"Plink" or "Plunk"?

    

Installing Masina 'Afa LED Lights
Into Individual A-S Series 41
Side Light Fixtures


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Aqua Signal has made several changes to their series 41 running lights (they've made this lamp fixture for at least 30 years!), so the process of replacing them will vary. This particular essay is for the newest ones, with an internal, stainless steel reflector, tack welded the the stainless steel back. On some, this plate is painted a flat black colour.

The easiest method to determine which you have is to pull the incandescent light from the fixture and tap the top, inside, surface with a screwdriver blade. If it sounds like a metallic 'plink', it's this version, if you hear a softer 'plunk', you can just pull the entire back of the light fixture off more easily.

I'm illustrating the starboard lamp, the port, and stern, lights are done the same, only the colour of the lens, as well as the amount and sector of light masked off differ.

PS: It's usually a good idea to read a set of instructions all the way thru before starting work; on this light, it's even more important!
Series 41 Aqua Signal Side Light Fixture Before Dis-assembly-Click to Enlarge
After pulling the light off, the bottom two screws on the stainless steel back need to be removed.

Removing Back from Lens of Running Light-Click to Enlarge   Removing Back from Lens of Running Light to Install LED Replacements-Click to Enlarge
To remove the back from the navigation light fixture, you'll need to carefully pry the base away from the rest of the fixture.

Not shown in a photo is to stick your finger thru the hole in the bottom (plastic) plate, and to scrape away as much of the RTV silicone that holds the lens to the bottom plate as possible (as you feel the voids with your fingers, you'll realise why the fixture used to leak like a sieve!).

Next, starting on the side with the most metal and closest to the stainless steel back, gently pry the lens from the bottom plate, alternating over to the other side (least metal). Work slowly 'forward' (towards the centre bottom of the lens), until the silicone is loosened within about 25mm (1") either side of centre. Do not rush this part, or try to pry it all of the way off (yet).
 
Click to Enlarge The reason for the caution, (and not prying all the way forward) is What you're trying to do is to seperate the plastic bottom from lens, without breaking the plastic tab located on the center bottom of the lens off.
 
Modifying Running Light Plug to Accept an LED Replacement-Click to Enlarge   Modifying Running Light Plug to Accept an LED Replacement-Click to Enlarge
As you are working the bottom from the lens, give an occasional pry forward from the stainless back plate against the bottom. When it gets loosened enough, the bottom will pop off the plastic tang on the centre forward part of the lens.
 
Now that the light is apart, assemble the Masina 'Afa to the spacer with the three provided wire ties, and using an adhesive, such as Selley's All-Clear or 3M 4200 between the light and the spacer. Modifying Running Light Plug to Accept an LED Replacement-Click to Enlarge
 
Assembling a Side Light After Installing an LED Bulb-Click to Enlarge Put a bead of adhesive around the hole...
 
...and glue it place, ensuring that the coverage sector of the light conforms with the 'mask' of lens of the light. Assembling a Side Light After Installing an LED Bulb-Click to Enlarge
All thats left now is to re-glue the bottom of the fixture back onto the lens and re-install the two stainless screws. For an adhesive, I'd use something not quite as agressive as the Selley's or 4200, RTV silicone as per the original will work fine.