High Power 1 Watt LED

I am looking to create a forward spotting light for my boat it will be integrated in to the hard top the size of the pocket is 6" wide, 3/4" high and 1-1/2 deep. the power supply is standard 12 volt dc battery. i plan to wire 4 high power 1 watt led in series. the questions are do i need a heat sync and if so i will make out of alum but i need to know how thick it needs to be.
I do not have a location to mount the High-Intensity LED Flood Light. any other advice you wise to give would be helpful.
thanks - by Timothy (United States)

For wiring in series, for longevity and durability, you'd be better off using a voltage regulator / LED driver for each one, and then wiring them in parallel. Our 1 watt floods and spots already have an LED driver built in, and their aluminum case acts as a heat sink. The prewired superflux 4 chip or the modules would be a good choice, wire them in parallel:
https://www.oznium.com/led-bolts-prewired-leds/prewired-superflux
https://www.oznium.com/mini-led-module

What resistor do I need to use (resistance ; rating ) to power a single LED with 3 D-Size batteries..? How much time would the batteries run..? - by Sai

Have you checked out our LED Resistor Calculator? It may help.

To then calculate how long the batteries would last, you'll need to figure out how much current the LED and resistor draws, as well as how many amp hours your D-size batteries provide.

For how much time does one LED of 1W run on 2 AA batteries without any resistor or any device between them ? - by Sailendra

2 AA batteries does not provide enough power to run the led. One AA is 1.5 volts.