1. [See Video, Step 3A] Set the front fins with pencil dots (about 1/8 inch deep). This will help you envision where the back foot sweet spot will be when you fine-tune the vee or tail kick. Measure where the fins are placed on a similar finished board. Use your T-square to place pencil dots at the front and back of the fins (following the below guide for side-fin placement).

2. True up the stringer with a hand block plane. Since the foam gives way much easier than wood, having a nice flowing arc to the stringer will help act as a pattern when you use the sanding block to make the bottom uniform.

3. Blend or accentuate your vee and/or tail rocker with a Surform; or use the sanding block with 40-grit sandpaper. If used properly, the Surform can even out all the bumps and ridges. Hold it at each end and pull it back toward you at a 45-degree angle to the stringer. You can also push it straight ahead (with the Surform parallel to the stringer) like a block plane to blend or to clean up rail edges. A somewhat light touch works best with this tool -- never scrub in one spot since the Surform doesn't respond to brute force. Use it over larger areas with the same touch you would use if you were trying to level thick frosting on a delicate cake.

4. [See Video, Step 3B] Clean up/smooth out the stringer near the tail, if necessary, and switch to the sanding block with 40-grit paper. Use it to fine-shape and blend the flats and contours of the bottom together. Don't scrub in one spot. Instead, glide the block over one side of the board, using medium pressure and with a sort of fencing motion. Work from the opposite side of the lengthwise half you are sanding. This way the sidelights let you see what you are doing more clearly. The white edge of the rail will be defined in contrast to the darker walls. Use the stringer to support a corner of the sanding block so the wood acts as a guide as you move from end to end.

When sanding in the vee area, take care not to exaggerate it. Most novice shapers either end up with a big mound or no vee at all. For most modern board shapes, it would be better to have too little vee rather than too much.

5. After you've cleaned up the bottom to suit your eye (Settle out of court at the soonest opportunity. Don't be tempted to keep evening the table legs or pretty soon your board will be 1 1/2 inches thick.), it's time to cut in the bottom rail bevel. This will serve to form the rounded radius on the bottom side of the finished rail.

Most shapers do this last, but I shape it in first because it helps you plan out and control your rail shape and volume better.

Use the Surform to do this. Work from nose to fins, or fins to nose -- whatever you are most comfortable with. The bevel should feather out and disappear just in front of the forward fin settings.

The width and depth of this cut can vary and depends on the thickness of the board and what type of rail you want. For thinner boards or lower, tapered rails, the band you cut should extend down from the bottom edge to about 3/8 to 1/2 inches up. The typical medium-full rail on an average-thickness board will range from 1/2 to 5/8 inches, and thicker boards or those with soft, round rails can start at around 3/4 inches.

Get some measurements from other boards to give you an average to proceed on. Use your T-square to mark the amount of radius that you want (measured and marked on the rail at the thickest point of the blank), and you can use the pencil mark to guide you as you cut in this small band with the Surform.

Once again, a lighter touch with the Surform works best. Placing a forefinger inside the tool and using it to set the bite seems to help you keep track of where it is cutting and will give you more control.

It's funny that while the bottom shape of the surfboard is fundamental to its performance -- it's in constant contact with the wave face -- you really don't spend all that much shaping time dealing with it. Almost all the real labor comes later and involves the deck and rails because the bottom is relatively flat. Most of the compound curves meld together topside of the rails, so you spend a big slice of time blending the top of the rails into the deck in as seamless a manner as possible -- even though this really demonstrates the shaper's craftsmanship more than it affects performance.

Surfboard bottom shapes can be boiled down into two very simple components. Flats or straights are your accelerators. Any curves or roll (including vee) are control features; they help you turn the board more easily, but they slow it down in doing so. How all these components are grafted together is the foundation of the (seemingly contradictory) fast-but-loose surfboard we all want.

The control elements that fall under the influence of the back foot are the most important, as they affect turning capabilities. The vee panels, tail rocker, thickness taper (foil) and fin settings need to mesh together directly underfoot. This forms the sweet spot that you always hear surfers yakking about.

Once again, the best way -- for short-term understanding -- to get a handle on this complicated area of design is to spend some time studying or measuring a few similar surfboards from established shapers.

For long-term education, I think the best way to gain detailed knowledge about surfboard design is to ride as many types and sizes of any boards that you can get your hands on. Try and figure out which features are the ones that either let it rip or make it suck.

It is also great if you have an experienced board-builder around to mentor you, but I believe the first-hand trial of different boards in the design spectrum is far more important.