Thru-Hull Fittings in Sandwich Construction

Through-hull fittings often introduce localized loads into sandwich panels, which are particularly sensitive to localized loads. In order to prevent damage due to these loads, the panels need to be constructed in such a way as to distribute the loads over the structure in a manner in which the sandwich panel is not damaged.

There are a number of ways to distribute the loads introduced by through-hull fittings.

These include using a high-density core, tapering the core to a solid skin or filling the area with reinforced putty.

If high-density plain Divinycell or Klegecell PVC foam core (> 130 kg/m3) is used throughout the panel, it is generally not necessary to modify the panel. A hole should be cut for the insert and the resulting edge should be sealed with a standard polyurethane or epoxy sealant. The fitting should be installed using a standard polyurethane sealant.