: I'm within a few days of starting to sand my guillemot and thought it would
: be helpful to get a few of your opinions.
: I currently have a 5" ROM with the velcro and it likes to throw the
: sanding disks around the shop. I also have a friend who offered to let me
: borrow his hand held belt sander, & I have built a few half sheet
: sized faring boards.
: I also just happen to have a little birthday money that could go toward a
: half sheet ROM if it is worth the expense. I'm a little nervous about the
: belt sanders ability to turn a nice boat into sawdust and figured that the
: ROM would be a little wiser but I really don't mind taking the time to
: hand sand with the faring boards if it will give be a better finished
: product. I would love to hear your comments and advice.

: I also couldn't help but include a photo, I've got a bad case of the proud
: new papa syndrome that comes with building the first boat.

I once counted in my head the number of sanders I have. It's gotta be under 50. The ones I use the most are my Bosch 4.5 AND 6" ROM with the hooks. Problem is it's hard to get real course paper(under 60 grit) for them. I came across some 40 grit for the 6" at a Builder's Square that was going under and bought it all.
Unless you're knocking down some real high wood the ROMs will do to about 100 grit. Then you'll want to go to your long boards.
Another sander I like is an air powered body file. This uses a 3 by 18" sheet and is used in auto body work. If you use this tool first you'll save a lot of time and have a pretty fair hull. It's agressive but easier to control and produces a better result than a belt machine. If you've got air, this sander runs from fifty bucks up. I picked up an old Chicago/Pneumatic that needed a new valve seal at a used tool shop for ten bucks. It's ten times the tool as the Chinese version it replaced (where'd you think I got that valve seal from?).
I have used this tool to long board by removing the standard shoe and replacing it with a homemade shoe that uses a full sheet cut in half and glued up end to end.
I have used a belt sander, but only to clean up a sloppy epoxy/glass job on a exterior plywood skiff. Nothing like it to knock down big globs and pools of cured epoxy. I wouldn't go near your work with it. And you're going to be just as artful with your sheathing work as you have been up to now. Right?
As for quarter sheet machines, it's hard to beat the old style Porter Cable that sort of looks like a chess pawn. But this is really a finishing sander. I keep two around so I can have 150 and 220 grits available for my final work. This way you don't have change paper as you move from section to section.
Lastly, remember sanding sucks, it's really no fun, but your final product will reflect the effort you put into your sanding. Sanders of any type speed this work a hundredfold making the whole project more pleasurable, which is why we're here. Right?