Masthead lights do not last

Ben and Gayle Super Maramu #347

Since we bought our SM last year (Feb 2015) we've  replaced the anchor light bulb 5 times.  The boat was little used - fewer than 800 hours on engine and generator - and we've  had only the usual maintenance issues which makes this issue most perplexing.  We're trying to determine what could cause premature bulb failures.  I've suspected a bad batch of bulbs; a surge in the electrical when running the generator; or perhaps corroded fitting causing an on/off for the bulb thereby shortening their life. 

Has anyone had a similar experience?  Also it would wonderful to have a source for high quality bulbs.

Ben and Gayle
La Bella Vita
SM 347
Port Louis, Grenada


Hi Ben & Gayle

On Amel Super Maramu the voltage tends to change when using the diesel generator. If using normal bulbs they are usually specified for 24v and have problems when current goes above 26v.

The following alternatives are available:

- buy bulbs specified for the range between 24-30v

- put in a DCDC converter for the different navigation lights

- change to LEDs that are specified for 24-30v. If using LED a DCDC converter is preffered to stabilize the current and protect the life time of the LED.


DCDC converters could be found on the Internet and are not expensive as long as you are not buying units managing 15 A or more.


We have LEDs and DCDC converters infront of all lamps, navigational equipment and compressors. Have saved a lot of time and money!


Jonas S/Y Lady Annila, SM232, 1998

In Portimao, Portugal.