Mike, the answer to your question....
is that the water in the bilge DOES contribute to blistering, and more critically than you may think. As the Interlux research tech explained it to me, the "top" layers of bilge laminate are much more likely to be roving than mat (which is used on the outside surfaces of the hull to minimize "print through"), and roving "wicks" the moisture to the rest of the laminate much faster than mat. Additionally, if the water in your bilge is fresh water (and your boat lives in salt), there is a higher difference in osmotic pressure. In other words, the process of osmosis depends upon the presence of different fluids on either side of the "semi-permeable membrane", so different fluids promote the process. By the way, draining shower water into the bilge is a bad idea for many other more basic reasons than blisters. And, the best solution I have ever encountered to ice box water was a vertical PVC tube mounted in the corner of the ice box, in which sat one of those piston type moveable bilge pumps. The bottom of the PVC tube was open, and from time to time the boatowners would simply flip the exhaust hose from the little pump over into the sink and pump the box dry. Of course, the normal drain hose had been eliminated, which also eliminated a pathway for the cold air of the box to escape. And finally, although some water will inevitably find itself into the bilge, if you eliminate the major contributors, it is not hard to use a hand pump followed by a sponge to get it out. Just cut a hole in your floorboard over your bilge pump, install a tranparent inspection port, and you now have a way to check the condition of your bilge, clear the pump if necessary, and mop or pump out the residual water. Best of luck.
