I sure did. This was probably 1997 or so, I had a pickup with a superstar 121 I bought from a pawn shop, and I used a homemade 9’ copper antenna on a ball mount for DX when parked.
For the wire: I used a car radiator, and soldered a heavy copper wire to it. I bolted it to the frame of the truck and tossed the radiatior in the intercoastal waterway.
Honestly, if it made any difference, I couldn’t tell.
Just parking on a point where you’re nearly surrounded by the water made all the difference. On days where there is noticeable QRM showing on the S meter, it will often go up 2 s-units as you pull up to the shore.
With my 8 watt radio I had no problem talking DX on AM any time it was open, and generally speaking, could talk to absolutely anyone I heard. Would often get flack trying to tell people I was on a mobile. Some people even got nasty, and cussed at me.
Much the same today, when the band opened up this afternoon I could pretty well talk to any station I could hear, provided we could agree on a language (English). Just 35watts or so, Wilson 5000 magnet mount, and no problem working Brazil, Bonaire, Venezuela, and several islands I’ve never heard of. Once I pulled away and headed toward the house, no more dx. The difference today is the guys get a chuckle on SSB when I tell them I’m mobile.