Bow thruster fairing

[Wind River]

I have installed my bow thruster tube and will soon be ready to start the external fairing of the tube.

In the instructions for the thruster it is recommended to add a spoiler along the leading edge of the tube so that when viewed from the front of the boat, parallel to the center line, the spoiler covers the trailing edge of the tube to reduce drag and to keep water from being forced into the tube and possibly turning the props and creating noise.

This spoiler in my case will be about 3 inches out from the hull at its furthest point. Instead of just a spoiler, I was considering making a nice tear drop shape that extends farther forward than a spoiler does. There will be quite a lot of thickness to it and I was going to use Coosa Board to construct most of the shape, then fair it all smooth and cover it with 8 -10 layers of 1708 glass giving a thickness over the Coosa of about 3/8".

Since the Coosa board does not absorb water and will be encased in glass and epoxy, I would think it should make a good filler that will not shrink or crack.

Any thoughts on using Coosa for this purpose or the spoiler vs. tear drop fairing?