Underwater Light Installation Best Practices

Regardless of the size or type of boat, it is obvious that underwater lighting has become a standard tick-the-box item on any new build. Over the years, as adding underwater lighting has evolved, some potential pitfalls have developed that are often overlooked. Many tech related issues can be avoided by understanding the history as well as best practices regarding the installation of underwater lighting.

In the early days, all yacht underwater lights had either HID or halogen lamps. Some were adaptations of swimming pool/submarine lights while a few were manufactured specifically for boating. As the boating product evolved, gradually standards were applied together with testing to determine suitability as official “class societies” became involved. This was a step in the right direction, but as we all know, there was really no standard uniform tests applied since each class society or individual surveyors created additional requirements to meet their interpretation of the class rules. One example of a requirement that was requested on a regular basis, was the use of additional cofferdams to ensure that if the primary or secondary cofferdams failed then there would be no water intrusion. Although this process added cost, required more space and installation time, it was never really challenged.

LED Heat – Critical Installation and Safety Concerns Using Cofferdams

With the arrival of LEDs this practice continued on a sporadic basis. Related issues have escalated to the point where concerns should now be voiced. In contrast, HIDs projected much of the heat generated during use through the lens which allowed the water to help with thermal controls. Although additional installed cofferdams contained the heat it did not become a critical problem. LEDs however, tend to emit the heat produced behind the fixture and lens. Contact with water results in less thermal control. Therefore, placing the fixture in an additional confinement (i.e. a cofferdam) retains the heat with some serious potential problems. These problems range from reduced LED life to fire hazards, none of which are desired. It should also be mentioned that ironically when qualifying for any class approval, no testing involving cofferdams is ever completed. Yacht owners specifying LED underwater lights should ensure that the lights specified have approval without additional cofferdams and verify this with the class surveyor.

LED Retrofit Do’s and Dont’s

The next potential problem results when changing the original lights from HID to LED technology. There are many companies volunteering their products for this purpose which opens the door for potential problems. The main idea of a retrofit is to change technologies while retaining the original thru hull fixture. This appears to be a relatively simple procedure that makes sense, but alas may not be so simple. Compatibility of combining the retrofit with the original fixture may be difficult to achieve depending on the ability of the supplier. Real questions should be addressed regarding less obvious issues that I am sure many have not considered. As previously explained, any installed cofferdams might create thermal problems along with the risks previously mentioned. Regarding most LED installations, the class society should be consulted and the cofferdams removed. Any time class regulations suggest adding a different manufactured product than the original, the complete unit will not be “to class”. While this might not get noticed – why gamble with safety? If that wasn’t reason enough, this practice could compromise your warranty. Obviously, no manufacturer will warranty another company’s product, therefore, it will not take much imagination to guess what might happen if a serious failure was to occur and the warranty was required. The solution is simple, if you are considering changing your yacht’s lighting to LED from HID technology then my advice is to go back to the original product manufacturer and buy from them. Do not believe the wild advertised claims of companies trying to cash in by providing a mismatched solution.

It is far better to be forewarned than sorry later.

I hope this simple article will help you avoid any problems that can result from inappropriate underwater lighting installations on your yacht.

by Ian MacDonald, President of Sea Vision