Buy a 6 inch random orbital. The best there is is the porter cable, it's just a great unit. But, that being said, the 6 inch rigid is pretty good and good value for
money. Likely they're all pretty good these days.
If you are doing
bottom paint, or any sanding really you should do the following :
-purchase a rigid vac and an extra hose. Connect this up to the random orbital, you can use it on any unit. Have some duct tape, tape the connections if needed, really not hard. Empty regularly into the one bag....you will be amazed how much you collect!
-purchase a respirator.Does not have to be full face. Don't bother with the paper masks, total waste of time. Paper masks are for idiots.
By spending an extra hundred bucks maybe on those two items you will get years of use and stop pretty much all dust, not just dust into your lungs, but dust in general, dust on your
deck, in your
boat etc.
The respirator is overkill but worth it. I was using that setup once indoors and while sanding was thinking what percentage of dust actually got picked up....midway through that thought a mosquito flew near the random orbital......and got sucked into it. Question answered.
oh, another trick I use is putting a
single layer of paper towel over the respirator filter.....basically a pre filter. Stops a huge amount of dust even getting to the respirator filter and makes the filters last way longer.
Last point. If you have a big buildup of
bottom paint, you can blast 90% off with a 5 inch grinder, Set up a container on the vac hose, cut out one side and hold it with the grinder, once again you can collect an easy 80% of the dust this way and save a huge amount of time on the sander.
Just my opinion, offend as it may (yes, paper filter users)