Replacement Knobs for Gebo Portlights in the USA

Admittedly this article has a bit of a narrow audience. But if you've found yourself here, hopefully you are:

1. Looking for replacement knobs for your Gebo Portlights that have probably started spinning on themselves or otherwise corroded to unusable

2. In the USA

These Gebo port light knobs are not a great design in my opinion. Once they start corroding and get hard to spin, they often break. And they can be a huge pain to get off!

I've had to cut a few of them with a Dremel and then use vice grips or pliers to spin off the threaded insert. This often happens after the boat has sat in a yard getting work done or stored over the winter.

Replacement knobs can be hard to come by. I have ordered a few from European or UK websites and had to pay high shipping fees. Often this isn't even an option if we are cruising and not at the same address long enough for the shipping window.

Off to the interwebs for a different solution. and I actually found one at McMaster Carr.

Knobs replacements arrived from McMaster Carr

I measured the Gebo knobs to be M8 thread size, and McMaster Carr has a number of knob options to choose from in that size. I suggest you get the 39mm width, 5 arm grip. I originally purchased the 57mm width, and, while they fit fine, they were too chunky.

The threaded insert on these knobs are made of zinc coated brass, so it will not damage the stainless threads on the Gebo port light. If you ever have to replace those threaded bolts--they call it the spindle--it can be quite the project due to corrosion.

The only down side from the original, if it is really a down side, is that there is no stopper to keep someone from screwing them all the way off. I haven't found that this is actually an issue, though.

Knobs view from above

I first found out about McMaster Carr from an Aerospace buddy of mine many years ago. And I find it the only reliable source for well priced, marine grade replacement parts. I have also purchased many 316 stainless pieces of hardware to fix things like hard to find Lewmar windless bolts. If you can figure out what the head type is called, you can almost definitely find it on McMaster Carr.

Side note: I am not sponsored or affiliated with McMaster Carr in any way, just an admirer of their selection and user experience!