Why does this float script work in studio but not ingame? My title is specific

The script makes an R15 player float on water, but you just get trapped beneath the surface. The game has filtering enabled disabled by the way.

function onTouched(part)
	if part.Parent ~= nil then
		local h = part.Parent:findFirstChild("Humanoid")
			if h~=nil then
if  (h.Parent.UpperTorso.Velocity.y < 5) then
h.Parent.UpperTorso.Velocity=Vector3.new(0,h.Parent.UpperTorso.Velocity.y+.7,0)
wait()
end

			end			
	end
end

script.Parent.Touched:connect(onTouched)

Thanks if you can help me.

Vector3.new(
    0, 
    h.Parent.UpperTorso.Velocity.Y,
IDK WHAT Z WAS 
)

Format line 6 like that to make it readable.