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#15130
Chris Green
Participant

The hull speed (c6.5 kt)  is relatively high in the Atalanta compared with similar sized displacement cruisers due to the long waterline (c24.5). This in itself makes her faster in a decent blow than many larger displacement yachts with less waterline length and/more wetted area. Reducing weight will increase acceleration up to to hull speed, as will fairing and smoothing anything below the WL. Even though she is already light at 2t (depending on payload etc), it would take much further reduction in ballast (and hull modification) to achieve any chance of true planing – as opposed to surfing and slipping down waves etc.

As mentioned way back in this thread (citing UF’s book “Sailing Boats”), the Fairey built Uffa Fox designed 24 ft “Fairey Fox” (displacement 680 kilos) was a planing design with a superficial similarity to the Atalanta with a waterline of 24ft. This design  could achieved planing with a hull form specifically designed with a long flat run with a chine aft; the flat run began about one third back from the bow. She had only an 85lb drop keel (3/8″ thick) with sharpened leading edge. The drop keel was so narrow it avoided the need for a rubber strip over the slot. So roughly scaling that up to the Atalanta – maybe 50lb per narrow keel! The Fairy Fox also required a crew to provide ballast as on any performance boat – Uffa warns that she should never be taken out with less than four people because of the windage in her topside mast and rigging.