how do you put them under a flush deck? .... I ran my hps about 10-15" above the water with no issues. If a 400 HPS is not enough light for you .... wow lol.

 

I think we need a picture of this setup?

 

^^^^ Agreed. And curious....

 

The deck overhangs the sides a bit. Guess it's not a true flush deck but 3.5 inches isn't much elevation. I never said they weren't enough light it seems like they're so close to the water right now that they're not being as effective as they should be.

 

Then raise the deck and light up to the desired elevation.

Problem solved, please close thread.

 

Wow smart ass much? Asking if there is a more optimal height for lights don't want a raised deck not my thing.

 

The higher the better. Straight down would be best.

Again, without a picture how can anyone begin to help you with your dilemma?

 

If you raise them you'll be able to spot fish future away. Probably won't make a difference directly off the bow.

There is no rule of thumb per say, I personally can't stand knee rails so mine are under my platform.

 

My HPS are between 17" and 20" above the water to the bottom of the housing. I have a flush deck and a knee rail built specifically to set beers on and to mount the lights to. I would imagine at only 10" above the water your light isn't getting much of a chance to spread out so you are getting more of a spotlight effect.
I also built my HPS housings a little longer and wider than they would have to be to let the light spread out more. It seems like the housings I have built that are compact definitely produce a more concentrated output....

 

 

don't think many would attempt to mount lights under gunnel rail on the outside of boat witch I'm guessing is what you have done.

 

Thanks fellas expected a bit more spread based on running them on the trailer. Swapped em to the top of the deck, just waiting on the water to clear up and two more housings to be done.