8 bags of cement
1200kg of ballast
Lots of buckets of water
2 links of 2" chain
1m steel rod
Take one wooden disc and place on a solid surface. This disc forms a concave base to the sinker helping it to suction onto the harbour bed.
Cover the disc with a sheet of damp proof membrane. Set up the mould around the base and bolt together the two pieces.
Weld the two links of chain to the iron bar and suspend it over the centre of the mold. The iron bar helps secure the links in the concrete mix.
For the next two hours mix the ballast and cement in a cement mixer and pour into the mold. The chain may shift a bit so make sure at the end it is central in your sinker.
Before the concrete dries decorate your sinker with your initials or cat's paw prints. Once it is solid enough, remove the mold and leave in a safe place to set for at least a week.
If you haven't the space or energy to make your own and really want one, then contact Adrian Karn for details of purchasing a freshly made mooring sinker.
Chichester Harbour Conservancy
Harbour Office Itchenor PO20 7AW