All ships lifeboats had plugs in the bottom to allow water to drain out (do not remember the word bung used much). Also offshore TEMPSC (totally enclosed motor propelled survival craft) since they need to be ready instantly, are too big to turn over, the if full of water would be too heavy to lower and not usable for survival. Offshore and at sea water penetrates where you dont want it so the plug is vital. Part of drill is to check the plug is in as well as all the other actions that need to be carried out as part of a safe launch of any boat.
When out in Espiritu Santo an excursion was made in the ships lifeboat across the lagoon and the bottom bumped on the coral knocking out the plug. No one could put the plug back in so we arrived waterlogged back at the ship with the engine flywheel spraying water out either side and me on the bilge pump.
In my day the lifeboats were fibreglass so no problems with wood drying out however they had covers to keep out the worst of the weather. Once I went offshore the survival craft were lifeboat hulls closed in making the TEMPSC.