Adding a Holding Tank
I added a holding tank to my 1980 Mk1 Griffon back in the winter of 1999/2000 but several owners have asked for details, so here you are.
Where to put the Holding Tank
There is not much room in the Griffon's heads but there is a suitable locker next door in the fore-cabin. The locker is an awkward shape, so I made a cardboard tank and adjusted it to fit, then created the drawing from which the tank was made. To save anyone else going through this, here is the drawing I created (please check that it will fit your Griffon, just in case....).
How to fit the Holding Tank
The holding tank was manufactured from plastic to my drawing by Tek-Tanks but it could equally well be made from stainless steel.
The only way that I could think of to fix the tank in position was to use spray builder's foam, which you can buy from B&Q etc. The tank is very securely held by the foam and is still held fast after 14 years. Inevitably you get excess foam but it is fairly easily trimmed with a carving knife once it has completely set.