Shaping a V Bottom with a Flat Tail.


I’m shaping some Mini Simmons and wish to put a slight V in the bottom. In reading these previous threads:

I see that putting the V all the way through to the tail is not advisable for a Mini Simmons as it may slow the board and make it track more. The advice is to finish off the tail with a flat bottom.

My question is what is the best way to do this? I can see that the key is getting the relationship between stringer and rail rocker correct. The V requires a cut in the rail rocker but if that is followed with a flat bottom to the tail it will require the stringer to be cut down to keep the transition smooth. As this would cause the tail rocker to increase, which is something I wish to avoid with the Mini Simmons, I am at a dead end in trying to think of a way to do this.

Any advice?.

in your meditation 

while the ubniverse is

pure silent void

ask: what would joe baugess…



all will be right with the world

when it is a real MS.

right Joe?

Panel vee in front of fins, to flat out tail.   Could show but hard to explain. 


On wide tailed boards i like a vee in the tail...personal preference.  I usually vee from in fron of fins to out the tail. This keeps the stringer line flat, but vee helps board go from rail to rail.  The draw back is when the wave flattens out, the board bogs, but if wave stays lively, so does board.

I agree with resinhead, I like a bit of vee on super wide tailed boards, especially simmons’. Everything you do in shaping is a compromise. For instance, more vee = more maneuvarability and less vee = more planing/speed, and you can’t have both! If you have to go flat out of the tail then make sure you blend it properly. The vee on the simmons isn’t too drastic so it shouldn’t be any problem blending that into a flat tail. Most guys start with a very flat blank. I like to use the US Blanks 6’2"A if I’m making a 5’6", and I’ll drop the tail rocker by -1/4" from center. This will help you to avoid cutting in more rocker than you want to. Cool?


Thanks for your comments guys. I’m humbled that my question attracted such illustrious company. Sort of the Swaylock’s First Team…

I see that the wide tail will allow a small amount of V at the end without effecting speed too much. I’ll start the V about 12 inches forward of the fins, just where the back foot would be placed. Max depth of 3/8 inch about 8 inches behind this and rising gradually to a shallow 1/8 inch V at the end of the board. I’ll also cut 1/4 inch from the tail rocker from center to keep my tail rocker lower. I’ll just take my time and do it by hand with the sandblock so that I can see the shape as it is formed.

Envisioning this V shaping is interesting. Got me through a very boring meeting today… I keep thinking about the rails. How much of the maneuverability afforded by the V is from the bottom shape and how much from the added flip in rail rocker? How to keep the rails smoothly flowing with a V added? And, is there a way to keep the rail rocker independent of the bottom shape?

Maybe you could have a short section of flat bottom coming in from the rail for say 4 inches. Then a cut into the bottom at a sharp angle equal to the depth of your V. Then a straight line cut from the bottom of this sharp angle cut up to the stringer. A cross section would look a bit like a stretched “M” with the two side flats on either end. That would give you the V panel in the bottom without touching the thickness or rocker of the rails.

Or not. I’m certainly overthinking this. Plus the glassing would be tricky to say the least.

Well, as I learned in Marriage 101, it’s all a compromise. Thanks again guys.


Maybe not, but you can have neither!

good luck.


These guys are Swaylocks first team; I’m sweeping under the bleachers after the game.

You need to build a v shape from the bottom of the rail to the stringer.  If you put flats next to the rail you’ll end up with a spine instead of a nice roll or v.  Instead of making the board easy to roll from rail to rail you’ll have a board the wants to track more than roll.

If you put the bottom contours in before you cut your deck rail bands, you can adjust the rail and tail thickness from the top.

I’ve watched a few guys cut v’s with power planers and I bow to their skills.  I’ve seen them cut like rail bands and I’ve seen them cut from stringer to rail (that version is just plain nuts).  A disk sander with a hard pad seems best to me but I drink too much coffee… I do mine by hand using a hand plane and sanding blocks.  Here’s how I do it.

Start with a roughed, blocked shape. Outline cut out and trued. The tail rocker should be a little flatter than you want the final version to be by 1/4 to 1/8" (more if you are really planning on a deep v).

If you look at the board from the side, you’ll see that the rail rocker is exactly the same as the stringer rocker.  If they are not you have a twist in the blank or didn’t block it correctly.  Fix it now or you will be sorry later.  Keep the blank with the bottom up for some measuring…

Take a pencil and mark a dot on the outline cut right where it meets the bottom where you want the v to start.  Then put another dot where you want to to have the maximum depth of v. Measure down from where the bottom and outline meet and put that dot at the maximum depth of v you want to cut.  Then you put one last mark where the v should end. 

Those three dots now mark the rail rocker. You can add some more dots or take a batten and connect them up into a smooth curve.  This will give you a guide to cutting the v and help keep your rail rocker nice and smooth.

Do the same dot thing on the other side. Try to keep everything as squared up as you can to keep it all symetrical (unless you’re an asymetrical guy…not that there’s anything wrong with that!)

I start cutting a 45 degree cut where the bottom and the outline meet, like a mini rail band. Make sure it all flows smoothly, feathering in from the front of the board and feathering back out at the tail.  Just keep knawing away until you get to the stringer.

When you’re done, you should find a funky spot where the v ends at the tail.  That is where you’ll add that 1/4 to 1/8" kick to the rocker to smooth it away.

I always refered to this kind of v as “dome” v.  You can make the v panels flat for a crispy feeling or round for a smooth feeling.  

Good luck!

Wow! I guess I forgot that I wrote all this same crap before! My wife says it’s the second thing that goes…

Thanks Lee, that helps a lot. Your wife's memory is good,

let's just hope she's wrong about the other stuff.

As my spatial imagery skills are like blobs in a lava lamp... one second I see it, the next second it's gone... I focused on what I found to be the easiest concept to visualize - the rails. Which is what you guys are telling us is the way to go. After reading your post the lightbulb started to glow.

I should have added this information to my original post, however on this type of Mini Simmons the rail rocker line has a lot of movement, From a soft displacement rail in the nose to a more 50/50 rail in the center, to a 60/40 behind center and finally to a hard down rail at the tail end. It seems that the angle of the rail rocker to the bottom line as it approaches the tail is the opportunity to keep the V-to-Flat bottom transition smooth.

This is due to the fact that in forming the down rail, the rail rocker line closes with the bottom line as it approaches the tail. So if we use the rail rocker line in this area as our guide for the V blending, it will naturally pull the V into a flat as the rocker forms the hard down rail. As you describe it, where the rocker rail line to bottom line distance is say 3/8" (for a max cut depth of 3/8"), this should be the point at which your transition to the flat tail should start. The full-depth body of the V at 3/8" can be continued forward of this point as far as you wish to have the V. Forward of that you can gradually raise the V and blend it back into the flat section of the bottom forward of the V.

As you say, some of the stringer at the tail will have to be cut down slightly. But a lot of this will be mitigated by the rocker rail and bottom line blending together in this section.

Maybe.... Let me know where the holes in my thinking are. Thanks again.



 more vee = more maneuvarability and less vee = more planing/speed, and you can't have both!



Maybe not, but you can have neither!

good luck.


These guys are Swaylocks first team; I'm sweeping under the bleachers after the game.


we might not wear helmets, and ride to the game on the short bus. Small fish in a small pool etc,etc... But I don't see you offering up any insights. It pretty easy to just come to this place and take information, then talk trash from 50,000 ft.  Why don't you give the guy an explanation on how you'd do it?  Maybe we can all learn something? I never claim to be an expert, I just let my work do the trash talk.

So in short, why don't you show up to the game here and buckle up. Come join us on the short bus or go put your dress on Alice.


what you described is what Diff called his roller bearing V, before thinning the tail, shape in the v running out the end of the tail, then rocker and flatten from in front of the fins to out the tail

Yeah, Like Jim said.
When I started building boards I found a description of “typical” performance boards for Hawaii in the 70’s that stuck in my head. I don’t know if it was Brewer or another of the heavies at the time. But they described the bottom like this; a bit of rolled vee in the nose to keep it free, going into a football shaped flat spot thru mid board and under front foot, a mild vee in the fin area into a flat uplifted tail".
I try to figure foiling and bottom/rocker adjustments at the same time. Rails don’t get put in until all that is set, otherwise they get distorted. I look at what I have to do with rocker first and foil as a part of that. They go hand in hand. Get in the neighborhood of my desired foil cutting from the bottom (poly blank) adjusting rocker as needed. Then install my vee and concaves. Then finish foiling if needed on the deck side usually just a bit of thinning in nose and tail.
All that is mostly regular boards, a mini Simmons is a bit different.

Wow! Sure! Maybe! I got lost…  Anyway, at this point don’t worry about the rail shape.  You’ll see.  Square it up, put in the v, adjust the stringer rocker to blend.  Now you’ll have a blank canvas on which to put the rail shapes.  It’ll sort itself out.  It’s a miracle…

Remember that rocker is the single most important factor in how a board will turn and trim.  V’s and concaves just accentuate the effects of the rocker.  The rail shape is pretty much fine tuning everything so, on its own, the rails don’t affect things as much as the others.  In other words, you can fuck up the rails and you won’t notice it as much as a poorly executed rocker or bottom contour… 

Ok, thanks Lee. That makes sense. I'll focus on the stringer rocker as it is the baseline of all the other design. Besides, I can visualize the stringer line a lot easier than the triple combinations of stringer, rail, and bottom configurations all moving around... Makes my head hurt just writing that...

I'll work one area at a time and keep it simple. I think the fun is coming back...