If there is water inside, you should be concerned
The rudder on the 272 is made by Foss Foam and is supposed to be neutrally buoyant. It is never good to have water where it is not supposed to be because of the damage it could cause. You mentioned the possibility of the water freezing. That is definitely a no-no. The expansion could crack the fibreglass and will probably distort the shape of the rudder.Even if it wouldn't freeze, the extra weight of the water inside will affect the trim of the boat. I would definitely be concerned about the penetration of the water. It may be leaking in at the location of the lower pintles. Check there and at the seams on the front and rear edges of the rudder for cracks.Solution? First, I would suggest weighing the rudder so that you have a baseline for comparison. Hang the rudder inside in a warm place like a basement and drill holes at the bottom to drain the water. If the rudder sounds hollow, there could already be some separation of the fibreglass and foam inside the rudder. Help the rudder dry out by applying some moderate heat from a small space heater. You should keep the heat high for a few weeks, but just high enough to evaporate as much of the water inside as you can. You don't want to distort the rudder with heat.After the dry-out, weigh it again to see how much water there was inside. Now the guesswork begins. You probably will not ever get all the water out, but if the rudder will float, you are back to neutral buoyancy. Repair the holes you drilled and any others that you may have found during your inspection and seal them with epoxy. Use the rudder next season and check your repair at the end of the season by weighing it again. If there is no evidence of water and the weight is the same, you should be ok. I don't think I would store the rudder in a cold area because of the water that may still be inside it. Freezing could mess up all your repair work.Is all of this worth it? It's up to you, but a new rudder is expensive.Tom