Thanks 37Pacific. I wonder if most trawlers (or boats in general) have these seals? I've always thought that water was kept out of the boat because of the tight packing material forced tight by the packing gland collar. Can anyone shed light on this? It is important because several people have commented that the shaft log, cemented or glassed in tight, could be failing due to material/bonding failure of the log where it enters the hull, none mentioning "seals."