If you do not have a vertical surface to attach the V-Lock base, this is the answer.
These shims or wedges are in the shape of the V-Lock base and are designed to adjust the alignment so that the base is vertical.
They are made of Starboard* and come in 3 sizes.
The smallest is 4 degrees, medium is 7.5 degrees and large is 11.5 degrees.
Thickness at the top of the wedge: SM 1/4" MD 1/2" LG 1"
They can be combined to make up larger angles, so if you needed to make up about 20 degrees you would use a combination of a medium (7.5) and large (11.5) to make 19 degrees. Well I guess you would still be off by 1 degree, but you are close!
There are no holes drilled through the wedges as our experience and that of some customers advise drilling through the V-Lock Base, the wedge and boat all at once.
*Starboard is UV Inhibited high density poylethylene (HDPE)