we have a leak in the water tank of our Californian 45. Started as a small trickle. we can still can keep water for three or four days. It appears to be from the bottom which is out of site. One boat mechanic has recommended opening the top via the hatch at the foot of the cabin berth and spraying some type of sealant and or taking out the washer, creating a hatch and approaching it from the front of the tank.Has anyone dealt with this issue? OB