Swivel rod holder

[mrfishy]

Would one of those plastic gimble swivels work

[Glenn W]

Would one of those plastic gimble swivels work

Sure, for about 1/100000000 of a second. I've used a non swivel holder on several boats. Sure it works, but as Gerry said, not as well. I have not tried the improvt ball, but consider there would be no gimble to lock the rod and the rod butt would be sitting only on the crown of the ball. Also, remember you can adjust the tension on the swivel base.
In short, sure you can get by will a regular (fixed) holder, but for $125 you get a much more effective and safer tool.
BTW, the swivel holder really shines in wrestling with a dredge on a sporty day.

[Water Damage]

you can get a drop in swivel base adapter from So-Lo marine. Some of the catalogs carry them but you can buy direct from them also. I called the guy before I bought and he told me it is the same mechanism they use on their heavier rod holders, just made to be a drop in. I bought a couple of them and they have worked great for us for over a year now. Took them out and inspected them not too long ago and they looked good as new.

I agree, the plastic ones are junk - but these are pretty nice. Been thru a lot of hours under pressure form the planer rod and a bunch of fish - no problems yet.