Overview

The Hella Marine 178560181 is a 12V, 10W clear festoon replacement bulb with an SV8.5-8 base for navigation and interior light fixtures. It uses the double-ended festoon format (about 10 x 41 mm), so it seats in spring clips at each end rather than a bayonet socket. On a 12V DC system it adds a 10W load, which is helpful when you are budgeting lighting circuits.

This is a straightforward swap when your fixture calls for an SV8.5-8 festoon bulb, including many compact navigation lamps and small interior lights. Match the length and end style to the bulb you are replacing, since festoon bulbs come in several sizes that look similar at a glance.

Key features

• 12V DC, 10W clear festoon replacement bulb
• SV8.5-8 double-ended base for spring-clip festoon holders
• Approx. 10 x 41 mm size for fixtures built around the 41 mm festoon format
• Common fit for navigation and interior fixtures that specify an SV8.5-8 festoon lamp
• Used in various compact navigation lights, including Hella 3562 series fixtures that take an SV8.5 festoon bulb

Compatibility and fit

Use this bulb in 12V fixtures that specify an SV8.5-8 festoon (double-ended) lamp. If your light takes a BA15s or BAY15d bayonet bulb, or a different festoon length, it will not seat correctly.

It is commonly found in compact navigation lights and small interior lamps. On boats with a 24V house system, confirm the fixture is fed from a 12V circuit before ordering.

Installation and setup

Shut off the light circuit at the switch or breaker and let the old bulb cool. Open the lens, release the bulb from the spring clips, and snap the new bulb into place so both ends are fully seated. Before closing the lens, clean any salt film from the contacts and make sure the gasket is sitting flat to help keep moisture out of the fixture.

Use on board

This bulb is a good match for owners keeping existing incandescent navigation or interior lights in service and wanting the same form factor the fixture was built around. It is commonly used for small running lights, cabin lights, and chart table or utility fixtures that rely on the 41 mm festoon format.

Maintenance and care

Incandescent bulbs do not like heat buildup or loose contact, so it helps to keep the fixture closed tightly and the terminals clean. Carrying a spare on board makes quick work of an unexpected light-out before an evening run.