Hello Barry,
Sorry to hear this. The keel lifting tackle is more than adequate for the static load of the keel. I imagine the damage yours suffered was inflicted by shock loads. When the boat dries out, it needs either to be on soft mud or it needs totally calm water. If the bottom is hard, such as sand, any swell or chop will repeatedly cause the keel to be lifted in its slot a few inches and then dropped on its strop/lifting tackle. There is very little stretch in the wire strop or lifting tackle, so the shock loads on the components will be high (i.e. the forces are imparted in a short time).
If you beef up the pin, the shock experienced by the strop, lifting eye and deck will be increased.
To reduce shock loads, the strop would need to be replaced by something shock absorbing, such as one made from nylon rope - the longer, the better. However, it would still be undesirable for the keel to be bumping up and down and, in shallower water, the hull will be pounding on the unforgiving bottom too.
I know this is not what you will want to hear because it implies your mooring might be in an unsuitable position. I wish you well with resolving the problem.
Anthony Russell
235/02 Sea Wyche
Anthony Russell
235/02 Sea Wyche