Fresh Water Tank Bulging

[Barrie]

My fresh water holding tank in the bow of my 1988 Hunter Legend 37 has a large bulge on its top after I filled it. The bulge was so pronounced it pushed the plywood cover up and through the screws holding it down. No leaks have occured and once I removed some of the water the bulge went down after a day . What would cause this and should I replace my tank now or wait for a leak to occur if now or never.Thnaks in advance

 

[Ken Bell]

Our '89 H37 has the same problem. Although this is only our second season with the boat, there haven't been any negative indications to date (i.e leaks). I try to station my son below to let me know when the tank starts to push the plywood up to let me know that the tank is full.

 

[Randy]

Bulging Tank

Check the overflow vent line. The tank should be properly vented. The vent line may have become blocked.

 

[RON MILLS]

Randy's got it right.

Had the same problem. My vent line had spider webs in it. Ruined the tank from overfilling.