[Chris Burkard]

The Tiara 3500 Opens with diesels are bit noisy compared with their modern counterparts. The two things that will make the largest difference is the insulation already mentioned and the second is the hatch gaskets (main and inspection). These are rubber/neoprean gaskets that make the seal when the hatches are closed. The main engine hatch gaskets are flat I believe and the inspection hatch gasket is a D shaped rubber/neoprean. After a while they can get crushed, cut or come unglued. Buy new gasket material, remove the old ones, clean up the old glue residue with adhesive remover and glue the new gaskets in place. This should make a bid difference. Good luck!