Kayak fishing can be an awesome hobby if one can afford it. To most kayak fishermen, the kayak is a black hole to sink funds into. Accessories such as lights can be quite expensive.

In this instructable, I'll show you how to make your own.

Step 1: Have a Plan

While purchasing a kayak can be pricey, other options don't have to be. Seeing as though I already owned a cordless 18volt battery power tool set with two batteries I saw no reason to purchase a "kayak battery." With modern technology such as LEDs, these batteries can run longer than most can fish or kayak (present company excluded).

In the pictures above, I used simple math to calculate necessary resistors and battery life. For those of us who aren't mathematically inclined, I've posted a link below.
http://led.linear1.org/led.wiz

The LEDs I used were 3.2 volt Green Microtivity LEDs with forward current of .024 amp or 24 mA. If you take your battery amp hours and divide forward current of the LEDs you will get hours of run time.

In other words my 2.4 amp hour battery divided by .024 equals 100 hours. Remember thought that at certain low voltages, batteries tend to sustain damage and at hour 80 my battery would not be as bright.

Note: It's best never to fully discharge a battery!!!

Step 2: Gather Supplies

Soldering Iron
Solder
Perf board
Diode to protect from spikes in power (optional)
LEDs (number depends on battery voltage
Bracket for mounting on Kayak
Appropriate Resistor
Breadboard for testing
Polyester Resin for waterproofing

(Note use a good quality LED since we will be sealing them in resin later.)

Step 3: Testing

The testing stage.

It's best to test out the setup on a breadboard first. The first time I made an LED replacement bulb there were factors I never considered like heat. The resistor in the picture above started smoking. Had I encased this circuit in resin, I would have invested a lot of time and resources for nothing.

Step 4: Build the Circuit.

Solder all components in place starting with the black and silver diode.

After the black and silver diode add the resistor. Be sure and connect the negative to the resistor and LED1's positive to LED2's negative and so on.

Connect the silver side of the black and silver diode to the black wire and the last LED connector to the red wire.

Color coding will make this easier.

Note: Current through LEDs only flow in one direction. A mistake will render this circuit worthless.

Step 5: Encase in Resin.

Once you know the circuit works, find a suitable plastic container to house the resin. I used a clean cheap ketchup container from a local burger restaurant. Cheap plastic containers such as this one are "oily" and separate from the resin easily when cured.

I used tape and a soldering stand to hold up my circuit while the resin cured around it.

Note: Be sure the circuit lines up or the lights will forever be crooked. Also, be sure the bracket is on the end of the resin case so it can be connected to the kayak later.

Step 6: Remove

Remove from the container after resin is completely cured. Removing prematurely will allow your finger prints to be impressed upon the soft resin or messing up the build altogether. All resins have different curing times so consult your resin for the appropriate curing time.