Grand Banks Holding Tank Repair

When dealing with holding tank problems on a Grand Banks, the most likely problem you will run into is a bad pickup tube. The original tubes and fittings were made from copper and it is quite obvious that they will not last. In the picture on the right, you can see the deterioration and how the pickup tube has virtually corroded away.

It would be fairly easy to duplicate the fitting exactly, but would be the sense in that when you know what is eventually going to happen to the fitting. You could build the whole assembly out of stainless, but it would be cost prohibitive. The optimal solution is to build it out of off the shelf PVC sanitation fittings. These are specifically made to work with waste and will not corrode or deteriorate over time.

Another problem you will most likely encounter is bad venting. The original vent lines we see on most boats are too long, too small and make too many trips to places they don't need to go. The best solution when upgrading is to make the shortest run possible with no dips or side trips on it's way to the vent. We also suggest upgrading to 1 ½" hose or at least 1" hose to replace the 5/8" that was original equipment.

You may also consider giving your holding tank a good cleaning. After years of use there is bound to be a fair about of build up in the system, very similar to what you find in the hoses. We installed a Tornado Rotary Tank Rinser by Camco in one boat to keep his tank clean. You can also use some food grade vinegar, which has just enough acidity to do some serious cleaning, but enough to damage the tanks.

With the tank in proper order, it may be time to continue on to hose replacement if necessary. Hey, it's a dirty job but we are willing to get our hands dirty if you don't want to.

Dickerson Harbor
3831 Trappe Landing Road
Trappe, MD 21673
410-822-8556
dickerson@oya.com