Rotten mast foot. Not an unusual sight this Mizen mast with a badly deformed foot caused by sitting in its holding slot in a pool of water. The end grain absorbers the water, the Spruce is very soft and light and consequently deteriorates, with the movement of the foot in the slot it wears away the soft timber end. The smaller it gets in the slot the more it wears away the fibre. Solution, reshape the end, firstly cutting back the soft rotten end and re profiling it. My advise if to drill a few 8 mm holes in the base of its holding slot so water is not trapped and allowed to form a captured pool of water.
The Mizen mast is now cut back and re profiled so it’s a good fit into its slot.
With the foot of the Mizen mast sanded and dry, it being dry is so important for this next process, mask up the top of the area to be primed. Use an oil based primer thinned with white spirit, give it 4 to 6 coats so the primer is absorbed into the end grain, rubbing back with 180 grit paper between each coat. Then apply 3 to 4 finishing coats of a good quality oil based Gloss exterior paint, again rubbing back between coats with 180 grit paper.
To finish off this process form a straight whipping to take up the slack in your Mizen mast step.