JoeM wrote:I definitely understand the need for a "window" in a plywood hull if you choose to use an in-hull transducer.
After reading through your Overnighter build, I understand why you want no holes below the waterline. You intend to beach regularly. I also would be wary of having a transducer or other appendage either sticking out or get plugged up with rocks and sand.
And BTW, your build looks great! I'm going to keep up with your build!
I personally would still drill an oversized hole, epoxy fill, redrill correct size hole, and install a drain plug. But that's my personal opinion, to each their own.
This next bit i'm not sure of as i'm rather inexperienced in working with fiberglass and resins. Though I have been on both wooden and fiberglass boats and have been able to compare the feel of the hulls, by hand at least. I would also be a little wary of having a super hard area of the hull that won't flex surrounded by wood that will when beaching. I would think the constant flexing would impart stresses on the joint area, weakening it, possibly leading to a failure similar to the shearing off of a thru-hull transducer. I do see that you have both fiberglass and xynel(?) which while giving lots of abrasion resistance I don't know that it imparts enough stiffness to where flexing won't happen at all. And while epoxy is used in laying the fiberglass and xynel, the coats aren't that thick. When you create the "window", isn't it much thicker than the amount layed on the wood and fiberglass? Doesn't that make it much stiffer and more resistant to flexing when compared to the rest of the hull?
I'm in no way saying I'm right and everyone should do what i'm doing. There are so many trade-offs and compromises we each must make in order to reach our individual end goals. Learning from each other's experiences and why they did the things they did can only help us all.
Without going into excruciating detail suffice it to say I'm not the least bit worried about the integrity of the window. In fact, if there were any part of the hull I wanted resting on a rock it would be the window and not a plywood portion of the hull.
The fiberglass window is about 5" inches square. I layed it up to match the 3/8 thickness of the hull plywood. I also installed a plywood flange of sorts that it is bonded too. Then there is additional framing inside the hull supporting it. I wish I had pictures but they were all on my old phone which died not long ago.