Early designers used the amas as training wheels.
Modern designers use the center hull as reserve floatation.
No-one has yet performed comparative tests to put any real science into the issue. My previous attempts to get input from this forum have been rebuffed by elitists. The bad taste left from multihull purists with closed minds impelled me to buy a monohull, so I don't have to deal with elitists' on the water. I still think trimarans are an excellent idea, if only the voodoo can be taken out of the design process. Help is requested.