Underwater yacht light mounting options

How underwater lights will be mounted is an incredibly important decision and needs careful consideration. There are three underwater light mounting options: thru-hull, electromagnetic induction and surface mounted, however another option may be lighting installed on the transom.

Thru-hull lights

Thru-hull underwater lighting units will require a drilled hole through the hull of a yacht to pass wires and the actual light unit through.

Advantages of through-hull lighting:

• Easy to replace a burnt-out bulb
• Interchangeable. This means the light array can be serviced (removed and replaced) from inside the hull with the boat in the water
• Generally brighter as larger light units can be used

Disadvantages of through-hull lighting:

• Drilling through the hull will be needed
• More expensive than surface mounted lighting

Interior access can prove to be an issue

Induction lighting

Induction operates by having the primary unit (the housing for all the inverter electronics and communication control) on the inside of the yacht, lined up with the secondary unit (the luminaires and drive circuitry) on the exterior of the yacht. Both units are positioned in place by marine grade adhesive. 

Advantages of induction mounting:

• No drilling whatsoever
• Similar water penetration to thru-hull models
• Can be accessed from the inside of the boat

Disadvantages of induction mounting:

• More expensive than surface mounted lighting
• New technology, which means it is untested in general use

One lighting specialist embracing this new technology is BGB SILS. Its marketing manager, James Tupper explained, “Perfecting the induction technology and in particular the moulding of the material for the yacht lights has taken up the vast majority of R&D time.

“It certainly hasn’t been easy but we‘re close to having productionised units ready for real-life testing.  We have enquiries on a daily basis through the website and certainly receive lots of attention at the shows we exhibit at. 

“Our potential customers and test boats have been really patient with us and fully understand that a unique product like SILS needs to be perfected before we dare release it to an industry that seems to be crying out for induction LED products.”

Surface-mounted lights

These types of lights only require a small hole to accommodate a wire and some state of the art units need no drilling at all.

Advantages of surface-mounted lighting

• Cheaper than the thru-hull models
• No drilling necessary

 Disadvantages of surface-mounted lighting

• Surface-mounted lights last only for the light lifetime, so once its dead, you need to change the whole unit
• They generally use smaller systems so not as bright as thru-hull systems
• Difficult to replace/repair

Beam width/spread angle

Another major influence on the amount of light that’s produced is the width and angle of the light fitting.

Spread angle

It’s important to check the penetration angle, the higher the angle generally the more expensive, for example most LED's start at 40 degrees (0 starting horizontally then going down), this will effect the spread of the light backwards and downwards, again, the more the spread is, the higher the price is. 

Beam width

The beam angle of the underwater light determines how the light beam appears around the hull. Available in narrow spot (less than 90°) or wide flood (greater than 90°), it produces an even glow of light and allows lights to be spaced further apart on the hull.

Questions to ask when buying underwater lights

When buying any underwater light there are several questions you need to ask to see which is most suited to your boat:

• What is the beam power in angle degrees and lumens?
• How much power does it need?
• Do you have easy access to your hull?
• Will the light fitting fit through your hull?
• What is the life span of the unit?
• Is it in your budget?

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Discover more yacht lights and lighting tips in our dedicated guides. You can find superyacht lighting and underwater lighting specialists in our superyacht services directory.