Water ballast is a very efficient method of helping the craft to remain upright when forces being applied to the sails can not be converted into entirely forward propulsion of the boat and as a result would cause the boat to heel over until the wind was spilled.
One of the main benefits over traditional heavy keels is the ability to sail with the tanks empty for a more exhilarating sail with competent skipper and crew or to fill the tanks for a more sedate sail should starter skipper or crew be on board.
Another major benefit is the significant reduction in weight achieved by emptying the tanks before winching the boat back on the trailer and towing the boat from the sailing venue.
The design of the Swallow Boats water ballast system allows the tanks to be filled and emptied whilst sailing to adjust the ballast for changing wind strengths. Partial fill of the tanks however is not recommended as the water will move from one side of the tank to the other when tacking creating surges and instability.
Through a method of trial and error, it has been discovered that the best way of emptying the ballast tank in a BayRaider 20 without resorting to a pump is to have three screw-in drain plugs emptying into the aft sump. The bung holes should be large (25mm internal diameter) and placed as low down as possible, one centrally and the others far out to each side. Emptying is further encouraged by allowing air to vent into the tank as it empties. This can be achieved either by keeping the large aft inspection hatch slightly open, or by installing an air vent with a non-return valve into the roof of the ballast tank – just aft of the centreboard case is a good place for this. Once the ballast water is emptying into the aft sump, it can be removed from the boat altogether by self-bailers installed in the bottom of the sump. Recommended are the externally-mounted Andersen models – either the Mini or the New Large. These work quite efficiently once the boat is underway (under sail or power) at around 4 knots or above.
On the BR20, self-bailers installed in the tank itself do not seem to work so well and in addition, those installed under the forward inspection hatches are tricky to operate when sailing solo.
Once most of the ballast water has emptied through the bung holes into the sump, there will be a certain amount of water still left in the ballast tank, probably amounting to around three or four sump’s worth. This can be emptied completely using a pump or sponge through the aft inspection hatch or by the simple expedient of undoing the water inlet plug in the bottom of the tank when the boat is hauled on to its trailer.