For this kind of application a 3 watt I don't see a purpose.
I am at 84 seperate connections, resin impregnated, SO FAR, on my Akula, with 16 LED lights out of 20 on there now. All of them are not even in a watt range, but milli watt, except one. The flashing 5 mm LED on the marker bouy is a 2 watt. And I had to use a pretty big resistor for that dude too!
Truth is, on my 12 volt boat, I have set all the LEDs to a 12 volt system, but have been "testing", as I go along with a square 9 volt battery, and the LEDs actually are over bright! No heat generated anywhere in the system, either.There will be no loosing this one at night.
If you go to the thread for my build, you will see I used computer cable for wiring. Now that was a spiffy idea. I stole it from my static Enterprise build (which I instigated Steve to do this one from). I had obtained a superdetailing book for the Enterprise which gave me the idea.
At the local computer store, the owner was telling me other modellers do this also, and he felt like you could run somewhere around 5 LEDs on a ribbon circuit because they draw so little.
The whole idea is LEDs are super durable, last forever, can be shaped (to a point),and draw a fraction of what incandecent bulbs do.
With 20 lights total on the Akula, I have calculated the draw and it is negligable to my run time.
Something not yet touched on that was in the same superdetailing book is fiberoptics.
Useing fiberoptics in conjunction with LEDs can really streach your mill amp worth out of a project!!!
The possibilities are pretty cool. With the eight 5mm LEDs in the front of mine, It loooks like a mag light in the dark, for sure, no heat, and under 3 watts easy.
But as a spotlight,searchlight, or something, that could be the way to go using the LED Maglight head. Other than that, though, for submarines, I would say look at the lower draw options and take advantage of what LEDs can do.
SubCommittee Vice President 2006-2008
Author-Russian Submarines, Guardians of the Motherland
Member-Saint Petersburg Russia Submarine Club