Mahdee’s portholes are a little different than other portholes we’ve seen. First, they are secured with a “cam” system that locks down with the rotation of a single lever rather than the system that other portholes have where there are large nuts that turn individually on screws to tighten the porthole at one, two, three, or more locations. The cam system provides even pressure such that glass shouldn’t break when the porthole is securely tightened against weather.
The other “different” thing is that the portholes are held in place by fasteners through the inside rim only. Going through the hull there is simply a thin-walled tube that extends from porthole itself to end flush with the outside face of the hull planking. Each tube is a different length based upon the thickness of the hull, ceiling, and porthole combination. These thin walled tubes are in poor shape due to almost 80 years of corrosion; so we are trying to find replacement bronze tubing. If we cannot find the large diameter thin-walled tubing, we will have to braze/weld bronze plate into a tube and use that instead. Click on image for very large view of the portholes.