The New Harley Ingleby HI BT 3+3: Three Surfboards in One?

When a two-time longboard world champion drops a new surfboard design, the surf world pays attention.

When that surfer is Harley Ingleby—the man behind the world famous MID6—it’s worth paying more than attention. It’s worth considering rearranging the quiver!

This year, Harley and renowned shaper Billy Tolhurst, in partnership with Thunderbolt Surfboards, have released what may be his most versatile performance board yet: the HI BT 3+3.

It’s not just a new outline. It’s not a small tweak. It’s a board that legitimately offers three different fin personalities in one shape, without gimmicks or weird asymmetrical outlines.

In Harley’s words:

“It was years of R&D, endless prototypes, and a lot of time in all kinds of surf. We wanted a board that truly sits between the MOE and the MID6 — more performance, more speed, more range, more fun.”

I’ve been lucky enough to be testing this board out pre-release (yes a full review is coming soon!) and caught up with Harley to chat about his latest design, the theory that went into it and a whole bunch of useful info that will help you decide if you should be grabbing one!

What is the HI BT 3+3?

At its core, the BT 3+3 is a high-performance fish-inspired surfboard, designed to be ridden in anything from playful beachies to fast, running points. It’s a board that fills a gap Harley identified in his line:

• More performance and release than the MOE
• More small-wave playfulness than the MID6
• Faster and looser than a standard mid-length
• More range and hold than a traditional fish or twin

In short, it’s a go-to travel board and a daily driver for a huge range of surfers.

The name comes from its defining feature: a 3+3 fin plug system that allows the board to be ridden as:

① A True Quad

For speed, drive, and control.

② A True Twin

For looseness, skatey bursts of speed, and flow.

③ An Asymmetric Hybrid

Twin on the toe side, quad on the heel side for a mixed-rail feel.

Harley says:

“Most of what I loved about asymmetrical boards was actually the fin setup—not the strange outlines. With the HI BT 3+3 you get all that versatility without having to reshape or commit to a weird design.”

This is a genuinely R&D-driven evolution of Harley’s earlier experiments with twin asym setups released in 2016.

 

 

The R&D: What Went Into the Design

Harley didn’t mince words on this:

“It’s the most R&D we’ve ever done on a board.”

The team tested dozens of combinations of:

• Rocker profiles
• Bottom contours
• Flyer/tail geometry
• Rail volumes
• Fin placements

They wanted a board that could be surfed:

• Short and snappy in tight pockets
• Mid-length style on longer open faces
• With confidence in hollow, punchy surf

The tail uses a sting-style flyer into a deep fish tail, providing:

• Release in turns even on higher-volume sizes
• Rail engagement at speed
• Predictable hold with quad fins engaged
• Smooth transitions between longer and shorter arcs

The overall result is a board that sits at the interesting intersection of:

• Performance shortboard characteristics
  Fish-style speed and looseness
  Mid-length paddle and glide

 

 

 

Rocker, Foil & Performance Breakdown

The BT3+3 is built for speed that requires very little effort. Harley breaks it down like this:

Nose Rocker

Still performance-oriented — forgiving on late drops, steeper ledges, and critical takeoffs.

Mid Rocker

• Slightly flatter than the MID6 or MOE, resulting in instant acceleration.

Tail + Flyer Design

A sting-style flyer makes the tail break line in a way that keeps larger volumes nimble, especially off the lip.

Rails

• Low and sensitive
• Designed to bite quickly on rail
• Creates confidence in faster or hollow surf

Harley tested the BT 3+3 in everything from beach breaks at home to long Indonesian reefs:

“It’s super fast, super zippy, super loose… I’ve surfed it in hollow, heavier days and it handles it way better than you’d expect.”

 

 

Fin Setup Recommendations

Harley shared his exact go-to setups. For surfers who want the same feel he rides, here are the guidelines:

The quad combo works because of one key detail:

“The Reactor is upright and pivoty, but with a big base for drive. The Performer rears have more rake, great control, and don’t feel tracky.”

Thunderbolt will be releasing a PG quad set specifically recommended for this model.

 

 

 

Size Range & Volume Guide

The BT3+3 has the deepest size run ever in Harley’s line starting at a 5’10 (32L) all the way to 7’2 (50L) with six sizing steps in between.

This range means it can be ridden by:

• First-board beginners
• Returning surfers
• Intermediate cruisers
• Advanced shortboarders
• Proper chargers needing a travel all-rounder

Harley’s sizing notes:

“If you’re between two sizes, go longer. These boards paddle incredibly well, so extra length is only going to help you.”

Sizing Comparing to the MID6

Example:

• 6’4 MID6 ≈ 36L
• 6’2 BT3+3 ≈ 36L but paddles slightly better due to width + flatter entry rocker.

 

 

 

Who Is the BT3+3 For?

Harley sees it working for:

He says:

“A pro surfer will froth on this board for travel or day-to-day surf — and a beginner could legitimately use a 7’0 or 7’2 as their first surfboard.”

 

 

Ideal Wave Conditions

Harley has put the board through a wide wave spectrum. The recommended sweet spot: is waist high to head high (1–6 ft) but it’s fully capable in a huge range of conditions from knee high playful runners to overhead, fast, bowly waves

Ideal surf includes:

• Punchy beach breaks
• Running point breaks
• Reef waves with pockets

The fish tail, when surfed as a quad, behaves like:

“Two pin tails that bite when you’re flying. It gives you control when you need it.”

 

 

Why You Should Add It To Your Quiver

There are plenty of small-wave performance boards on the market, and plenty of modern mid-lengths. But very few boards truly bridge the space between those worlds.

The BT3+3 is:

✔ A one-board travel solution
✔ A daily driver for most conditions
✔ A progression vehicle for intermediates
✔ A play machine for advanced surfers
✔ A gateway board for people curious about asym fins without committing to a strange shape

The simplest summary?

If you surf a lot of good but not perfect waves, this board is designed for your real-world surfing.

Final Thoughts

It’s a concept-driven evolution of years of experimentation, now delivered in a way almost any surfer can benefit from.

Harley’s closing words say it best:

“It’s the most fun I’ve had on a board in a long time… and I’m riding every size in the range.”

Will you be adding the HI BT 3+3 to your quiver?