yeh i was thinking of just gluing them in place with gorilla gel superglue, will the heat not make the glue come loose or will it be fine?
The nice thing about LEDs is that they don't get hot. Those with a built in regulator will probably have the regulator generate heat, but the actual LED mostly just gives off light very efficiently, whereas an incandescent bulb generates heat in order to give off light.
Mostly, when building a panel, the trick was to rely on the close fit of the LED in its hole plus the natural springiness of the wiring pushing it in against its shoulder.
Are we talking nav lights or deck lights? On the real thing, nav lights are rarely bright, and can be difficult to spot on a ship with a lot of lighting. OTOH, (on a smaller scale tug), standard 5mm red, green and yellow LEDs running at about 10-15mA were quite visible in the dark at 30+ yards. Yellow because white was in the future back then.
Edit - looking at the boat again, 3mm LEDs. Although naturally inclined to chuck most of the light out of the domed end, they were either painted or mounted in an enclosure so that they were viewed from the side. If the reflecting surface is not light absorbing, the light rattles round until it finds a way out.