#### Answer

The height of the sail is $14$ feet.

#### Work Step by Step

The formula for the area of a triangle is given by the following formula:
$$A = \frac{1}{2}bh$$
In this problem, the area of the triangular sail is $56$ square feet and the base is $8$ feet.
We can set up the equation as follows:
$$56 = \frac{1}{2}(8)h$$
Multiply, according to order of operations:
$$56 = \frac{8}{2}h$$
Simplify:
$$56 = 4h$$
Divide both sides by $4$ to obtain the value for $h$:
$$h = 14$$
The height of the sail is $14$ feet.