Prototyp på en självrätande katamaran (VIDEO)

Det australiensiska katamaranvarvet Harryproa har gjort några spektakulära byggen genom åren. Nu har dom gjort en prototyp på en katamaran som kan räta upp sig själv när den har vält. Den största nackdelen med en katamaran som nöjesseglare är att den kan välta till skillnad från en kölbåt. Därför hade en design som denna varit revolutionerande.

The video shows a model harryproa being capsized and then re righted without assistance. The requirements for this are:


The lee hull has a false floor that is slightly higher than the waterline. ie when the hull is full of water, there must be enough buoyancy to cause the water to drain out. This buoyancy must be less than the weight of the beams, crew and windward hull. The false floor provides this. It may not need to be full length. There are slots in the hull at false floor level to flood and drain the hull. The larger the slots, the quicker the righting.


The boat capsizes and the buoyant, sealed mast stops it at 90 degrees. The lee hull fills with water and is pushed under by the windward hull and beams. The buoyancy of the mast causes the windward hull and hence the centre of gravity to move away from the centre of buoyancy until it's weight rights the boat, the water drains out of the lee hull and you are sailing again.


A schooner rig would improve fore and aft stability which is poor with the single mast, hence my hands hovering over, but not touching the model. The further to leeward the mast is, the quicker the righting. The model uses open ended hulls for flooding and draining instead of slots.

Capsize movie #1 from Harryproa on Vimeo.