Vector3 Makes the ship get flung?

I've been trying to code a sinking ship, still not done yet, im working in the moving part.

Although, when i click the button to run the script, the thing nopes out of there and goes into low earth orbit. Anything i need to change?

local ship = script.Parent
local PP = script.Parent.PrimaryPart

function sink()
	while true do
		for i= 1,1000000 do
			ship:SetPrimaryPartCFrame(PP.CFrame * CFrame.new(PP.CFrame * Vector3.new(0,-0.01,0)))
			wait()
		end
	end
end

game.Workspace.button.ClickDetector.MouseClick:Connect(sink)