What effect would these changes make?

[Uncle Grumpy]

Sure, just keep it all the way up front, it's the back inside corner that does all the real surfing.

[rodndtube]

I use a nominal amount of rocker in my boards -- not much because the forward part of the board is also a planning surface. Rail shape is also important in the nose so that the nose automatically wants to slice out for an easier recovery when some pearling occurs.

[spudnut]

Does rail come into play very much when we are talking a 1/2" thick board? I just square them off mostly because I have no woodworking tools nor do I know how to use them. Also square rails are fast to make!

[Uncle Grumpy]

With a board that thin, square rails are fine. In fact better then fine, perfect.
Just don't get a splinter.

[rodndtube]

Square or rounded square should be best because they are already so thin. Any sharper will cause non-recoverable pearls and make turning hard.

[spudnut]

I don't know why this board keeps splintering, but it is the closest thing to my ultimate board yet. A day does not go by where at least one person comments about how fast it goes or just what is it and it looks like I am having a blast.

[Uncle Grumpy]

I don't know why this board keeps splintering,

I noticed in the OP you said it was marine ply.
Most of the readily available marine ply is domestic or Canadian stuff made with Douglas Fir which is highly prone to splintering (and checking on the faces).
It's often glassed in final use.

[spudnut]

Interesting! The Home Depot stuff was furniture grade birch. It is too flexy for my likes. This stuff is much more stiff, but still absorbs the bump. If memory serves me right, it is Douglas Fir. Is that a bad wood choice for a paipo?

[Uncle Grumpy]

Lots of the old plank boards were a combination of Redwood and Doug Fir and/or White Pine.
The Doug Fir was almost always used as stringers so there was no worries about splinters on the rails.
It's often used in boat building due to it's good strength to weight ratio and it's fairly high rot resistance.
The main problem with Doug Fir is the fact it can be difficult to sand and it's tendency to split and splinter.

So as far as building paipo with Doug Fir lumber or plywood, It's better then some but not as good as many.

Here's some info on boatbuilding lumbers and plywoods that are suitable for our purposes..
http://www.glen-l.com/wood-plywood/bb-c ... l#softwood
http://www.glen-l.com/wood-plywood/marine-plywood.html
http://www.glen-l.com/wood-plywood/okoume.html

[spudnut]

UG,

Thanks for the links. I just need to make sure I always keep some sandpaper around with this board.

[Uncle Grumpy]

FWIW, you might try a coat of epoxy followed by a few coats of paint.
That'll help keep the splinterage down.