I test drove a 2001 35 Lightning. When in reverse coming off the lift the rear was very loud. The owner said it’s because the swim deck is a void; which I know. Is the sound vibrating in the space causing the lpud
vibration noises ? I’m coming from a Donzi and Sunsation before that. Any help is appreciated.

Some fact some have this annoying vibrating noise... chriscraft stinger was also like that...
thames the dry bark but makes for a low sound /big vibration sometimes...

It’s the top and bottom vibrating where they meet behind the rubrail. It’s a easy fix. Pull the rubrail and load it up with 5200 And put some big aluminum rivets to help hold it while it drys. It’s not glassed together back there.

My 02 35 Lightning sat up in the water, much higher than a 32 (rubrail in the water). I never had any obnoxious vibration other than the exhaust tone.

Does this boat's rubrail set close to the water level?

No not any diff than any other 35 I’ve seen sitting in the water.

Well, then maybe look at what flat rate said about the deck to hull joint around the swim platform. The rub rail is easy to remove and reinstall around that area. What I've seen is the old sealer around this area drys out and you've possibly got some relative motion between the deck and hull resulting in a rattle? Typically this causes more of a water leak, rather than a rattle. But it's easy to check.

On a Fountain with molded in swim platform is not glassed around the swim platform itself, therefore they used sealer around this area - the rest of the boat is glassed together.

Since you are new to Fountain, there is quite a difference in sound at idle between a Fountain with a molded in swim platform and a (as an example) Baja with exhaust high above the water line. They do vibrate, but shouldn't rattle.

Good luck and let us know what you discover as the root cause.
Terry

Every one I have ever been on made that noise. We had a brand new 1999 triple 42 and it vibrated like hell when it was new.

Thanks All In.

infigured as much with 500s and headers it’s probably vibration. The boat has other issues. Both steering pins are shot and have a slow leak through the steering arm in the transom. Just deciding if it’s something I want to get into. I’m guessing it’ll need both Gimble rings replaced at a minimum. Rest of the boat is super clean interior wise. 55k for a 01 a lightning and 500efi @400 hours

I had a 92 35 that all the way across the back wasn’t sealed. If I backed it down a steep ramp water would flood in and both bilge pumps would be running going up the ramp.
Good luck with your purchase they Our fun boats

Passed on the boat. Got a diff 35 instead