CaspersCruiser
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- May 11, 2016
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The anchor light on the mast of many Ranger Tugs is the Aqua Signal Series 25 Masthead 12V. Every once in a while, a question is posted about how to remove the lens assembly on this light to access the mounting hardware, the bulb inside or to check wiring integrity.
The Aqua Signal Series 25 has two pieces, the base and the lens. The base fastened in place on the mast with three screws and nuts. The lens assembly attaches to the base using a bayonet mount.
To remove the lens assembly from the base, push it down slightly and turn it counterclockwise slightly and then pull up. It takes very little rotation to release it, less than 1/16 of a turn.
The tabs on the bottom of the lens assembly are indexed to the base— one tab is larger than the other two. When reinstalling the lens assembly, position it so that the larger tab is aligned with the larger slot on the base, push down slightly and turn clockwise.
Here is the Aqua Signal Series 25 with lens assembly separated from the base. The lens assembly is shown upside down to make the tabs visible.

If you wish to replace the incandescent bulb with LED, here are the two choices:
For made fixtures before September 2010, use this bulb:
https://store.marinebeam.com/30-led-44m ... fs-44-30b/
For fixtures after September 2010, use this bulb:
https://store.marinebeam.com/30-led-42m ... fs-42-30c/
If you’re unsure of the age of your fixture, the only way to tell which bulb your fixture requires is to check the bulb currently installed.
Marinebeam LEDs are more costly than what one finds at WalMart, but they don’t emit RF that interferes with VHF radio and AIS operation. The USCG has put out a bulletin on LED RF interference.
I’m posting this for folks who may search the forum for information about the Aqua Signal 25 in the future.
The Aqua Signal Series 25 has two pieces, the base and the lens. The base fastened in place on the mast with three screws and nuts. The lens assembly attaches to the base using a bayonet mount.
To remove the lens assembly from the base, push it down slightly and turn it counterclockwise slightly and then pull up. It takes very little rotation to release it, less than 1/16 of a turn.
The tabs on the bottom of the lens assembly are indexed to the base— one tab is larger than the other two. When reinstalling the lens assembly, position it so that the larger tab is aligned with the larger slot on the base, push down slightly and turn clockwise.
Here is the Aqua Signal Series 25 with lens assembly separated from the base. The lens assembly is shown upside down to make the tabs visible.

If you wish to replace the incandescent bulb with LED, here are the two choices:
For made fixtures before September 2010, use this bulb:
https://store.marinebeam.com/30-led-44m ... fs-44-30b/
For fixtures after September 2010, use this bulb:
https://store.marinebeam.com/30-led-42m ... fs-42-30c/
If you’re unsure of the age of your fixture, the only way to tell which bulb your fixture requires is to check the bulb currently installed.
Marinebeam LEDs are more costly than what one finds at WalMart, but they don’t emit RF that interferes with VHF radio and AIS operation. The USCG has put out a bulletin on LED RF interference.
I’m posting this for folks who may search the forum for information about the Aqua Signal 25 in the future.