I've got a 460 Ford with about 20 hours on it, the left breather there's a fine oil Mist coming out of it not all of the time and making a mess of my boat is there anything I can do to get rid of that mist I've got a PCV valve on it but it doesn't seem to be helping

When does it mist? WOT, cruise,  idle?

GT

First off, you need to find out why you have so much oil mist or blow by/crank case pressure. Regardless of how many hours you say are on the engine, I’d start with pulling the spark plugs, give them a visual and then perform a cylinder leak down test, this will tell you a lot about how well the cylinders are sealing between rings and valves, and even head gaskets. One thing you never want to do is just mask or Band-Aid a problem, it has to be corrected, mechanical problems just don’t go away, they get worse and sometimes cost you more in the long run.

This could be a possibility, without pictures of the set up it’s hard to tell. Style of valve covers, baffles inside or if the breather is located towards the rear, allowing oil to get up into the breather easier. I like sealed valve covers on a boat that both covers are vented into a sealed collection canister that is vented, like something from Moroso. I still would diagnose the cylinder health for piece of mind just to make sure nothing fishy is going on causing excessive blow by.

When you come back after a hard run, does it "puff" a little breather smoke out if the breather?

I with the above, leak down,  compression test to to have that knowledge.

Honestly,  the PCV is pretty useless on a jet boat.

That being said,  what weight oil,  capacity of the pan and how much oil,  how many rpms does it run?

Has it always done this?

I would go to two MOPAR style breathers and route them to the scoop/flame arrestor,  whatever.

There is more information needed on your part to be able to make a determination on how to solve it.  We know the symptom,  all we need now is a potential cause.

GT

Not yet. The boat is at the river I'm going to check compression,  and valve cover baffles, etc.. going out this weekend. I like the catch can idea. And no it doesn't  smoke after hard run.