Boss Up Quick Facts
Slater Designs Boss Up quick facts
| Brand / shaper | Slater Designs – Kelly Slater’s label, built by Firewire Surfboards in Carlsbad, California; designed by Dan Mann in partnership with Kelly Slater and Kevin Schulz |
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| Board type | Utility performance mid-length – the bigger brother of the S Boss and Kelly’s first-ever mid-length; the one-board travel quiver of the Slater Designs range |
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| Best waves | Everything from smaller surf to barrels: punchy open-face waves for carving and linking turns, and big points like Pavones or Rincon or even a big day at Sunset. Firewire charts it for 2–6 ft |
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| Skill level | All levels, beginner through pro |
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| Tail | Round tail |
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| Design | An elongated evolution of the S Boss with bigger dimensions and a longer rail line for drive; a shape that does not demand you dial in your volume perfectly – any surfer can ride it in a variety of sizes |
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| Fins | Five boxes. Firewire recommends the KS1 5-fin template configured as a quad (Kelly’s Endorfins KS1 upright pivot set; Futures single-tab or FCS II dual-tab). Dan Mann’s Manncave set is the raked alternative. Futures boxes on every board. |
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| Stock sizes | 6’6 to 7’6 (39.5 L to 51.1 L) |
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| Sizing | Firewire’s team recommendation: roughly 13 liters more volume than your standard shortboard |
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| Constructions we stock | Firewire builds the Boss Up in I-Bolic 2.0 (the 2025 range was I-Bolic and I-Bolic Volcanic). We have stocked it in I-Bolic and in I-Bolic with Volcanic basalt lamination |
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Boss Up Q&A
What size Boss Up should I get?
Firewire’s team recommendation is to ride roughly 13 liters more volume than your standard shortboard. A surfer on a 30-liter shortboard would look at the 6’10 (20 3/8” x 2 15/16”, 43.0 L) or 7’0 (44.3 L); a surfer on a 26-liter board would look at the 6’6 (39.5 L) or 6’8 (40.8 L). The chart continues 7’2 (46.4 L), 7’4 (48.4 L) and 7’6 (51.1 L). Firewire also notes the Boss Up does not demand perfect volume – any single surfer can ride it in a variety of sizes.
What fins does the Boss Up use?
Five Futures boxes. Firewire recommends pairing it with the KS1 5-fin template configured as a quad: Kelly Slater’s Endorfins KS1 is an upright set with incredible pivot (small, medium or large) in Futures-compatible single-tab and FCS II-compatible dual-tab versions. For more drawn-out, driving turns on a board this long, Dan Mann’s Manncave set – a balanced rake template – is the Firewire alternative; on other brands a raked quad or thruster set does the same job.
What waves is the Boss Up for?
It is the most versatile board in the Slater Designs range – it works in everything from smaller surf to barrels. The Firewire crew loves it in punchy surf with an open face for carving and linking turns, and while many look at it for small, gutless days, Firewire says it would work well at a big point break like Pavones or Rincon, or even a big day at Sunset.
How is the Boss Up different from the S Boss?
The Boss Up is an elongated evolution of the S Boss with bigger dimensions and a longer rail line for enhanced drive and versatility across all conditions. The S Boss runs 5’4–6’4 as a universal shortboard; the Boss Up runs 6’6–7’6 and is Kelly’s first-ever mid-length, crafted to cruise across weak faces and grind through cavernous overhead tubes.
Who is the Boss Up for?
Any surfer who wants one board for everything – Firewire calls it the board you would travel with if you could only bring one. It is rated for all skill levels and forgiving on sizing, so it suits mid-length first-timers as well as experienced surfers who want maximum performance in a purely versatile package.
What construction does the Boss Up come in?
Firewire builds the Boss Up in I-Bolic 2.0 – an I-beam core with flex controlled at the rails by high-density foam, plus a fully engineered carbon strip inlay on the bottom for extra strength. The 2025 range came in I-Bolic and I-Bolic with Volcanic basalt lamination, and we have stocked both. Each board on this page lists its construction and fin boxes.
Can I custom order a Boss Up?
Firewire builds the Boss Up in set stock sizes rather than true one-off customs, so there is no custom board builder for it. If the size or construction you want is not on this page, we can usually special order it for you from Firewire’s current range – contact the shop and we will check availability and lead time.
