The seal around the water tank in the quarter berth is leaking and needs some special attention. When I purchased the boat six years ago, someone had slapped some fiberglass over the edges. That didn't work. I ground off the fiberglass and sealed it with silicone. This worked for a few years. The problem is that when the tank is nearly full, a good deal of pressure begins building inside. That pressure is pushing the silicone out of the gap at points. The screwed-down lid actually bows outward a bit as the pressure builds. This pressure is accumulated before water exits the overflow at the stern, and appears necessary to push the water up and out the overflow. If I'm going to go back in and replace the seal, I'd like to do it with something that would be best suited for this situation. My thought is that there must be a type of seal I can employ that'll actually get tighter as the pressure builds. Any ideas? Thanks, Scott Fraser Rubicon Key West
Water tank seal?
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We had ours done a couple years ago.
We had the tank on our H'31 sealed a couple of years ago. The problem with our was the fact that most of the holes were oversized and would not make a tight seal regardless of what I did. I finally bit the bullet and had the lid glassed in place. This required that the gelcoat must be ground off. Then it can be glassed in place and gelcoat can be reapplied for cosmetic purposes. This was posted in the Photo Forum.
We had the tank on our H'31 sealed a couple of years ago. The problem with our was the fact that most of the holes were oversized and would not make a tight seal regardless of what I did. I finally bit the bullet and had the lid glassed in place. This required that the gelcoat must be ground off. Then it can be glassed in place and gelcoat can be reapplied for cosmetic purposes. This was posted in the Photo Forum.
There shouldn't be any pressure in the tank
What you call the "overflow" isn't an overflow, it's a vent...While it's ok to let WATER (but not fuel or waste!) overflow out a tank vent, that's not what a vent is for. The vent is supposed to do two things: 1. provide an escape for air in the tank displaced by water when the tank is filled...'cuz if no air can get out, the tank pressurizes--which is what's happening to your tank...what's causing it to bulge. 2. provide a source of air to replace water being drawn out by the pump. If no air, or not enough air, the water pump will pull a vacuum that prevents it from pulling out water or reduces the amount of water while making the pump work harder, which damages the pump. So if your tank bulges, it means the tank is pressurized, it's not adequately vented. So while you may need to reseal the top, you definitely need to fix that. It may be that the vent thru-hull fitting is blocked or partially blocked...or there's a sag in the vent line where water has pooled. Or a kink in the vent line. Whatever it is, if you solve the vent problem and you may not need to reseal the tank.
What you call the "overflow" isn't an overflow, it's a vent...While it's ok to let WATER (but not fuel or waste!) overflow out a tank vent, that's not what a vent is for. The vent is supposed to do two things: 1. provide an escape for air in the tank displaced by water when the tank is filled...'cuz if no air can get out, the tank pressurizes--which is what's happening to your tank...what's causing it to bulge. 2. provide a source of air to replace water being drawn out by the pump. If no air, or not enough air, the water pump will pull a vacuum that prevents it from pulling out water or reduces the amount of water while making the pump work harder, which damages the pump. So if your tank bulges, it means the tank is pressurized, it's not adequately vented. So while you may need to reseal the top, you definitely need to fix that. It may be that the vent thru-hull fitting is blocked or partially blocked...or there's a sag in the vent line where water has pooled. Or a kink in the vent line. Whatever it is, if you solve the vent problem and you may not need to reseal the tank.
Reseal but with 3M marine caulking
Scott, Had the same problem on my 310. The overflow is a result of the head build up during the filling process when the hose from the tank to the deck is still full of water. After using a couple of gallons of water, the problem should go away, but you had the right idea when you sealed it with silicon. I suggest you remove the silicone (which does not stick permanently to the tank) and reseal with a liberal amount of 3M marine caulking like the 4200 or 5200 without removing the screws or gasket. Lee s/v Calaloo
Scott, Had the same problem on my 310. The overflow is a result of the head build up during the filling process when the hose from the tank to the deck is still full of water. After using a couple of gallons of water, the problem should go away, but you had the right idea when you sealed it with silicon. I suggest you remove the silicone (which does not stick permanently to the tank) and reseal with a liberal amount of 3M marine caulking like the 4200 or 5200 without removing the screws or gasket. Lee s/v Calaloo
Very enlightening
Ahhh! A vent, not an overflow. OK, that explains things. I'll be you're right on target with the sagging line holding water, and I'll bet it's behind the fuel tank. That fix sure would be a whole lot easier. Thanks, Scott
Ahhh! A vent, not an overflow. OK, that explains things. I'll be you're right on target with the sagging line holding water, and I'll bet it's behind the fuel tank. That fix sure would be a whole lot easier. Thanks, Scott
Check the photo archives for water tank repair
Steve Dion repair http://www.sailboatowners.com/upload/display.tpl?folder=73224074424&fno=17 My cleanout and repair http://www.sailboatowners.com/upload/display.tpl?folder=Edmundson73107473278&fno=17
Steve Dion repair http://www.sailboatowners.com/upload/display.tpl?folder=73224074424&fno=17 My cleanout and repair http://www.sailboatowners.com/upload/display.tpl?folder=Edmundson73107473278&fno=17
My turn...
This project is now on my list too. My PO must have got a case or two of 5200 for Christmas each year.....it's everywhere, including the water tank. Why couldn't I use SS mig welding wire and make a handle on each end, get the wire started under the edge and saw away? Would the wire clear the top of the baffle? Help appreciated.
This project is now on my list too. My PO must have got a case or two of 5200 for Christmas each year.....it's everywhere, including the water tank. Why couldn't I use SS mig welding wire and make a handle on each end, get the wire started under the edge and saw away? Would the wire clear the top of the baffle? Help appreciated.
Getting caught
The fiberglass lip of the lid's edges are rather thin. My guess is that the wire would cut into it. Especially where there are imperfections in the fiberglass lip, which there are many, especially around the screw holes.
The fiberglass lip of the lid's edges are rather thin. My guess is that the wire would cut into it. Especially where there are imperfections in the fiberglass lip, which there are many, especially around the screw holes.
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