I'm not sure if you have any "Targets" in your area but I just purchased some from there. I think they had white , red and blue in the 12volt. I went the power inverter route because they had purple in the 110volt. I think they had 12' and 25' lengths. They are wired like Christmas lights so one can be plugged into another.
If you cannot find them I could recheck the availability and make a purchase for you ?!
I'm not sure about USCG approved ?!