The information provided is for a 2002 Duffy 18' Classic. Many systems and components are common across models and years.
It is up to you to determine if this information applies to your boat or not.
The original parts are "Perko Surface Mount Dome Light - 5" O.D. (4" Lens) - Chrome Plated. Part #0300DP1CHR".
The original parts are "Perko 1044DP1WHT White Flush Marine Utility Light with Snap on Cover". Shoreline Marine makes a non-dimmable LED replacement (Part #SL91504), but it will not work with standard Duffy wiring which runs all interior lighting power through a dimmer.
The interior lighting has a common negative and a switched positive. Most dimmers will not work with this arrangement as they require isolating the negative side of the circuit going to the lamps. For this reason, you need a dimmer designed for RV or Marine purposes where a common ground is normal.
Our boat has an Imtra ILDIM-ROT10 dimmer, which has a panel-mounted potentiometer wired to a dimmer box. It is expensive (~$75), so you may want to look for another alternative. This dimmer from PCA Electronics is advertised to work with the lamps on either the positive or negative side, so it should work (I have not tried it). I don't know the diameter of the panel hole, which you should note when ordering a replacement part.
The power requirements for our dimmer are modest.
Light | Volts | Amps | Watts |
---|---|---|---|
Dome 1 | 12 | 0.94 | 11.28 |
Dome 2 | 12 | 0.94 | 11.28 |
Companionway 1 | 12 | 0.25 | 3.00 |
Companionway 2 | 12 | 0.25 | 3.00 |
2.38 | 28.56 |