You will need simple native trainer installed..

All you have to do is put objects.ini file into your main game directory.

Use getalife or rotterdam but not at the same time.

for me it's C:\Program Files (x86)\Rockstar Games\Grand Theft Auto IV

Now run the game select trainer using f3 or f4 goto Object spawning
scroll down on the left hand side and the 7th one up load objects.ini.
Now you'll drop into the water and the ramp will load

have fun

