Fine-tuning dimensions and fin placement for a 9' 1 " semi-gun

General Discussion
1

Hi all

I will be replacing a tri-fin semi-gun (9’ 0" x 20 3/4" wide x 10 1/2" nose x 11" tail x 2 3/4" thick). I have ridden it for three years, had a lot of fun, but structurally it is wearing out. 

I am coordinating with a local shaper to build a replacement, that is thicker and has a heavier glassing schedule. We will be using a US Blank 9’2"A. The shaper suggests we increase the length one inch to 9 ’ 1" to take advantage of the rocker that is already built into the blank.
Given that rocker is one of the crucial ingredients, the idea of increasing the length by 1" to minimize the risk of messing up the rocker sounds good. And I wouldn’t mind an extra inch of paddling power.

Basically I want the same board as before except for two big changes:

 1/2" to 5/8" inch thicker to be able to catch more waves in San Diego reef breaks that are often crowded with mailbu-style long boards (i.e. 9’ 6  " x 22" x 3"). Also longer term I intend to travel with this board and the extra volume may increase the board’s performance envelope for bigger waves.
 
A heavier glass job (3 x 6 oz on the deck with 2 x 6 oz on the bottom). I am going heavier mostly to increase the durability and lifespan of the board. However I rode a gun last year overseas (9’ 2" x 19 3/4" x 3 1/4") with the same glassing schedule in double-overhead conditions and noticed that the increased weight and momentum were useful for penetrating chop on the takeoff.

I have spent lots of time going through the Swaylocks Forum, to educate myself as much as possible, but I still have some unanswered questions.

My Questions are as follows:

  1. Should I increase the width of the board by maybe 1/8" or 3/16" to keep the plan shape as curvy as it is now? I like the fact that this particular semi-gun is curvier and looser and fun in head-high surf. I already have a couple of of 9 foot guns with more parallel outlines for bigger conditions. Will the outline lose curve if I don’t tweak the width up proportional to the one-inch increase in length?

  2. Should I move the side fins forward, say 1/4" or 1/8", to help keep them closer to my back foot? Or should I leave them at 14" from the tail where they are now? The side fins on my old 9’ 0" semigun were at 13". About three months ago I had them ground off and reset one inch farther forward at 14" from the tail. The difference was dramatic - smoother, tighter turning radius, a bit of controlled tail slide,  less awkward body positions on cutbacks. I didn’t seem to lose much in drive or projection either. I left the trailer fin where it was at 4 1/8" from the tail.  The old fins are almost identical in outline to Future Fins “Pancho Sullivan” model (Height 4.76", Base 4.56", Area 17.51"), so I will be using Future Fins Pancho Sullivan model on the new board.

  3. Now the big question? How thick can I go without compromising the rail foil and flow of water over the rails when the board is on-edge?  I would like to use as much dome in the deck as possible to maintain volume, but still have fine, thin rails as much as possible. The rail profiles on the board I am replacing are pretty typical: 50-50 rounded entry at the nose transitioning to tucked-under edge, transitioning to downrailed hard-edge at the tail. For what it is worth, last year I rode a 7’6" x 19" x semi-gun for a couple of months that had a flat deck and much fatter rails than my 9’ 0" semi-gun, even both boards were 2 3/4" thick. Fat rails did not suit my style of surfing - which is basically to use a thinner rail to position high on the face and set up big carving cutbacks. As I mentioned earlier I would like to go at least 3 1/4" thick, hopefully 3 3/8" thick or maybe even 3 1/2" thick? The basic idea of this board is to have the paddling power to deal with crowded conditions on San Diego reefs by getting into the wave earlier, plus the ability to go steeper and deeper on the drop than a mal would allow. Also I intend to travel with this board and use it in bigger conditions elsewhere later. I saw a 5" thick board in the Swaylock’s “How thick is too thick” discussion that looked way thinner than it was, so I can see it’s possible to dome the deck to maintain thickness and volume and still transition to relatively fine rails.

  4. At the wide point, how far in from the rails should does the thinness need to extend for sensitivity and ability to carve?  In other words, at what point do we need to transition from maintaining volume to achieving good rail foil?

  5. Would it be worthwhile to use a 6 oz deck patch rather than a full third layer of 6 ounce cloth on the deck, to reduce the swing weight of the nose?

About me: I’m 5’10 tall x 152 lbs x size 8 1/2 feet.

thanks in advance

 

 

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http://www.swaylocks.com/resources/detail_page.cgi?ID=2282

3

Thanks Robin

That’s a beautiful board. A great blend of gun and curviness, that no doubt is the product of lots of experience in heavy conditions. I don’t have a photo of the outline or foil of the 9’0" board I am trying to reproduce and improve because I don’t have access to a digital camera at the moment. The local shaper and I traced and cut a template off my old 9’0" semigun board and we were planning to use that as a starting point. But after looking at the outline of your (9’ 7" x 12 1/4" x 22 1/2" x 12 3/4" x 3 1/4") I am tempted to rethink the whole project and use something like your outline. The extra width would add paddling capability. Your board looks curvy and manueverable which is what i am looking for in this addition to my quiver. The blank should arrive in a couple of weeks, so I have time to think it over.

 

By the way, I checked out your Hanalei Spear designs too. Awesome.

4

man… I’m 190 lbs, and I can’t imagine needing a gun that’s more than 3" thick… ever.  Forget the domed deck and carry some of the foam out to the rails.  Believe me, if you go from 2-3/4" to 3" you’ll notice the difference.  Boxier rails doesn’t mean you can’t carve turns.  That’s a function of all of the parts.  Look closely at a Brewer gun.  They are the gold standard.  

I don’t think of San Diego as somewhere with extreme surf, where you need a serious gun.  It sounds like you’re looking for a gunny performance longboard.  Semi-gun usually means shorter than a full gun - what I think of as 9’ or longer.  What you said about the malibu style longboards backs that up.  If you need a gun for REALLY serous waves, you’ll want something specific to that spot.  

Since you’re in Sand Diego, head up to Oceanside and check out some Brewers at Linden’s shop.  While you’re there, have a chat with Gary.  He’s someone else that knows guns.  Gary recently paddled in to the biggest wave at the Nelscott Reef contest in Oregon… at nearly 60.  Peter Mel made sure to mention that at the Mavericks opening ceremony - where Gary is the head judge - last Friday.  

5

OK. Thanks for the input. One of my worries is going too thick and ending up with a dog. You are right that the board is overkill for San Diego. But I have two quivers, one in San Diego, and the other in my house in Chile. My Chilean gun is a 9’2" x 19 3/4" x 3 1/4" shaped by Pedro Salerno for Punta de Lobos with a 2 + 1 fin setup. I like it. Unfortunately I spend most of my time in California working, so I want something for SoCal with more or less the same volume, wieght and thickness for my SoCal long board, so that I can transition to my Chilean Gun easily, and have confidence when I spin and go.

Both places have their challenges - in SoCal it’s the crowds, in Chile it’s cold water, currents and raw power. I talked to Gary Linden at the Surf Expo in Del Mar last month. If and when I do take the next step up size-wise, he would be logical choice to shape it for me. Gary’s recommendation for me for Chile was 10’0" x 3 5/8" thick (minimum).

I have managed to get two identical 6’ 9" x 18/ 7/8"  Al Merrick k-stepup board positioned in Both San Diego and Chile. For me it’s a real luxury and confidence builder having the same board in both places. I want to do something similar with the 9’1" as the gringo brother of the 9’2".

Anyway. Thanks for your input. it is greatly appreciated. I want to get as many opinions on this as possible. The more I think about it I should be going a bit thicker on the rails. During the SoCal swells in late October I buried the rail so deep on a couple of turns that when the wave backed off a bit i couldn’t get the rail back out. I would imagine a bit thicker of rail would have helped. I’m still just learning.