Displacement on large surfaces - ocean scene

The scene below is an ocean scene for a current proposal at university:

http://img65.photobucket.com/albums/v199/simonharvey/ocean_scene.jpg

it is so big that it clips the viewport at 1000 blender units - just to give you a size of scale.
I would like to put a displacement on the ocean surface to get something like:

http://img65.photobucket.com/albums/v199/simonharvey/ocean.jpg

however this is for a little grid patch that had its UV coords over a smaller space. I can get something that looks alright (from the nice ocean view tutorial) but it just dosent look as realistic:
http://img65.photobucket.com/albums/v199/simonharvey/render2.jpg

When I use the method proposed by RipSting this is what I get:
http://img65.photobucket.com/albums/v199/simonharvey/render.jpg

This is with Disp=1.0 - as you can see it comes out flat.

I was wondering how you can force blender to displace the amounts to a value not limited by the maximum amount set by the Disp value.

scale your whole scene down

The contrast of your displacement texture effects this limmit.
The higher the contrast between light and dark, the more displacement you get. With a displacement value of 1.0, you will get higher relief from a
high contrast texture then with the same texure at a lower contrast.

Of course you hit a limmit when you have Disp. at 1.0 and a fully black and white texture.

you know… there is a contrast slider for textures in the texture buttons? on the colors tab [where a colorband could be]…
[can adjust brightness there too]

I just had this problem too. A check of the docs on blender.org showed the way:

Enter edit mode on your ocean mesh. Scale the mesh down (to 25%) within editmode. Leave editmode. Scale your mesh back up 400% in object mode. Do NOT apply the scale with ctrl-A. Displacement size will increase with object level scaling. Keep doing this until it is as deep as you want.

Thanks all,
I scaled the scene down and it worked (sometimes the best methods are the most obvious). I probably wont post a pikkie in the WIP forum because it isnt really an arty thing but thankyou all the same.

Kind Regards
simon