Over this past summer I did a couple of overnight sailing trips in the Sea Rabbit. Federal regulation mandates that any anchored boat must have a signal light on top of the mast at night; law which conflicted with the fact that the Sea Rabbit has no electrical system whatsoever.
For more information on the federal requirements for recreational boats please go to:
Well, in order to do follow the law I decided to hack up something really quick. My plan was to built a light that could be raised using the halyard since we only need the light when the sail is down. It also had to be visible 360 degrees around, as well as last at last a couple nights on one charge of battery.
The solution was to build the following:
Removable Anchor Light
The center point of the light is connected to halyard so it can be raised to the top of the mast. Once that is done the black line attached to the bottom can be pulled tight and secured in order to keep the whole system upright. The white wire is connected directly to the battery. The LED housing contains a small piece of white LED strip ( 3 watts per inch) and it is even a little too bright for the job.
The main purpose for the metallic tape is for heat dissipation, although it also helps reflecting some of the light in the right direction. The power wire comes up through a hole on the opposite side of the PVC pipe and is soldered into the LED strip. I used an acrylic tube with a glued end piece to form a weather proof protection cup, the tube was just the right diameter for a tight fit.
I also added a cabin light:
Sea Rabbit temporary cabin light
The cabin light is also made with a piece of waterproof white LED strip. The LED strip was glued into a aluminum U-channel for heat dissipation and to block the light from coming out through the sides and blinding anyone on the boat. The aluminum channel was then glued into the structural column on the center of the boat using commercial grade double side tape.
The anchor lights consumes around 250mA @ 12V, while the interior light consumes around 500mA. With the 12V 7Ah (Amp-hour) battery I am using I should be able to keep the anchor light running for 28 hours, or the inside light running for 14 hours straight with one charge. If I keep the cabin light on for 3 hours and the anchor light on for 8 hours each night the battery should last me 2 days.
During the overnight trips we did over the summer the lights worked like a charm! It was a very simple and practical solution which I do recommend if you are in the same situation.
The obvious next step is the project I am currently working on: build a wind turbine to charge the battery on the run.