Hello Paul,
It is common practice on our boats to only block the forward end of the keel, under the actual lead. Reported experience is that blocking under the bilge area is a no no. This area is too weak to take the weight of the boat and will very likely break if the full weight of the vessel is upon it. I have pulled my boat once, and supported it at the very forward end of the keel only and everything was just fine.
David
Blue Moon, #189