Re: Rigging a Trimaran
The boat looks like a Piver loadstar, around 35'?
You would definitely would want to run the sheet inside the rig and there should be a fitting on deck for a block to lead it to the winch. I would suggest that you check this fitting very carefully for rot underneath and make sure that it has a proper backing block.
What is interesting about a tri is that you can have two fittings, one far outboard and one close to the house (or on it) and move the fairlead block in or out to get the perfect curve on your headsail. Once you get sailing, play around with this idea and have fun. Y'all now have a "stable platform from which to set sails". Enjoy.