Dimensions: 5’9” x 21 1/4” x 2 5/8” and 5’7” x 21 1/4” x 2 9/16”
Year Built: 2020 and 2022
Shaper: Woody Moore-Surfboards By Roy
Manufacturer: Moonlight Glassing and Gordon & Smith
Model Name: The Rat King & The Urchin Board
Location: San Diego
Description: Stand Up interpretations of 70’s single fin fish kneeboards (somewhat obscure permutation of the twin designs). Been refining these since 2018 every so often in the hobby bay. I am pleased with the smooth ride, big leans, and ability to hold in steeper faces. Slower in the take off than the keels fish, the boards hold and drive are addictive though. I’ve even built 60’s surfskate style skateboards to capture that beautiful lean and grind of the water ride.
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nice board, I have ridden a swalllow single before. it went well.
Nice. I’ve always wondered how a single-fin fish would perform.
If you like that hard lean feel and have a decent grade, you should try one of these
That’s precisely how it goes. A lean just like that. Of course, I shape belly in the nose, a pinched 70/30 rail to engage the wave face, and then use an upright high aspect, reasonably flexible fin to transition rail to rail. It is not a hull or even a modified hull. However, some hull characteristics are employed with good success.
I have evolved presently to surfing mostly swallow tails myself. However, I emphasize that this tail block is actually greater than 11” pin to pin. That puts it into archetype fish country-which was the foundation for my interpretations.
Sounds like a really interesting design. You describe the nose, what do you have going through the belly and tail of the board? The photo’s look like concave but that might be the tail shape skewing the perspective.
Hi, after belly in the nose, the bottom contours on both of these boards are similar. They feature a gentle single concave that transitions to spiral vee out of the tail. Some have had a flat bottom to a spiral vee out of the tail. The vee is about 1/32-1/16” and seems to help the rail to rail transitions. The rail line is pinched but below 50/50. 65/35-70/30. Hard edge from 18” to tail. The wing on the Urchin board lines up with the typical trailing edge pos of the single fin for me- the theory being to create uniform disruption points for water flow around the board.
The board prefers an upright fin, but with some twang! I’ve had good success with about 8 1/2” fins. A friend, with more shortboard hop in his style, prefers a shorter, but wider base fin.
Oh wow thanks for the detailed description! I’m planning a 7ft single fin at the moment, your design has me intrigued. I wonder if it would translate well to a midlength? I’m riding a 7’6" that has belly the full length with 50/50 heavily pinched rails and a really broad (16" at 12" from the tail) tail. I was thinking of basing the 7’board on that as it goes really well in a variety of conditions around home (Hawkes Bay, NZ) but your boards look really interesting! Good food for thought, thanks for sharing.
I’ve built one to 6’8” personally. However, as the board gets longer, I narrow the tail block to a more standard 7.5-8.5”. You should look at examples of the Gordon & Smith summer fish from here in SanDiego- it’s an archetype for single fin fishes-although the tail block is narrower. It might work with the wide tail block on the bigger board, but I’m skeptical of the single fin hold when the rider is mid- board. I’ve always sought a “silver surfer, magic carpet ride” on the wave. Kneeboarding captures that sense the best in my opinion. I’ve tried to keep that kneeboard feel while I standup. This means that I keep the board lengths in the kneeboard realm of low to mid 5 foot range +/- 3-4 inches. In fact, my boards are pretty good on knees but they are stand up first. Yes, this has been already visited by the some of the greatest names in surfing. However, that’s the beauty of creativity. It’s always refreshing itself.
Two more shots: The Urchin is the top board with the single wing. The second photo is the “Rat King” with a personally modified L-Flex 8.5 fin. The mods increased the flex of the fin and reduced its drag for the small platform.
Thanks for the heads up, I’ll check out some of the G&S boards. Maybe I’ll stick with plan A on the mid-length and build something like your boards in a smaller format?
Wow, thats a beautiful board…I like the belly in the nose…I think it helps keep it above the water instead of digging into the wave on a little steeper drop ins.
Question, how did you determine where the bump location is placed. Some of Aipas are about 6 inches in front of the fin.
Hi,
Thanks for the kind words. Yeah, Aipa sting boards run that wing at typically 20-24” from the tail depending on the length of the entire board-which as you astutely noted is about 6” inches in front of the leading edge of a 10.5” fin box set on avg 6” from the tail block.
A wing is a powerful tool, in short, to create hydrodynamic release by disrupting the laminar flow of water along the rail of the board. Consequently you get a point of intense pivot to help turn the board. You turn quicker.
I try to coordinate the wing with the water release of the trailing edge of the fin design of the board. The idea is to have these two powerful forces working together to magnify turns and release. All releasing water at the general same realm at the same moment in the tail of the board. This is not the only way to use wings but a generally very sound theory to get the best from them. The Aipa Sting doesn’t employ a wing in this way but it does demonstrate successfully that wings can be used for dramatic effect in alternate positions.
The idea is to place the wing near the trailing edge of the likely position of the fin. On the Urchin, the wing is at 8” from the tail block. This is because I most often find that the trailing edge of my fin is somewhere between 8”-81/2” from the block-depending on fin size and rake. It’s different on a single wing keel fins
fish. Closer to tail.
As with any choice in board design, there are costs with benefits. Similar to deep concaves, Wings remove foam from the board. Depending on how far up the wing is, it could be substantial. This decreases the overall potential for the board. I use them judiciously and only if I think I can mitigate the performance cost elsewhere on the board.
Hope this helps!
Here is an example of single wing keel fin fish that I shaped recently. This template features a slightly smaller and more rearward wing to work in concert with the keel fins.
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