What is the correct procedure for mounting a thru-hull fitting?

Mounting a thru-hull fitting requires careful consideration to ensure a secure and watertight installation. The most appropriate procedure involves adding a doubler to restore the material that was cut away when the hole for the thru-hull was made. This is vital because removing material can weaken the structural integrity of the hull. By using a doubler, you are effectively reinforcing the area, ensuring that the fitting is supported adequately. This additional layer provides enhanced load distribution and helps mitigate the risk of potential leaks or hull failure due to stress concentrations around the fitting.

The other methods either compromise the installation's integrity or may not provide the necessary support for the fitting, which is why they are less suitable for mounting a thru-hull fitting. Adhering directly to the laminate without the additional support could lead to failure under pressure or structural loads, while using screws alone would not address the potential for water intrusion and weak structural connections.