sold the boat.