Thats the LR2, sailed by Randy Smythe, designed by Richard Roarke, built by John Lindhal. Ian Lindhad is sailing the same hulls and Fred Smith (Canada) has one also. Boomless main is Randy's creation, I believe.

I cant answer the "why is it shaped like that" part of the question. You could do a search on LR2, I think it was discussed here and on one of the design sites.

Bill