Reference is needed for the sails, mast, and sailor. Reference for the sails and mast are found in books. The reference basically just shows me how they are made, the actual perspective for the sails and mast will have to be constructed by traditional perspective drawing methods.

To get good reference for the sailor, I buy a captains hat, find a stripped T-shirt in my closet, then have a friend photograph me at several angles, all of which are similar to the angle in the layout.

Shooting your own photographs gives you much more control than when trying to work with stock photos, it may even be faster! How long would it take to find a stock photo of a sailor, looking up with the sun pouring down on his face, and at that angle? Well. . . how long?

By photographing the reference myself, I was also able to place the yard light in the photo, which would be a tremendous help when figuring out the perspective for the sail and mast.