The last sailing trial on my WRC6800 catamaran was March 2006, when I broke its kickup rudder after being driven backwards by gusty winds into a muddy bank, whilst trying to retrieve my hat-overboard. This happening lead me to developing a rudder and centreboard which kicks-up in fore and aft directions - its concept is shown in DRG 1.
Since then I have been trialling the concept on a proa which I constructed using a hull I designed as a centrehull for the WRC 6800 catamaran - Photos 1-3.
This centrehull was created to provide sitting accommodation in the cabin of the catamaran - its concept is illustrated in the Dec. 2003 Installment. I completed building it last winter using a method of hull construction which is relatively simple and lightweight compared to that of my existing WRC6800 hulls. I am presently considering adding this centrehull or a Dory-type hull to the catamaran bridgedeck.
I have reached the stage with this project of wanting to finish it and just go sailing. So I have decided to limit experimentation to developing comfortable on-board accommodation for the WRC6800 catamaran.
I am seeking help in finding a sailmaker willing to make two sails for my catamaran.
Photos 2&3 shows details of a fore-and-aft kickup rudder and centreplate which I am developing for the catamaran. They are mounted on a proa to simplify the development. Photo 1 shows one of the proa rig used in the trials during May which started with a 5sqm sail and a steering oar, and progressed to smaller sails, a spade rudder and steering paddle.
Photo 1 - The proa used in the May 2006 trials.
Referring to Photo 1, The outrigger is a wave-sailboard hull and the structure attaching it to the crossbeams is a quickfix which facilitates changing the board's planning angle and transverse tilt. Notable outcomes of the trials were - the proa was more manageable on the tack with the sailboard to leeward and it appeared to develop adequate lateral resistance - showing good potential for a trimaran using two sailboards thus negating the need for centreboard/fins. On the other tack the proa produced large weather-helm caused I guess by the centreplate positioned to far forward; and the steering oar was found to be very ungainly. Add to this scene, the threat of capsizing the proa in the unpredictable winds of the river and it is not surprising that these trials were non-productive. So I have mounted an outboard on the proa and aim to concentrate first on developing a functional rudder/steering paddle using outboard-motor power instead of sail-power. I favour the steering oar/paddle because it can be used to row the catamaran to assist tacking - and provide a means of propulsion when the outboard motor fails.
Photo 2 - Note the spade rudder and steering paddle to be trialled
Photo 3 - Note the kickup centreboard - and the hole in the topside allowing the option to be repositioned 300mm forward.
DRG2 shows the centrehull concept based on a transon-stern centrehull. I have delayed adding this centrehull to the catamaran because it may result in adding to the catamaran, the objectional transverse flip/flop behaviour of a trimaran. This tendancy should increase as the buoyancy of the centrehull increases. Reducing the buoyancy by reducing the length of the centrehull is not an option because it would increase its wave-making drag (the centrehull shown in photos 1-3 is 4600mm long and its waterline beam shown in DRG 1 is 460mm which is a 10:1 length/beam ratio). So I am considering a Dory-shape centrehull of comparitively lower buoyancy and which would add lateral-resistance facilitating sailing in the shallow water of inland waterways.
Photo 4 - the centrehull
Photo 5 - showing the plug and mould for used to manufacture the GRP end-sections of the centrehull.
Photo 6 - December 19, WRC6800 on its mooring waiting for wind. Note the cabin extension and flat decks. The window is a quickfix insert.
