Building a new Catamaran Beam From Scratch (Sailing Yes Let's E16)

I discovered a soft spot in the forward most beam. The fore stay is attached to this, while loosing this wouldn't immediately sink the boat... I'd rather not worry about loosing the rig either so I decided to rebuild it from scratch!
I wanted to see if a fiber glassed, hollow box beam could be lighter and stronger. I'd never made a spar like this before so this was a learning opportunity!