6.2. Hulls with Unique Stern Features

For many planing hulls, the aft portion of the running surface is straight, however, there can be exceptions where there is a curvature, angle, or twist just forward of the transom. This may be referred to as a stern wedge, hook, or rocker. These types of features are generally added the hull to improve handling characteristics or induce a constant trim, adding a bow down moment during normal running conditions.

Be sure to use a 3-ft (0.9 m) straight edge along the hull bottom when evaluating the transom angles to obtain a correct assessment of the running surface.

If the Seal Plate were to be installed following the same angle as a stern wedge, it would create a permanent additional upward force in the aft of the boat, and the bow would be pushed down irreversibly. This incorrect assessment for installation is demonstrated below.

Figure 23 – Incorrect Assessment of Running Surface

Measure the angle of the transom over a greater length of the running surface up to 3-ft (0.9 m) to ensure the proper angle.

Figure 24 – Correct Assessment of Running Surface with an Extra Long Straight Edge