I am stuck working in London at the moment and have decided to design and glass a semi gun for travel. Only problem is the longest board I have owned was 6’8” and I have no idea how to do a convex bottom / reverse V / V panel or V with concave etc… And there are no boards like this to look at here in LondonJ
The simplest design seems to be a V panel through the last third of the board, with the most V between your feet in front of the fins, so have tried to do that.
Could someone who knows a bit about semi guns take a look at the Aku Shaper file attached and tell me if I have made any serious mistakes so I don’t waist a lot of materials.
The FCS M7 or M5 glass flex fins will be set up using the McKee formula so that I can try both quad and thruster. I have talked someone into shaping the board using their Aku machine and will then sand and glass using least toxic epoxy with 6oz glass on the bottom and 2 x 6oz glass on the top. There are some very rough fin placements for the FCS plugs on the Aku shaper files at the moment.
Dimensions: 7’2" x 11 1/4 x 19 1/2 x 13 1/2 x 2 ¾
I have also done one a bit bigger 7’4" x 11 1/8 x 19 1/2 x 13 1/4 x 2 ¾ with the same bottom.
The V panel is 2.5mm at the highest point (second slice) and 0.5mm at the tail (first slice). The rest is flat.
2mm concave seems to be good so assume 2 or 3mm convex is similar?
Nose rocker: 6.50”
Tail rocker: 2.75”
This is my first board so go easy…
Height: 6’3”
Weight: 190lb
Waves: Planed trips to Morocco this winter and remote Indonesia in the summer. Average surfer 10+ years small waves.
Mc Kee fin formula 7’3” board
Board length 7’3”
Distance from tail Back fins 14.8 cm 5-13/16"
Distance from tail Front Fins 31.8 cm 12-1/2"
Thruster tail fin for M5 Multisystem 9.2 cm 3-5/8"
Width between back fins Width at 12" up from tail Under 15" 6-5/16"
Having lived in Hawaii all my life, there’s a few things that I can suggest for a semigun for waves larger and more powerful than those you usually ride.
Find a good gun board about the same size as what you are making and map out the rocker. If your rocker is dodgy, nothing else will matter. The board will suck. Flat to panel vee I would avoid. It is particularly useful to have a little roll in the nose entry. Makes the board much more sea-kind and catch waves more easily. The forward vee/roll is particularly suited to larger more powerful waves. One of the legendary shapers here does my gunnier boards with forward roll into a flat ahead of the fins and then nearly flat with just the slightest roll out the tail. These boards are quads, and a rolled bottom seems to work particularly well with quad setups. Just don’t let it get too peaky in the center. Boards that are flat in the nose can be really harsh in bump or at high speed. Or at least use a slight vee all the way through with a 3" or so blended flat down the stringer. Rusty used this bottom a lot through the 80’s on Occy’s boards for the North Shore. I’ve gotten to ride a couple of them and they went fricking insane in bigger waves. Just remember, the board has to plane no matter what, so keep the vee, roll, etc., to the minimum required to do the job. Subtle is best. Also I’ve found that boards with a lot of vee just ahead of the fins seldom work well for me. Personally, I think you’re better off with a flatter area between your feet to keep it lively. Of course this all depends on rockers, and everything else. Just be careful of adding too much contour, especially in that narrow tail. Good luck.
Ok, first I have ‘borrowed’ the rocker from a board for DOH waves. All credit goes to the shaper and not me. I was going for a more contemporary symmetrical rocker without the flipped nose, but I’ll try that next time.
The nose now has 0.5mm V/roll. At 1 foot from the nose there is 1.5mm V/roll. The middle has 2mm V/roll, the fins 1mm and tail 0.5mm. The stringer has been blended flat to 3” as suggested to avoid being “too peaky in the centre”.
I moved the wide point forward to the centre of the board and rounded the tail a tad.The rails probably need another few hours to get them perfectly curved.Now at 7’3 over curve and nose rocker is 6 5/8.
Thanks for the great comments, this might even be surfable
I’m on a tight budget so am going to use the newish FCS M5 or M7 glass flex which are reasonably cheap here. Someone is going to lend me the FCS drill bit.
As mentioned above will use the McKee formula ( http://www.mckeesurf.com/…ckee/multisystem.htm ) as a starting point with FCS plugs for quad and 2 extra plugs at the back to try it as a thruster.
I guess if you live in Hawaii it’s a pretty boring board, but if you don’t surf bigger waves that often it is kind of interesting.
Hi RDM, I would love to have a McCoy, the shape makes a lot of sense to me. I bet it catches waves really easily and is super fast at Gunnamatta, Express Point or Winkipope.
I spent the whole weekend looking at rockers. I found one 7’ Tuflite from a ‘little known’ Santa Barbara shaper in London, so have used that as a beginning template for the rocker. I spent about 20 hrs and ended up with a rocker that is very similar to the one Bill Barnfield added in the Convex Bottom Gun thread. I like the way he has put ‘vee into concave’ through the fins, I’ve read that Tokoro and other shapers do that. I’m going to give that a try also.
The Aku file above has been updated if anybody has any suggestions.
