What framing do I need to build a garage with 13 ft walls to store a boat?
The most important question here is, 'do you have a building plan?" Building a structure with 13 to 14 foot walls and a 12 foot door is quite a reach for an inexperienced DIYer. You should start by selecting a set of building plans at your local lumber yard or maybe online. There are a lot more considerations than what size studs you should be using. You are going to need a foundation detail to support the added weight of this large building.  The wall details will most likely be 2X6, fire breaks, and 1/2" to 5/8" sheathing, ground built then lifted into place. Your design may use roof trusses or rafters with collar ties, and substantial posts and headers for a 12 foot door.

A building of this size is most definitely going to require a building permit. To get this permit, they will need to see your blueprints or plans.

With all that said, I personally would not build 14 foot walls with 2X4's. I would use 2X6's 16"OC, horizontal stiffeners 48" OC, 5/8 CDX sheithing, double 2X6 plates(upper &amp; lower) and an engineered truss roof. Door headers minimum of 4X12 @ 12 feet, preferably a LAM.