MORE THAN TWO TONS of mild steel are forged into the Rother's ballast keel.

Together with such heavy members as the twin diesel engines, set low in the hull, the purpose of the ballast keel is to lower the centre of gravity of the boat and thus increase her stability. Acting like a pendulum, it helps counteract the effect of wind and waves on hull and superstructure; the greater the heel and the higher the keel is lifted up through the water, the greater will be the force of the righting lever bringing the boat back on to an even keel.

Before the ballast keel can be slid into position under the hull the blocks on which her centreline structure has been resting must be moved. So blocks are now built up under her bilge keels, port and starboard, which will carry the hull weight. These bilge keels are cut from 6in x 3'/2in x 3Ain mild steel angle and bolted on with '/2Jn galvanised aluminium bronze bolts; before finally being bolted into place the bilge keels will be galvanised.

The ballast keel is fixed with 38 3mm bolts of varying length depending on the depth of the centreline structure through which each has to pass: forefoot, hog or deadwood. Those going through the deadwood are the longest—the one furthest aft being no less than 3ft 6in long—and, to give room for their holes to be drilled and the bolts driven through, the stern of the boat has to be jacked up as shown in Fig. 2. Each bolt has a countersunk head with a protruding key which, driven up into a prepared groove, prevents the bolt from turning.

(To be continued).